diff --git a/docs/coordinate_conversions_hard_compound.rst b/docs/coordinate_conversions_hard_compound.rst
index 1c8260190..fa3b8df22 100644
--- a/docs/coordinate_conversions_hard_compound.rst
+++ b/docs/coordinate_conversions_hard_compound.rst
@@ -14,15 +14,16 @@ Geographic2D with Height Offsets
         Length $geoidUndulation
     ); // returns a new GeographicPoint
 
-Geographic3D to Geographic2D+GravityRelatedHeight (GTX)
--------------------------------------------------------
+Geographic3D to Geographic2D+GravityRelatedHeight From Grid (geographic)
+------------------------------------------------------------------------
+The following grid file types are supported: ``.gtx`` (``GTXGrid``), ``.mnt/.tac`` from IGN France (``IGNFHeightGrid``) and ``.txt`` from IGN Spain (``IGNESHeightGrid``)
 
 .. code-block:: php
 
     $point = CompoundPoint::create(...);
-    $newPoint = $point->geographic3DTo2DPlusGravityHeightGTX(
+    $newPoint = $point->geographic3DTo2DPlusGravityHeightFromGrid(
         Geographic3D $to,
-        GTXGrid $geoidHeightCorrectionModelFile
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ); // returns a new GeographicPoint
 
 Geographic3D to Geographic2D+GravityRelatedHeight (OSGM-GB)
@@ -33,6 +34,5 @@ Geographic3D to Geographic2D+GravityRelatedHeight (OSGM-GB)
     $point = CompoundPoint::create(...);
     $newPoint = $point->geographic3DTo2DPlusGravityHeightOSGM15(
         Geographic3D $to,
-        OSTNOSGM15Grid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        OSTNOSGM15Grid $geoidHeightCorrectionModelFile
     ); // returns a new GeographicPoint
diff --git a/docs/coordinate_conversions_hard_geographic.rst b/docs/coordinate_conversions_hard_geographic.rst
index ed6317100..36afa4499 100644
--- a/docs/coordinate_conversions_hard_geographic.rst
+++ b/docs/coordinate_conversions_hard_geographic.rst
@@ -189,20 +189,6 @@ Geocentric translation
         Length $zAxisTranslation
     ); // returns a new GeographicPoint
 
-Geocentric translation by grid interpolation (IGNF)
----------------------------------------------------
-
-.. code-block:: php
-
-    $point = GeographicPoint::create(...);
-    $newPoint = $point->geocentricTranslationByGridInterpolationIGNF(
-        Geographic $to,
-        IGNFGeocentricTranslationGrid $geocentricTranslationFile,
-        string $EPSGCodeForInterpolationCRS,
-        string $EPSGCodeForStandardCT,
-        bool $inReverse
-    ); // returns a new GeographicPoint
-
 Geographic <=> geocentric conversion
 ------------------------------------
 
@@ -238,15 +224,16 @@ Geographic2D with Height Offsets
         Length $geoidUndulation
     ); // returns a new CompoundPoint
 
-Geographic3D to Geographic2D+GravityRelatedHeight (GTX)
+Geographic3D to Geographic2D+GravityRelatedHeight From Grid
 -----------------------------------------------------------
+The following grid file types are supported: ``.gtx`` (``GTXGrid``), ``.mnt/.tac`` from IGN France (``IGNFHeightGrid``) and ``.txt`` from IGN Spain (``IGNESHeightGrid``)
 
 .. code-block:: php
 
     $point = GeographicPoint::create(...);
-    $newPoint = $point->geographic3DTo2DPlusGravityHeightGTX(
+    $newPoint = $point->geographic3DTo2DPlusGravityHeightFromGrid(
         Compound $to,
-        GTXGrid $geoidHeightCorrectionModelFile
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ); // returns a new CompoundPoint
 
 Geographic3D to Geographic2D+GravityRelatedHeight (OSGM-GB)
@@ -257,19 +244,19 @@ Geographic3D to Geographic2D+GravityRelatedHeight (OSGM-GB)
     $point = GeographicPoint::create(...);
     $newPoint = $point->geographic3DTo2DPlusGravityHeightOSGM15(
         Compound $to,
-        OSTNOSGM15Grid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        OSTNOSGM15Grid $geoidHeightCorrectionModelFile
     ); // returns a new CompoundPoint
 
-Geographic3D to GravityRelatedHeight (GTX)
+Geographic3D to GravityRelatedHeight From Grid
 ----------------------------------------------
+The following grid file types are supported: ``.gtx`` (``GTXGrid``), ``.mnt/.tac`` from IGN France (``IGNFHeightGrid``) and ``.txt`` from IGN Spain (``IGNESHeightGrid``)
 
 .. code-block:: php
 
     $point = GeographicPoint::create(...);
-    $newPoint = $point->geographic3DToGravityHeightGTX(
+    $newPoint = $point->geographic3DTo2DPlusGravityHeightFromGrid((
         Vertical $to,
-        GTXGrid $geoidHeightCorrectionModelFile
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ); // returns a new VerticalPoint
 
 Geographic3D to GravityRelatedHeight (OSGM-GB)
@@ -687,20 +674,6 @@ Molodensky-Badekas Position Vector transformation
         Length $ordinate3OfEvaluationPoint
     ); // returns a new GeographicPoint
 
-NADCON5
--------
-
-.. code-block:: php
-
-    $point = GeographicPoint::create(...);
-    $newPoint = $point->NADCON5(
-        Geographic $to,
-        NADCON5Grid $latitudeDifferenceFile,
-        NADCON5Grid $longitudeDifferenceFile,
-        ?NADCON5Grid $ellipsoidalHeightDifferenceFile,
-        bool $inReverse
-    ); // returns a new GeographicPoint
-
 New Zealand Map Grid
 --------------------
 
@@ -715,18 +688,6 @@ New Zealand Map Grid
         Length $falseNorthing
     ); // returns a new ProjectedPoint
 
-NTv2
-----
-
-.. code-block:: php
-
-    $point = GeographicPoint::create(...);
-    $newPoint = $point->NTv2(
-        Geographic $to,
-        NTv2Grid $latitudeAndLongitudeDifferenceFile,
-        bool $inReverse
-    ); // returns a new GeographicPoint
-
 Oblique Stereographic
 ---------------------
 
@@ -742,6 +703,19 @@ Oblique Stereographic
         Length $falseNorthing
     ); // returns a new ProjectedPoint
 
+Offsets From Grid
+-----------------
+The following grid file types are supported: ``.gsb`` (``NTv2Grid``), ``.txt/.mnt/.tac`` from IGN France (``IGNFGeocentricTranslationGrid``) and ``.b`` from NOAA (``NADCON5Grids``)
+
+.. code-block:: php
+
+    $point = GeographicPoint::create(...);
+    $newPoint = $point->offsetsFromGrid(
+        Geographic $to,
+        GeographicGrid $offsetsFile,
+        bool $inReverse
+    ); // returns a new GeographicPoint
+
 OSTN15 (Ordnance Survey National Transformation)
 ------------------------------------------------
 
diff --git a/docs/coordinate_conversions_hard_vertical.rst b/docs/coordinate_conversions_hard_vertical.rst
index 0fd0bba23..8641ba457 100644
--- a/docs/coordinate_conversions_hard_vertical.rst
+++ b/docs/coordinate_conversions_hard_vertical.rst
@@ -11,24 +11,24 @@ Height <=> Depth reversal
         Vertical $to
     ); // returns a new VerticalPoint
 
-Vertical Offset
----------------
+Offset
+------
 
 .. code-block:: php
 
     $point = VerticalPoint::create(...);
-    $newPoint = $point->verticalOffset(
+    $newPoint = $point->offset(
         Vertical $to,
         Length $verticalOffset
     ); // returns a new VerticalPoint
 
-Vertical Offset and Slope
--------------------------
+Offset and Slope
+----------------
 
 .. code-block:: php
 
     $point = VerticalPoint::create(...);
-    $newPoint = $point->verticalOffsetAndSlope(
+    $newPoint = $point->offsetAndSlope(
         Vertical $to,
         Angle $ordinate1OfEvaluationPoint,
         Angle $ordinate2OfEvaluationPoint,
@@ -38,15 +38,17 @@ Vertical Offset and Slope
         GeographicPoint $horizontalPoint
     ); // returns a new VerticalPoint
 
-Vertical Offset by Grid Interpolation (GTX)
--------------------------------------------
+Offset From Grid File
+---------------------
+
+The following grid file types are supported: ``.gtx`` (``GTXGrid``), ``.mnt/.tac`` from IGN France (``IGNFHeightGrid``) and ``.txt`` from IGN Spain (``IGNESHeightGrid``)
 
 .. code-block:: php
 
     $point = VerticalPoint::create(...);
-    $newPoint = $point->verticalOffsetGTX(
+    $newPoint = $point->offsetFromGrid(
         Vertical $to,
-        GTXGrid $verticalOffsetFile,
+        GeographicGeoidHeightGrid $offsetsFile,
         bool $inReverse,
         GeographicPoint $horizontalPoint
     ); // returns a new VerticalPoint
diff --git a/src/CompoundPoint.php b/src/CompoundPoint.php
index 05e836e02..c6644af66 100644
--- a/src/CompoundPoint.php
+++ b/src/CompoundPoint.php
@@ -13,9 +13,7 @@
 use DateTimeInterface;
 use PHPCoord\CoordinateOperation\AutoConversion;
 use PHPCoord\CoordinateOperation\ConvertiblePoint;
-use PHPCoord\CoordinateOperation\GTXGrid;
-use PHPCoord\CoordinateOperation\IGNESHeightGrid;
-use PHPCoord\CoordinateOperation\IGNFHeightGrid;
+use PHPCoord\CoordinateOperation\GeographicGeoidHeightGrid;
 use PHPCoord\CoordinateOperation\OSTNOSGM15Grid;
 use PHPCoord\CoordinateReferenceSystem\Compound;
 use PHPCoord\CoordinateReferenceSystem\CoordinateReferenceSystem;
@@ -190,8 +188,7 @@ public function geographic2DWithHeightOffsets(
      */
     public function geographic3DTo2DPlusGravityHeightOSGM15(
         Geographic3D $to,
-        OSTNOSGM15Grid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        OSTNOSGM15Grid $geoidHeightCorrectionModelFile
     ): GeographicPoint {
         $osgb36NationalGrid = Projected::fromSRID(Projected::EPSG_OSGB36_BRITISH_NATIONAL_GRID);
         $etrs89NationalGrid = new Projected(
@@ -206,58 +203,23 @@ public function geographic3DTo2DPlusGravityHeightOSGM15(
         return GeographicPoint::create(
             $this->horizontalPoint->getLatitude(),
             $this->horizontalPoint->getLongitude(),
-            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getVerticalAdjustment($projected)),
+            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getHeightAdjustment($projected)),
             $to,
             $this->getCoordinateEpoch()
         );
     }
 
     /**
-     * Geog3D to Geog2D+GravityRelatedHeight (gtx).
+     * Geog3D to Geog2D+GravityRelatedHeight.
      */
-    public function geographic3DTo2DPlusGravityHeightGTX(
+    public function geographic3DTo2DPlusGravityHeightFromGrid(
         Geographic3D $to,
-        GTXGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ): GeographicPoint {
         return GeographicPoint::create(
             $this->horizontalPoint->getLatitude(),
             $this->horizontalPoint->getLongitude(),
-            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getAdjustment($this->horizontalPoint)),
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geog3D to Geog2D+GravityRelatedHeight (IGNES).
-     */
-    public function geographic3DTo2DPlusGravityHeightIGNES(
-        Geographic3D $to,
-        IGNESHeightGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
-    ): GeographicPoint {
-        return GeographicPoint::create(
-            $this->horizontalPoint->getLatitude(),
-            $this->horizontalPoint->getLongitude(),
-            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getAdjustment($this->horizontalPoint)),
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geog3D to Geog2D+GravityRelatedHeight (IGNF).
-     */
-    public function geographic3DTo2DPlusGravityHeightIGNF(
-        Geographic3D $to,
-        IGNFHeightGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
-    ): GeographicPoint {
-        return GeographicPoint::create(
-            $this->horizontalPoint->getLatitude(),
-            $this->horizontalPoint->getLongitude(),
-            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getAdjustment($this->horizontalPoint)),
+            $this->verticalPoint->getHeight()->add($geoidHeightCorrectionModelFile->getHeightAdjustment($this->horizontalPoint)),
             $to,
             $this->getCoordinateEpoch()
         );
diff --git a/src/CoordinateOperation/BilinearInterpolation.php b/src/CoordinateOperation/BilinearInterpolation.php
index 4019fc772..dcbff3396 100644
--- a/src/CoordinateOperation/BilinearInterpolation.php
+++ b/src/CoordinateOperation/BilinearInterpolation.php
@@ -23,14 +23,14 @@ trait BilinearInterpolation
     protected float $columnGridInterval;
     protected float $rowGridInterval;
 
-    public function interpolateBilinear(
+    public function interpolate(
         float $x,
         float $y
     ): array {
-        $corners = $this->getCornersForBilinear($x, $y);
+        $corners = $this->getCorners($x, $y);
 
-        $dx = $corners['lowerRight']->getX() === $corners['lowerLeft']->getX() ? 0 : (($x - $corners['lowerLeft']->getX()) / ($corners['lowerRight']->getX() - $corners['lowerLeft']->getX()));
-        $dy = $corners['upperLeft']->getY() === $corners['lowerLeft']->getY() ? 0 : (($y - $corners['lowerLeft']->getY()) / ($corners['upperLeft']->getY() - $corners['lowerLeft']->getY()));
+        $dx = $corners['lowerRight']->getX() === $corners['lowerLeft']->getX() ? 0 : (($x - $corners['lowerLeft']->getX()) / $this->columnGridInterval);
+        $dy = $corners['upperLeft']->getY() === $corners['lowerLeft']->getY() ? 0 : (($y - $corners['lowerLeft']->getY()) / $this->rowGridInterval);
 
         $interpolations = [];
         for ($i = 0, $count = count($corners['lowerLeft']->getValues()); $i < $count; ++$i) {
@@ -59,7 +59,7 @@ private function interpolateLinear(float $p, float $valueAt0, float $valueAt1):
     /**
      * @return GridValues[]
      */
-    private function getCornersForBilinear(float $x, float $y): array
+    private function getCorners(float $x, float $y): array
     {
         $xIndex = (int) (($x - $this->startX) / $this->columnGridInterval);
         $yIndex = (int) (($y - $this->startY) / $this->rowGridInterval);
diff --git a/src/CoordinateOperation/BiquadraticInterpolation.php b/src/CoordinateOperation/BiquadraticInterpolation.php
index 7da1526cd..5766fe41f 100644
--- a/src/CoordinateOperation/BiquadraticInterpolation.php
+++ b/src/CoordinateOperation/BiquadraticInterpolation.php
@@ -9,6 +9,9 @@
 namespace PHPCoord\CoordinateOperation;
 
 use function assert;
+use function count;
+use function max;
+use function min;
 
 trait BiquadraticInterpolation
 {
@@ -21,6 +24,32 @@ trait BiquadraticInterpolation
     protected float $columnGridInterval;
     protected float $rowGridInterval;
 
+    public function interpolate(
+        float $x,
+        float $y
+    ): array {
+        $corners = $this->getCorners($x, $y);
+
+        $dx = $corners['lowerRight']->getX() === $corners['lowerLeft']->getX() ? 0 : (($x - $corners['lowerLeft']->getX()) / $this->columnGridInterval);
+        $dy = $corners['upperLeft']->getY() === $corners['lowerLeft']->getY() ? 0 : (($y - $corners['lowerLeft']->getY()) / $this->rowGridInterval);
+
+        $interpolations = [];
+        for ($i = 0, $count = count($corners['lowerLeft']->getValues()); $i < $count; ++$i) {
+            //Interpolate value at lower row
+            $y0 = $this->interpolateQuadratic($dx, $corners['lowerLeft']->getValues()[$i], $corners['lowerCentre']->getValues()[$i], $corners['lowerRight']->getValues()[$i]);
+            //Interpolate value at middle row
+            $y1 = $this->interpolateQuadratic($dx, $corners['middleLeft']->getValues()[$i], $corners['middleCentre']->getValues()[$i], $corners['middleRight']->getValues()[$i]);
+            //Interpolate value at upper row
+            $y2 = $this->interpolateQuadratic($dx, $corners['upperLeft']->getValues()[$i], $corners['upperCentre']->getValues()[$i], $corners['upperRight']->getValues()[$i]);
+
+            //Interpolate between rows
+            $xy = $this->interpolateQuadratic($dy, $y0, $y1, $y2);
+            $interpolations[] = $xy;
+        }
+
+        return $interpolations;
+    }
+
     /**
      * Quadratic interpolation at point p, where p is between 0 and 2.
      * Converted from NOAA FORTRAN implementation, this function apparently uses Newton-Gregory forward polynomial.
@@ -35,4 +64,39 @@ private function interpolateQuadratic(float $p, float $valueAt0, float $valueAt1
 
         return $valueAt0 + $p * $difference1 + $p / 2 * ($p - 1) * $differenceDifferences;
     }
+
+    /**
+     * @return GridValues[]
+     */
+    private function getCorners(float $x, float $y): array
+    {
+        // Method:
+        // Fit a 3x3 window over the random point. The closest
+        // 2x2 points will surround the point. But based on which
+        // quadrant of that 2x2 cell in which the point falls, the
+        // 3x3 window could extend NW, NE, SW or SE from the 2x2 cell.
+
+        // Find which column should be LEAST when fitting
+        // a 3x3 window around $longitude.
+        $xIndex = (int) (($x - $this->startX) / $this->columnGridInterval - 0.5);
+
+        // Find which row should be LEAST when fitting
+        // a 3x3 window around $latitude.
+        $yIndex = (int) (($y - $this->startY) / $this->rowGridInterval - 0.5);
+
+        $xIndex = min(max($xIndex, 0), $this->numberOfColumns - 3);
+        $yIndex = min(max($yIndex, 0), $this->numberOfRows - 3);
+
+        return [
+            'lowerLeft' => $this->getRecord($xIndex, $yIndex),
+            'lowerCentre' => $this->getRecord($xIndex + 1, $yIndex),
+            'lowerRight' => $this->getRecord($xIndex + 2, $yIndex),
+            'middleLeft' => $this->getRecord($xIndex, $yIndex + 1),
+            'middleCentre' => $this->getRecord($xIndex + 1, $yIndex + 1),
+            'middleRight' => $this->getRecord($xIndex + 2, $yIndex + 1),
+            'upperLeft' => $this->getRecord($xIndex, $yIndex + 2),
+            'upperCentre' => $this->getRecord($xIndex + 1, $yIndex + 2),
+            'upperRight' => $this->getRecord($xIndex + 2, $yIndex + 2),
+        ];
+    }
 }
diff --git a/src/CoordinateOperation/CoordinateOperationMethods.php b/src/CoordinateOperation/CoordinateOperationMethods.php
index e9f7a06c6..2a9086ceb 100644
--- a/src/CoordinateOperation/CoordinateOperationMethods.php
+++ b/src/CoordinateOperation/CoordinateOperationMethods.php
@@ -844,8 +844,8 @@ class CoordinateOperationMethods
         self::EPSG_TRANSVERSE_MERCATOR => 'transverseMercator',
         self::EPSG_TRANSVERSE_MERCATOR_SOUTH_ORIENTATED => 'transverseMercator',
         self::EPSG_TRANSVERSE_MERCATOR_ZONED_GRID_SYSTEM => 'transverseMercatorZonedGrid',
-        self::EPSG_VERTICAL_OFFSET => 'verticalOffset',
-        self::EPSG_VERTICAL_OFFSET_AND_SLOPE => 'verticalOffsetAndSlope',
+        self::EPSG_VERTICAL_OFFSET => 'offset',
+        self::EPSG_VERTICAL_OFFSET_AND_SLOPE => 'offsetAndSlope',
         self::EPSG_GENERAL_POLYNOMIAL_OF_DEGREE_2 => 'generalPolynomial',
         self::EPSG_GENERAL_POLYNOMIAL_OF_DEGREE_6 => 'generalPolynomial',
         self::EPSG_REVERSIBLE_POLYNOMIAL_OF_DEGREE_4 => 'reversiblePolynomial',
@@ -862,18 +862,18 @@ class CoordinateOperationMethods
         self::EPSG_ORDNANCE_SURVEY_NATIONAL_TRANSFORMATION => 'OSTN15',
         self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_OSGM_GB => 'geographic3DTo2DPlusGravityHeightOSGM15',
         self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_OSGM_GB => 'geographic3DToGravityHeightOSGM15',
-        self::EPSG_NADCON5_2D => 'NADCON5',
-        self::EPSG_NADCON5_3D => 'NADCON5',
-        self::EPSG_NTV2 => 'NTv2',
+        self::EPSG_NADCON5_2D => 'offsetsFromGridNADCON5',
+        self::EPSG_NADCON5_3D => 'offsetsFromGridNADCON5',
+        self::EPSG_NTV2 => 'offsetsFromGrid',
         self::EPSG_ZERO_TIDE_HEIGHT_TO_MEAN_TIDE_HEIGHT_EVRF2019 => 'zeroTideHeightToMeanTideHeightEVRF2019',
-        self::EPSG_GEOCENTRIC_TRANSLATION_BY_GRID_INTERPOLATION_IGN => 'geocentricTranslationByGridInterpolationIGNF',
-        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_GTX => 'geographic3DTo2DPlusGravityHeightGTX',
-        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_GTX => 'geographic3DToGravityHeightGTX',
-        self::EPSG_VERTICAL_OFFSET_BY_GRID_INTERPOLATION_GTX => 'verticalOffsetGTX',
-        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_IGN2009 => 'geographic3DTo2DPlusGravityHeightIGNF',
-        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_IGN2009 => 'geographic3DToGravityHeightIGNF',
-        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_EGM2008 => 'geographic3DTo2DPlusGravityHeightIGNES',
-        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_EGM2008 => 'geographic3DToGravityHeightIGNES',
+        self::EPSG_GEOCENTRIC_TRANSLATION_BY_GRID_INTERPOLATION_IGN => 'offsetsFromGrid',
+        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_GTX => 'geographic3DTo2DPlusGravityHeightFromGrid',
+        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_GTX => 'geographic3DToGravityHeightFromGrid',
+        self::EPSG_VERTICAL_OFFSET_BY_GRID_INTERPOLATION_GTX => 'offsetFromGrid',
+        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_IGN2009 => 'geographic3DTo2DPlusGravityHeightFromGrid',
+        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_IGN2009 => 'geographic3DToGravityHeightFromGrid',
+        self::EPSG_GEOG3D_TO_GEOG2D_PLUS_GRAVITYRELATEDHEIGHT_EGM2008 => 'geographic3DTo2DPlusGravityHeightFromGrid',
+        self::EPSG_GEOGRAPHIC3D_TO_GRAVITYRELATEDHEIGHT_EGM2008 => 'geographic3DToGravityHeightFromGrid',
     ];
 
     public static function getFunctionName(string $srid): string
diff --git a/src/CoordinateOperation/CoordinateOperationParams.php b/src/CoordinateOperation/CoordinateOperationParams.php
index 53d4ec2bb..ebf8bf81b 100644
--- a/src/CoordinateOperation/CoordinateOperationParams.php
+++ b/src/CoordinateOperation/CoordinateOperationParams.php
@@ -5405,7 +5405,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1313' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CanadaProvider',
             ],
@@ -6304,7 +6304,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1463' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27MAY76NAD831986OntarioProvider',
             ],
@@ -7118,7 +7118,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1568' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NZGD1949NZGD2000NewZealandProvider',
             ],
@@ -7158,13 +7158,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1573' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD831986QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1575' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27CGQ77NAD831986QuebecProvider',
             ],
@@ -9246,7 +9246,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1670' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NZGD1949NZGD2000NewZealandProvider',
             ],
@@ -9690,49 +9690,49 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1688' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS77NAD83CSRS1997NewBrunswickProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1689' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS777NAD83CSRS1997PrinceEdwardProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1690' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27MAY76NAD831986OntarioProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1691' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27CGQ77NAD831986QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1692' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1693' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CanadaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1696' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1697' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997SaskatchewanProvider',
             ],
@@ -9775,13 +9775,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1702' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS2002AlbertaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1703' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997SaskatchewanProvider',
             ],
@@ -10645,13 +10645,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1803' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2AGD66GDA94AustraliaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::1804' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2AGD84GDA94AustraliaProvider',
             ],
@@ -24087,49 +24087,49 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5525' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2CA61SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5526' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2CA7072SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5528' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2SAD69SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5529' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2SAD6996SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5540' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2CA61SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5541' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2CA7072SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5542' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2SAD69SIRGAS2000BrazilProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5543' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2SAD6996SIRGAS2000BrazilProvider',
             ],
@@ -24669,7 +24669,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5661' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ED50ETRS89CataloniaProvider',
             ],
@@ -24962,7 +24962,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::5891' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2MGIETRS89AustriaProvider',
             ],
@@ -28360,13 +28360,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6188' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2LisbonETRS89PortugalProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6189' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv273ETRS89PortugalProvider',
             ],
@@ -32401,13 +32401,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6712' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2TokyoJGD2000JapanProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6713' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2JGD2000JGD2011JapanProvider',
             ],
@@ -32602,7 +32602,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6740' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2TokyoJGD2000JapanProvider',
             ],
@@ -34986,7 +34986,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::6948' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2RD83ETRS89SaxonyProvider',
             ],
@@ -43554,13 +43554,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7673' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2LV03ETRS89SwitzerlandProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7674' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2LV03ETRS89SwitzerlandProvider',
             ],
@@ -45176,7 +45176,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7788' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2LV03ETRS89SwitzerlandProvider',
             ],
@@ -47835,19 +47835,19 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7969' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNGVD29NAVD88CONUSWestProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7970' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNGVD29NAVD88CONUSCentralProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::7971' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNGVD29NAVD88CONUSEastProvider',
             ],
@@ -51340,22 +51340,12 @@ class CoordinateOperationParams
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXETRS89Baltic1957SlovakiaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8362' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXETRS89EVRF2007SlovakiaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8365' => [
             'xAxisTranslation' => [
@@ -51546,7 +51536,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8369' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2BD79ETRS89BelgiumProvider',
             ],
@@ -52004,19 +51994,19 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8444' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2GDA94GDA2020ChristmasIslandProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8445' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2GDA94GDA2020CocosIslandsProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::8447' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2GDA94GDA2020AustraliaProvider',
             ],
@@ -57930,73 +57920,73 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9105' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS77NAD831986NovaScotiaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9106' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS77NAD83CSRS2010NovaScotiaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9107' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997OntarioProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9108' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997OTorontoProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9109' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27MAY76NAD83CSRS1997OntarioProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9110' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997OntarioProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9111' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD831986SaskatchewanProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9113' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997BritishColumbiaCRDProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9115' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS2002BritishColumbiaCRDProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9117' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997BritishColumbiaCRDProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9118' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997BritishColumbiaVancouverIslandProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9119' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS2002BritishColumbiaCRDProvider',
             ],
@@ -59303,13 +59293,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9232' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ISN93ISN2016IcelandProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9233' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ISN2004ISN2016IcelandProvider',
             ],
@@ -59352,55 +59342,55 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9236' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS777NAD83CSRS1997PrinceEdwardProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9237' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ATS77NAD83CSRS1997NewBrunswickProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9238' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997NewBrunswickProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9239' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9240' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27CGQ77NAD83CSRS1997QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9241' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997QuebecProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9242' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD27NAD83CSRS1997SaskatchewanProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9243' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS1997SaskatchewanProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9244' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS2002AlbertaProvider',
             ],
@@ -59660,7 +59650,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9282' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2RDETRS89NetherlandsProvider',
             ],
@@ -59753,153 +59743,88 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9310' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2DHDNETRS89SaarlandProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9312' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXAuckland1946NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9313' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXBluff1955NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9314' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXDunedin1958NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9315' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXDunedinBluff1960NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9316' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGisborne1926NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9317' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXLyttelton1937NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9318' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXMoturiki1953NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9319' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNapier1962NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9320' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNelson1955NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9321' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXOneTreePoint1964NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9322' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXStewartIsland1977NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9323' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXTaranaki1970NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9324' => [
-            'verticalOffsetFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXWellington1953NZVD2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9325' => [
             'geoidHeightCorrectionModelFile' => [
@@ -59914,68 +59839,28 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9327' => [
-            'geocentricTranslationFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFGeocentricTranslationNTFRGF93Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4171',
-                'uom' => null,
-                'reverses' => false,
-            ],
-            'EPSGCodeForStandardCT' => [
-                'value' => 'urn:ogc:def:coordinateOperation:EPSG::1651',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9328' => [
-            'geocentricTranslationFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFGeocentricTranslationNEA74NoumeaRGNC9193Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4749',
-                'uom' => null,
-                'reverses' => false,
-            ],
-            'EPSGCodeForStandardCT' => [
-                'value' => 'urn:ogc:def:coordinateOperation:EPSG::15886',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9329' => [
-            'geocentricTranslationFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFGeocentricTranslationIGN72GrandeTerreRGNC9193Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4749',
-                'uom' => null,
-                'reverses' => false,
-            ],
-            'EPSGCodeForStandardCT' => [
-                'value' => 'urn:ogc:def:coordinateOperation:EPSG::15882',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9330' => [
-            'geocentricTranslationFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFGeocentricTranslationIGN72GrandeTerreRGNC9193NoumeaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4749',
-                'uom' => null,
-                'reverses' => false,
-            ],
-            'EPSGCodeForStandardCT' => [
-                'value' => 'urn:ogc:def:coordinateOperation:EPSG::15882',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9334' => [
             'xAxisTranslation' => [
@@ -60577,13 +60462,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9408' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ED50ETRS89SpainProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9409' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2ED50ETRS89BalearicIslandsProvider',
             ],
@@ -60806,22 +60691,12 @@ class CoordinateOperationParams
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGDA2020AHDProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::7844',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9467' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGDA94AHDProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4283',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9472' => [
             'xAxisTranslation' => [
@@ -61006,7 +60881,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9550' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS2010NewfoundlandProvider',
             ],
@@ -61037,451 +60912,246 @@ class CoordinateOperationParams
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9585' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9586' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9587' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9588' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9589' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9590' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\OSTN15OSGM15Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9593' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXETRS89NN2000Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9594' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXETRS89NN1954Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9595' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID18CONUSProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6318',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9596' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID12BAlaskaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6318',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9597' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXETRS89NAPProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9605' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPSpainProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9606' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPSpainProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9607' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPSpainProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9608' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPSpainProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9609' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPSpainProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4258',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9610' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9611' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9612' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9613' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9614' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9615' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9616' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNESHeightETRS89REDNAPCanaryIslandsProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4081',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9622' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID18PRVIProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6318',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9623' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID18PRVIProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6318',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9624' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID12BGuamMIProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6325',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9625' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID12BGuamMIProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6325',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9626' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGEOID12BAmericaSamoaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::6322',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9627' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNZGeoid2009Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9628' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXNZGeoid2016Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4167',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9631' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09Guadeloupe1988Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9632' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09IGN1988LesSaintesProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9633' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09IGN1988MarieGalanteProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9634' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09IGN1988SaintBarthelemyProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9635' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09IGN1988SaintMartinProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9636' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09IGN2008LaDesiradeProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9637' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGAF09Martinique1987Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::5489',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9640' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGNC9193NGNC08NewCaledoniaProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4749',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9641' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGSPM06Danger1950Provider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4463',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9642' => [
             'geoidHeightCorrectionModelFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightWGS84IGN2008LaDesiradeProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::4558',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9673' => [
             'latitudeOfFalseOrigin' => [
@@ -61865,7 +61535,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9689' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2GDA94GDA2020AustraliaProvider',
             ],
@@ -61908,7 +61578,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9691' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2GDA94GDA2020AustraliaProvider',
             ],
@@ -61924,11 +61594,6 @@ class CoordinateOperationParams
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\GTXGDA2020AVWSProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::7844',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9703' => [
             'xAxisTranslation' => [
@@ -62545,7 +62210,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::9795' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2NAD831986NAD83CSRS2010AlbertaProvider',
             ],
@@ -62615,11 +62280,6 @@ class CoordinateOperationParams
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\IGNFHeightRGF93v2bNGFIGN69FranceProvider',
             ],
-            'EPSGCodeForInterpolationCRS' => [
-                'value' => 'urn:ogc:def:crs:EPSG::9782',
-                'uom' => null,
-                'reverses' => false,
-            ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::10085' => [
             'xAxisTranslation' => [
@@ -74224,7 +73884,7 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15486' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2LV03LV95SwitzerlandProvider',
             ],
@@ -77923,13 +77583,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15785' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2AGD84GDA94AustraliaProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15786' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2AGD66GDA94AustraliaProvider',
             ],
@@ -80793,13 +80453,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15948' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2DHDNETRS89GermanyProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15949' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2DHDNETRS89GermanyProvider',
             ],
@@ -81023,13 +80683,13 @@ class CoordinateOperationParams
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15954' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2DHDNETRS89GermanyProvider',
             ],
         ],
         'urn:ogc:def:coordinateOperation:EPSG::15955' => [
-            'latitudeAndLongitudeDifferenceFile' => [
+            'offsetsFile' => [
                 'reverses' => true,
                 'fileProvider' => 'PHPCoord\\CoordinateOperation\\NTv2DHDNETRS89GermanyProvider',
             ],
diff --git a/src/CoordinateOperation/GTXGrid.php b/src/CoordinateOperation/GTXGrid.php
index e9ecba047..a0b346692 100644
--- a/src/CoordinateOperation/GTXGrid.php
+++ b/src/CoordinateOperation/GTXGrid.php
@@ -8,7 +8,7 @@
 
 namespace PHPCoord\CoordinateOperation;
 
-use PHPCoord\GeographicPoint;
+use function in_array;
 use PHPCoord\UnitOfMeasure\Length\Metre;
 use SplFileObject;
 use function substr;
@@ -17,16 +17,17 @@
 /**
  * @see https://vdatum.noaa.gov/docs/gtx_info.html for documentation
  */
-class GTXGrid extends SplFileObject
+class GTXGrid extends GeographicGeoidHeightGrid
 {
     use BilinearInterpolation;
 
     private int $headerLength;
-    private string $offsetDataType;
+    private string $shiftDataType;
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
+        $this->storageOrder = self::STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE;
 
         $header = $this->getHeader();
         $this->startX = $header['xlonsw'];
@@ -41,50 +42,57 @@ public function __construct($filename)
         }
     }
 
-    public function getAdjustment(GeographicPoint $point): Metre
+    /**
+     * @return Metre[]
+     */
+    public function getValues($x, $y): array
     {
-        $latitude = $point->getLatitude()->getValue();
-        $longitude = $point->getLongitude()->getValue();
-        $offset = $this->interpolateBilinear($longitude, $latitude)[0];
+        $shift = $this->interpolate($x, $y)[0];
 
         // These are in millimeters for some reason... :/
-        if (in_array($this->getBasename(), ['vertconc.gtx', 'vertcone.gtx', 'vertconw.gtx'], true)) {
-            $offset /= 1000;
+        if (in_array($this->gridFile->getBasename(), ['vertconc.gtx', 'vertcone.gtx', 'vertconw.gtx'], true)) {
+            $shift /= 1000;
         }
 
-        return new Metre($offset);
+        return [new Metre($shift)];
     }
 
     private function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues
     {
-        $offset = $this->headerLength + ($latitudeIndex * $this->numberOfColumns + $longitudeIndex) * 4;
-        $this->fseek($offset);
-        $rawRow = $this->fread(4);
-        $data = unpack("{$this->offsetDataType}offset", $rawRow);
+        $recordId = match ($this->storageOrder) {
+            self::STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE => $longitudeIndex * $this->numberOfRows + $latitudeIndex,
+            self::STORAGE_ORDER_INCREASING_LONGITUDE_DECREASING_LATIITUDE => ($this->numberOfRows - $latitudeIndex - 1) * $this->numberOfColumns + $longitudeIndex,
+            self::STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE => $latitudeIndex * $this->numberOfColumns + $longitudeIndex,
+        };
+
+        $offset = $this->headerLength + $recordId * 4;
+        $this->gridFile->fseek($offset);
+        $rawRow = $this->gridFile->fread(4);
+        $data = unpack("{$this->shiftDataType}shift", $rawRow);
 
         return new GridValues(
             $longitudeIndex * $this->columnGridInterval + $this->startX,
             $latitudeIndex * $this->rowGridInterval + $this->startY,
-            [$data['offset']]
+            [$data['shift']]
         );
     }
 
     private function getHeader(): array
     {
-        $this->fseek(0);
-        $rawHeader = $this->fread(44);
+        $this->gridFile->fseek(0);
+        $rawHeader = $this->gridFile->fread(44);
         $ikind = substr($rawHeader, 40, 4);
         if (unpack('Nikind', $ikind)['ikind'] === 1) { // big endian
             $this->headerLength = 44;
-            $this->offsetDataType = 'G';
+            $this->shiftDataType = 'G';
             $data = unpack('Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon', $rawHeader);
         } elseif (unpack('Vikind', $ikind)['ikind'] === 1) { // little endian
             $this->headerLength = 44;
-            $this->offsetDataType = 'g';
+            $this->shiftDataType = 'g';
             $data = unpack('exlatsw/exlonsw/edlat/edlon/Vnlat/Vnlon', $rawHeader);
         } else { // not all files (e.g. NZ) have this endian check column, assume big endian
             $this->headerLength = 40;
-            $this->offsetDataType = 'G';
+            $this->shiftDataType = 'G';
             $data = unpack('Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon', $rawHeader);
         }
 
diff --git a/src/CoordinateOperation/GeographicGeoidHeightGrid.php b/src/CoordinateOperation/GeographicGeoidHeightGrid.php
new file mode 100644
index 000000000..b9781508a
--- /dev/null
+++ b/src/CoordinateOperation/GeographicGeoidHeightGrid.php
@@ -0,0 +1,26 @@
+<?php
+/**
+ * PHPCoord.
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace PHPCoord\CoordinateOperation;
+
+use PHPCoord\GeographicPoint;
+use PHPCoord\UnitOfMeasure\Length\Length;
+use PHPCoord\UnitOfMeasure\Length\Metre;
+
+abstract class GeographicGeoidHeightGrid extends Grid
+{
+    /**
+     * @return Metre[]
+     */
+    abstract public function getValues(float $x, float $y): array;
+
+    public function getHeightAdjustment(GeographicPoint $location): Length
+    {
+        return $this->getValues($location->getLongitude()->asDegrees()->getValue(), $location->getLatitude()->asDegrees()->getValue())[0];
+    }
+}
diff --git a/src/CoordinateOperation/GeographicGrid.php b/src/CoordinateOperation/GeographicGrid.php
new file mode 100644
index 000000000..ae8458f75
--- /dev/null
+++ b/src/CoordinateOperation/GeographicGrid.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * PHPCoord.
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace PHPCoord\CoordinateOperation;
+
+use function abs;
+use PHPCoord\CoordinateReferenceSystem\Geographic;
+use PHPCoord\GeographicPoint;
+use PHPCoord\UnitOfMeasure\Angle\ArcSecond;
+
+abstract class GeographicGrid extends Grid
+{
+    protected const ITERATION_CONVERGENCE = 0.0001;
+
+    public function applyForwardAdjustment(GeographicPoint $point, Geographic $to): GeographicPoint
+    {
+        $shifts = $this->getValues($point->getLongitude()->getValue(), $point->getLatitude()->getValue());
+
+        $latitude = $point->getLatitude()->add($shifts[0]);
+        $longitude = $point->getLongitude()->add($shifts[1]);
+        $height = $point->getHeight() && $shifts[2] ? $point->getHeight()->add($shifts[2]) : null;
+
+        return GeographicPoint::create($latitude, $longitude, $height, $to, $point->getCoordinateEpoch());
+    }
+
+    public function applyReverseAdjustment(GeographicPoint $point, Geographic $to): GeographicPoint
+    {
+        $shifts = [new ArcSecond(0), new ArcSecond(0)];
+        $latitude = $point->getLatitude();
+        $longitude = $point->getLongitude();
+
+        do {
+            $prevShifts = $shifts;
+            $shifts = $this->getValues($longitude->getValue(), $latitude->getValue());
+            $latitude = $point->getLatitude()->subtract($shifts[0]);
+            $longitude = $point->getLongitude()->subtract($shifts[1]);
+        } while (abs($shifts[0]->subtract($prevShifts[0])->getValue()) > self::ITERATION_CONVERGENCE && abs($shifts[1]->subtract($prevShifts[1])->getValue()) > self::ITERATION_CONVERGENCE);
+
+        $height = $point->getHeight() && $shifts[2] ? $point->getHeight()->subtract($shifts[2]) : null;
+
+        return GeographicPoint::create($latitude, $longitude, $height, $to, $point->getCoordinateEpoch());
+    }
+}
diff --git a/src/CoordinateOperation/Grid.php b/src/CoordinateOperation/Grid.php
new file mode 100644
index 000000000..94e34655a
--- /dev/null
+++ b/src/CoordinateOperation/Grid.php
@@ -0,0 +1,31 @@
+<?php
+/**
+ * PHPCoord.
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace PHPCoord\CoordinateOperation;
+
+use SplFileObject;
+
+/**
+ * @internal
+ */
+abstract class Grid
+{
+    protected const STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE = 1;
+
+    protected const STORAGE_ORDER_INCREASING_LONGITUDE_DECREASING_LATIITUDE = 2;
+
+    protected const STORAGE_ORDER_DECREASING_LATITUDE_INCREASING_LONGITUDE = 3;
+
+    protected const STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE = 4;
+
+    protected int $storageOrder;
+
+    protected SplFileObject $gridFile;
+
+    abstract public function getValues(float $x, float $y): array;
+}
diff --git a/src/CoordinateOperation/GridProvider.php b/src/CoordinateOperation/GridProvider.php
index 4e15d6d32..6c1081983 100644
--- a/src/CoordinateOperation/GridProvider.php
+++ b/src/CoordinateOperation/GridProvider.php
@@ -8,9 +8,10 @@
 
 namespace PHPCoord\CoordinateOperation;
 
-use SplFileObject;
-
+/**
+ * @internal
+ */
 interface GridProvider
 {
-    public function provideGrid(): SplFileObject;
+    public function provideGrid(): Grid;
 }
diff --git a/src/CoordinateOperation/IGNESHeightGrid.php b/src/CoordinateOperation/IGNESHeightGrid.php
index 1440c8221..035cfd04d 100644
--- a/src/CoordinateOperation/IGNESHeightGrid.php
+++ b/src/CoordinateOperation/IGNESHeightGrid.php
@@ -9,7 +9,6 @@
 namespace PHPCoord\CoordinateOperation;
 
 use function explode;
-use PHPCoord\GeographicPoint;
 use PHPCoord\UnitOfMeasure\Length\Metre;
 use function preg_match;
 use function preg_replace;
@@ -18,43 +17,34 @@
 use function strlen;
 use function trim;
 
-class IGNESHeightGrid extends SplFileObject
+class IGNESHeightGrid extends GeographicGeoidHeightGrid
 {
     use BilinearInterpolation;
 
     private const ITERATION_CONVERGENCE = 0.0001;
 
-    private const STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE = 1;
-
-    private const STORAGE_ORDER_INCREASING_LONGITUDE_DECREASING_LATIITUDE = 2;
-
-    private const STORAGE_ORDER_DECREASING_LATITUDE_INCREASING_LONGITUDE = 3;
-
-    private const STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE = 4;
-
     private bool $coordinatesIncludedInData;
 
     private int $valuesPerCoordinate;
 
     private bool $precisionIncluded;
 
-    private int $storageOrder;
-
     private SplFixedArray $data;
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
         $this->init();
     }
 
-    public function getAdjustment(GeographicPoint $point): Metre
+    /**
+     * @return Metre[]
+     */
+    public function getValues(float $x, float $y): array
     {
-        $latitude = $point->getLatitude()->getValue();
-        $longitude = $point->getLongitude()->getValue();
-        $offset = $this->interpolateBilinear($longitude, $latitude)[0];
+        $shift = $this->interpolate($x, $y)[0];
 
-        return new Metre($offset);
+        return [new Metre($shift)];
     }
 
     protected function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues
@@ -72,7 +62,7 @@ protected function getRecord(int $longitudeIndex, int $latitudeIndex): GridValue
     private function init(): void
     {
         $headerRegexp = '^\s+(-?[\d.]+)\s+(-?[\d.]+)\s+(-?[\d.]+)\s+(-?[\d.]+)\s+([\d.]+)\s+([\d.]+)';
-        $header = $this->fgets();
+        $header = $this->gridFile->fgets();
 
         preg_match('/' . $headerRegexp . '/', $header, $headerParts);
 
@@ -92,7 +82,7 @@ private function init(): void
 
         $this->data = new SplFixedArray($this->numberOfColumns * $this->numberOfRows);
 
-        $rawData = $this->fread($this->getSize() - strlen($header));
+        $rawData = $this->gridFile->fread($this->gridFile->getSize() - strlen($header));
         $values = explode(' ', trim(preg_replace('/\s+/', ' ', $rawData)));
 
         $cursor = 0;
diff --git a/src/CoordinateOperation/IGNFGeocentricTranslationGrid.php b/src/CoordinateOperation/IGNFGeocentricTranslationGrid.php
index ba326f381..a8b146d42 100644
--- a/src/CoordinateOperation/IGNFGeocentricTranslationGrid.php
+++ b/src/CoordinateOperation/IGNFGeocentricTranslationGrid.php
@@ -11,16 +11,15 @@
 use function abs;
 use PHPCoord\CoordinateReferenceSystem\Geographic;
 use PHPCoord\GeographicPoint;
-use PHPCoord\UnitOfMeasure\Angle\Degree;
 use PHPCoord\UnitOfMeasure\Length\Metre;
 
-class IGNFGeocentricTranslationGrid extends IGNFGrid
+class IGNFGeocentricTranslationGrid extends GeographicGrid
 {
-    private const ITERATION_CONVERGENCE = 0.0001;
+    use IGNFGrid;
 
     public function applyForwardAdjustment(GeographicPoint $point, Geographic $to): GeographicPoint
     {
-        [$tx, $ty, $tz] = $this->getAdjustment($point->getLatitude()->asDegrees(), $point->getLongitude()->asDegrees());
+        [$tx, $ty, $tz] = $this->getValues($point->getLongitude()->asDegrees()->getValue(), $point->getLatitude()->asDegrees()->getValue());
 
         return $point->geocentricTranslation(
             $to,
@@ -38,7 +37,7 @@ public function applyReverseAdjustment(GeographicPoint $point, Geographic $to):
 
         do {
             $prevAdjustment = $adjustment;
-            $adjustment = $this->getAdjustment($latitude->asDegrees(), $longitude->asDegrees());
+            $adjustment = $this->getValues($longitude->asDegrees()->getValue(), $latitude->asDegrees()->getValue());
             $newPoint = $point->geocentricTranslation(
                 $to,
                 $adjustment[0]->multiply(-1),
@@ -56,9 +55,9 @@ public function applyReverseAdjustment(GeographicPoint $point, Geographic $to):
     /**
      * @return Metre[]
      */
-    private function getAdjustment(Degree $latitude, Degree $longitude): array
+    public function getValues(float $x, float $y): array
     {
-        $offsets = $this->interpolateBilinear($longitude->getValue(), $latitude->getValue());
+        $offsets = $this->interpolate($x, $y);
 
         return [new Metre($offsets[0]), new Metre($offsets[1]), new Metre($offsets[2])];
     }
diff --git a/src/CoordinateOperation/IGNFGrid.php b/src/CoordinateOperation/IGNFGrid.php
index 9d4dd2cd6..86ce73f76 100644
--- a/src/CoordinateOperation/IGNFGrid.php
+++ b/src/CoordinateOperation/IGNFGrid.php
@@ -24,35 +24,19 @@
 use function strlen;
 use function trim;
 
-abstract class IGNFGrid extends SplFileObject
+trait IGNFGrid
 {
     use BilinearInterpolation;
 
-    private const ITERATION_CONVERGENCE = 0.0001;
-
-    private const STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE = 1;
-
-    private const STORAGE_ORDER_INCREASING_LONGITUDE_DECREASING_LATIITUDE = 2;
-
-    private const STORAGE_ORDER_DECREASING_LATITUDE_INCREASING_LONGITUDE = 3;
-
-    private const STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE = 4;
-
-    private bool $coordinatesIncludedInData;
-
     private int $valuesPerCoordinate;
 
-    private bool $precisionIncluded;
-
-    private int $storageOrder;
-
     private SplFixedArray $data;
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
 
-        match ($this->getExtension()) {
+        match ($this->gridFile->getExtension()) {
             'txt' => $this->initTxt(),
             'mnt', 'tac' => $this->initMntOrTac(),
         };
@@ -77,10 +61,10 @@ private function initTxt(): void
     {
         $this->valuesPerCoordinate = 3;
 
-        $header0 = $this->fgets();
-        $header1 = $this->fgets();
-        $header2 = $this->fgets();
-        $header3 = $this->fgets();
+        $header0 = $this->gridFile->fgets();
+        $header1 = $this->gridFile->fgets();
+        $header2 = $this->gridFile->fgets();
+        $header3 = $this->gridFile->fgets();
 
         $interpolationMethod = trim(str_replace('GR3D2', '', $header2));
         assert($interpolationMethod === 'INTERPOLATION BILINEAIRE');
@@ -98,20 +82,20 @@ private function initTxt(): void
 
         $this->data = new SplFixedArray($this->numberOfColumns * $this->numberOfRows);
         for ($i = 0, $numValues = $this->numberOfColumns * $this->numberOfRows; $i < $numValues; ++$i) {
-            $rowData = explode(' ', trim(preg_replace('/ +/', ' ', $this->fgets())));
+            $rowData = explode(' ', trim(preg_replace('/ +/', ' ', $this->gridFile->fgets())));
             $wantedData = array_slice($rowData, 3, 3); // ignore weird first fixed value, coordinates, precision and map sheet
             $wantedData = array_map(static function (string $value) {return (float) ($value); }, $wantedData);
             $this->data[$i] = $wantedData;
         }
 
-        $this->fgets();
-        assert($this->eof());
+        $this->gridFile->fgets();
+        assert($this->gridFile->eof());
     }
 
     private function initMntOrTac(): void
     {
         $fixedHeaderRegexp = '^(-?[\d.]+) (-?[\d.]+) (-?[\d.]+) (-?[\d.]+) ([\d.]+) ([\d.]+) ([1-4]) ([01]) (\d) ([01]) ';
-        $header = $this->fgets();
+        $header = $this->gridFile->fgets();
 
         preg_match('/' . $fixedHeaderRegexp . '/', $header, $fixedHeaderParts);
 
@@ -124,9 +108,9 @@ private function initMntOrTac(): void
         $this->numberOfColumns = (int) (string) (($this->endX - $this->startX) / $this->columnGridInterval) + 1;
         $this->numberOfRows = (int) (string) (($this->endY - $this->startY) / $this->rowGridInterval) + 1;
         $this->storageOrder = (int) $fixedHeaderParts[7];
-        $this->coordinatesIncludedInData = (bool) $fixedHeaderParts[8];
+        $coordinatesIncludedInData = (bool) $fixedHeaderParts[8];
         $this->valuesPerCoordinate = (int) $fixedHeaderParts[9];
-        $this->precisionIncluded = (bool) $fixedHeaderParts[10];
+        $precisionIncluded = (bool) $fixedHeaderParts[10];
 
         preg_match('/' . $fixedHeaderRegexp . str_repeat('(-?[\d.]+) ', $this->valuesPerCoordinate) . '(.*)$/', $header, $fullHeaderParts);
 
@@ -140,12 +124,12 @@ private function initMntOrTac(): void
 
         $this->data = new SplFixedArray($this->numberOfColumns * $this->numberOfRows);
 
-        $rawData = $this->fread($this->getSize() - strlen($header));
+        $rawData = $this->gridFile->fread($this->gridFile->getSize() - strlen($header));
         $values = explode(' ', trim(preg_replace('/\s+/', ' ', $rawData)));
 
         $cursor = 0;
         for ($i = 0, $numValues = $this->numberOfColumns * $this->numberOfRows; $i < $numValues; ++$i) {
-            if ($this->coordinatesIncludedInData) {
+            if ($coordinatesIncludedInData) {
                 $cursor += 2;
             }
 
@@ -157,12 +141,12 @@ private function initMntOrTac(): void
 
             $this->data[$i] = $rowData;
 
-            if ($this->precisionIncluded) {
+            if ($precisionIncluded) {
                 ++$cursor;
             }
         }
 
-        $this->fgets();
-        assert($this->eof());
+        $this->gridFile->fgets();
+        assert($this->gridFile->eof());
     }
 }
diff --git a/src/CoordinateOperation/IGNFHeightGrid.php b/src/CoordinateOperation/IGNFHeightGrid.php
index 65b13a917..3903d186c 100644
--- a/src/CoordinateOperation/IGNFHeightGrid.php
+++ b/src/CoordinateOperation/IGNFHeightGrid.php
@@ -8,19 +8,19 @@
 
 namespace PHPCoord\CoordinateOperation;
 
-use PHPCoord\GeographicPoint;
 use PHPCoord\UnitOfMeasure\Length\Metre;
 
-class IGNFHeightGrid extends IGNFGrid
+class IGNFHeightGrid extends GeographicGeoidHeightGrid
 {
-    private const ITERATION_CONVERGENCE = 0.0001;
+    use IGNFGrid;
 
-    public function getAdjustment(GeographicPoint $point): Metre
+    /**
+     * @return Metre[]
+     */
+    public function getValues(float $x, float $y): array
     {
-        $latitude = $point->getLatitude()->getValue();
-        $longitude = $point->getLongitude()->getValue();
-        $offset = $this->interpolateBilinear($longitude, $latitude)[0];
+        $shift = $this->interpolate($x, $y)[0];
 
-        return new Metre($offset);
+        return [new Metre($shift)];
     }
 }
diff --git a/src/CoordinateOperation/NADCON5Grid.php b/src/CoordinateOperation/NADCON5Grid.php
index 422ce3801..c4b4e6c53 100644
--- a/src/CoordinateOperation/NADCON5Grid.php
+++ b/src/CoordinateOperation/NADCON5Grid.php
@@ -8,12 +8,11 @@
 
 namespace PHPCoord\CoordinateOperation;
 
-use PHPCoord\GeographicPoint;
 use SplFileObject;
 use UnexpectedValueException;
 use function unpack;
 
-class NADCON5Grid extends SplFileObject
+class NADCON5Grid extends Grid
 {
     use BiquadraticInterpolation;
 
@@ -21,7 +20,7 @@ class NADCON5Grid extends SplFileObject
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
 
         $header = $this->getHeader();
         $this->startX = $header['xlonsw'];
@@ -37,118 +36,38 @@ public function __construct($filename)
         };
     }
 
-    public function getForwardAdjustment(GeographicPoint $point): float
-    {
-        return $this->getAdjustment($point->getLatitude()->asDegrees()->getValue(), $point->getLongitude()->asDegrees()->getValue());
-    }
-
-    /**
-     * Converted from NOAA FORTRAN.
-     */
-    private function getAdjustment(float $latitude, float $longitude): float
-    {
-        if ($longitude < 0) {
-            $longitude += 360; // NADCON5 uses 0 = 360 = Greenwich
-        }
-
-        // Method:
-        // Fit a 3x3 window over the random point. The closest
-        // 2x2 points will surround the point. But based on which
-        // quadrant of that 2x2 cell in which the point falls, the
-        // 3x3 window could extend NW, NE, SW or SE from the 2x2 cell.
-
-        // Find which column should be LEAST when fitting
-        // a 3x3 window around $longitude.
-        $diflo = ($longitude - $this->startX);
-        $ratlo = $diflo / ($this->columnGridInterval / 2);
-        $ilo = (int) ($ratlo) + 1;
-        if ($ilo % 2 != 0) {
-            $xIndex = ($ilo + 1) / 2 - 1;
-        } else {
-            $xIndex = ($ilo) / 2;
-        }
-
-        // Fix any edge overlaps
-        if ($xIndex < 1) {
-            $xIndex = 1;
-        }
-        if ($xIndex > $this->numberOfColumns - 2) {
-            $xIndex = $this->numberOfColumns - 2;
-        }
-
-        // Find which row should be LEAST when fitting
-        // a 3x3 window around $latitude.
-        $difla = ($latitude - $this->startY);
-        $ratla = $difla / ($this->rowGridInterval / 2);
-        $ila = (int) ($ratla) + 1;
-        if ($ila % 2 != 0) {
-            $yIndex = ($ila + 1) / 2 - 1;
-        } else {
-            $yIndex = ($ila) / 2;
-        }
-
-        // Fix any edge overlaps
-        if ($yIndex < 1) {
-            $yIndex = 1;
-        }
-        if ($yIndex > $this->numberOfRows - 2) {
-            $yIndex = $this->numberOfRows - 2;
-        }
-
-        // In the range of 0(westernmost) to
-        // 2(easternmost) col, where is our
-        // random lon value? That is, x must
-        // be real and fall between 0 and 2.
-        $x = ($longitude - $this->columnGridInterval * ($xIndex - 1) - $this->startX) / $this->columnGridInterval;
-
-        // In the range of 0(southernmost) to
-        // 2(northernmost) row, where is our
-        // random lat value? That is, x must
-        // be real and fall between 0 and 2.
-        $y = ($latitude - $this->rowGridInterval * ($yIndex - 1) - $this->startY) / $this->rowGridInterval;
-
-        $corners = [
-            'lowerLeft' => $this->getRecord($xIndex, $yIndex),
-            'lowerCentre' => $this->getRecord($xIndex + 1, $yIndex),
-            'lowerRight' => $this->getRecord($xIndex + 2, $yIndex),
-            'middleLeft' => $this->getRecord($xIndex, $yIndex + 1),
-            'middleCentre' => $this->getRecord($xIndex + 1, $yIndex + 1),
-            'middleRight' => $this->getRecord($xIndex + 2, $yIndex + 1),
-            'upperLeft' => $this->getRecord($xIndex, $yIndex + 2),
-            'upperCentre' => $this->getRecord($xIndex + 1, $yIndex + 2),
-            'upperRight' => $this->getRecord($xIndex + 2, $yIndex + 2),
-        ];
-
-        //Interpolate value at lower row
-        $y0 = $this->interpolateQuadratic($x, $corners['lowerLeft'], $corners['lowerCentre'], $corners['lowerRight']);
-        //Interpolate value at middle row
-        $y1 = $this->interpolateQuadratic($x, $corners['middleLeft'], $corners['middleCentre'], $corners['middleRight']);
-        //Interpolate value at upper row
-        $y2 = $this->interpolateQuadratic($x, $corners['upperLeft'], $corners['upperCentre'], $corners['upperRight']);
-
-        //Interpolate between rows
-        return $this->interpolateQuadratic($y, $y0, $y1, $y2);
-    }
-
-    public function getRecord(int $longitudeIndex, int $latitudeIndex): float
+    protected function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues
     {
         $startBytes = 52;
         $dataTypeBytes = $this->gridDataType === 'n' ? 2 : 4;
         $recordLength = 4 + $this->numberOfColumns * $dataTypeBytes + 4;
 
-        $this->fseek($startBytes + $recordLength * ($latitudeIndex - 1));
-        $rawRow = $this->fread($recordLength);
+        $this->gridFile->fseek($startBytes + $recordLength * $latitudeIndex);
+        $rawRow = $this->gridFile->fread($recordLength);
         $row = unpack("Gstartbuffer/{$this->gridDataType}{$this->numberOfColumns}lon/Gendbuffer", $rawRow);
 
-        return $row['lon' . ($longitudeIndex)];
+        return new GridValues(
+            $longitudeIndex * $this->columnGridInterval + $this->startX,
+            $latitudeIndex * $this->rowGridInterval + $this->startY,
+            [$row['lon' . ($longitudeIndex + 1)]]
+        );
     }
 
     private function getHeader(): array
     {
-        $this->fseek(0);
-        $rawData = $this->fread(52);
+        $this->gridFile->fseek(0);
+        $rawData = $this->gridFile->fread(52);
         $data = unpack('Gstartbuffer/Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon/Nikind/Gendbuffer/', $rawData);
 
         return $data;
     }
+
+    public function getValues(float $x, float $y): array
+    {
+        if ($x < 0) {
+            $x += 360; // NADCON5 uses 0 = 360 = Greenwich
+        }
+
+        return $this->interpolate($x, $y);
+    }
 }
diff --git a/src/CoordinateOperation/NADCON5Grids.php b/src/CoordinateOperation/NADCON5Grids.php
new file mode 100644
index 000000000..bb6052271
--- /dev/null
+++ b/src/CoordinateOperation/NADCON5Grids.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * PHPCoord.
+ *
+ * @author Doug Wright
+ */
+declare(strict_types=1);
+
+namespace PHPCoord\CoordinateOperation;
+
+use PHPCoord\UnitOfMeasure\Angle\ArcSecond;
+use PHPCoord\UnitOfMeasure\Length\Metre;
+
+class NADCON5Grids extends GeographicGrid
+{
+    private NADCON5Grid $longitudeGrid;
+    private NADCON5Grid $latitudeGrid;
+    private ?NADCON5Grid $ellipsoidHeightGrid;
+
+    public function __construct(NADCON5Grid $longitudeGrid, NADCON5Grid $latitudeGrid, ?NADCON5Grid $ellipsoidHeightGrid)
+    {
+        $this->longitudeGrid = $longitudeGrid;
+        $this->latitudeGrid = $latitudeGrid;
+        $this->ellipsoidHeightGrid = $ellipsoidHeightGrid;
+    }
+
+    public function getValues(float $x, float $y): array
+    {
+        $latitudeShift = new ArcSecond($this->latitudeGrid->getValues($x, $y)[0]);
+        $longitudeShift = new ArcSecond($this->longitudeGrid->getValues($x, $y)[0]);
+        $heightShift = $this->ellipsoidHeightGrid ? new Metre($this->ellipsoidHeightGrid->getValues($x, $y)[0]) : null;
+
+        return [$latitudeShift, $longitudeShift, $heightShift];
+    }
+}
diff --git a/src/CoordinateOperation/NTv2Grid.php b/src/CoordinateOperation/NTv2Grid.php
index 49a07e848..2a57c5e9f 100644
--- a/src/CoordinateOperation/NTv2Grid.php
+++ b/src/CoordinateOperation/NTv2Grid.php
@@ -8,21 +8,16 @@
 
 namespace PHPCoord\CoordinateOperation;
 
-use function abs;
 use function assert;
-use PHPCoord\CoordinateReferenceSystem\Geographic;
-use PHPCoord\GeographicPoint;
-use PHPCoord\UnitOfMeasure\Angle\Angle;
 use PHPCoord\UnitOfMeasure\Angle\ArcSecond;
 use function round;
 use SplFileObject;
 use function unpack;
 use function usort;
 
-class NTv2Grid extends SplFileObject
+class NTv2Grid extends GeographicGrid
 {
     private const RECORD_SIZE = 16;
-    private const ITERATION_CONVERGENCE = 0.0001;
     private const FLAG_WITHIN_LIMITS = 1;
     private const FLAG_ON_UPPER_LATITUDE = 2;
     private const FLAG_ON_UPPER_LONGITUDE = 3;
@@ -36,58 +31,33 @@ class NTv2Grid extends SplFileObject
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
+        $this->storageOrder = self::STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE;
 
         $this->readHeader();
     }
 
-    public function applyForwardAdjustment(GeographicPoint $point, Geographic $to): GeographicPoint
-    {
-        $adjustment = $this->getAdjustment($point->getLatitude(), $point->getLongitude());
-
-        $latitude = $point->getLatitude()->add($adjustment[0]);
-        $longitude = $point->getLongitude()->add($adjustment[1]);
-
-        return GeographicPoint::create($latitude, $longitude, $point->getHeight(), $to, $point->getCoordinateEpoch());
-    }
-
-    public function applyReverseAdjustment(GeographicPoint $point, Geographic $to): GeographicPoint
-    {
-        $adjustment = [new ArcSecond(0), new ArcSecond(0)];
-        $latitude = $point->getLatitude();
-        $longitude = $point->getLongitude();
-
-        do {
-            $prevAdjustment = $adjustment;
-            $adjustment = $this->getAdjustment($latitude, $longitude);
-            $latitude = $point->getLatitude()->subtract($adjustment[0]);
-            $longitude = $point->getLongitude()->subtract($adjustment[1]);
-        } while (abs($adjustment[0]->subtract($prevAdjustment[0])->getValue()) > self::ITERATION_CONVERGENCE && abs($adjustment[1]->subtract($prevAdjustment[1])->getValue()) > self::ITERATION_CONVERGENCE);
-
-        return GeographicPoint::create($latitude, $longitude, $point->getHeight(), $to, $point->getCoordinateEpoch());
-    }
-
     /**
      * @return ArcSecond[]
      */
-    private function getAdjustment(Angle $latitude, Angle $longitude): array
+    public function getValues(float $x, float $y): array
     {
         // NTv2 is longitude positive *west*
-        $longitude = $longitude->multiply(-1);
+        $x *= -1;
 
-        $latitudeAsSeconds = Angle::convert($latitude, Angle::EPSG_ARC_SECOND)->getValue();
-        $longitudeAsSeconds = Angle::convert($longitude, Angle::EPSG_ARC_SECOND)->getValue();
-        $gridToUse = $this->determineBestGrid($latitudeAsSeconds, $longitudeAsSeconds);
+        // NTv2 is in seconds, not degrees
+        $x *= 3600;
+        $y *= 3600;
 
-        $offsets = $gridToUse->interpolateBilinear($longitudeAsSeconds, $latitudeAsSeconds);
+        $gridToUse = $this->determineBestGrid($x, $y);
 
-        return [new ArcSecond($offsets[0]), new ArcSecond(-$offsets[1])]; // NTv2 is longitude positive *west*
+        return $gridToUse->getValues($x, $y);
     }
 
     private function readHeader(): void
     {
-        $this->fseek(0);
-        $rawData = $this->fread(11 * self::RECORD_SIZE);
+        $this->gridFile->fseek(0);
+        $rawData = $this->gridFile->fread(11 * self::RECORD_SIZE);
         if (unpack('VNUM_OREC', $rawData, 8)['NUM_OREC'] !== 11) {
             $this->integerFormatChar = 'N';
             $this->doubleFormatChar = 'E';
@@ -100,8 +70,8 @@ private function readHeader(): void
 
         $subFileStart = 11 * self::RECORD_SIZE;
         for ($i = 0; $i < $data['NUM_FILE']; ++$i) {
-            $this->fseek($subFileStart);
-            $subFileRawData = $this->fread(11 * self::RECORD_SIZE);
+            $this->gridFile->fseek($subFileStart);
+            $subFileRawData = $this->gridFile->fread(11 * self::RECORD_SIZE);
             $subFileData = unpack("A8/A8SUB_NAME/A8/A8PARENT/A8/A8CREATED/A8/A8UPDATED/A8/{$this->doubleFormatChar}S_LAT/A8/{$this->doubleFormatChar}N_LAT/A8/{$this->doubleFormatChar}E_LONG/A8/{$this->doubleFormatChar}W_LONG/A8/{$this->doubleFormatChar}LAT_INC/A8/{$this->doubleFormatChar}LONG_INC/A8/{$this->integerFormatChar}GS_COUNT/x4", $subFileRawData);
             $subFileData['offsetStart'] = $subFileStart;
 
@@ -116,7 +86,7 @@ private function readHeader(): void
         }
     }
 
-    private function determineBestGrid(float $latitude, float $longitude): NTv2SubGrid
+    private function determineBestGrid(float $longitude, float $latitude): NTv2SubGrid
     {
         $possibleGrids = [];
         foreach ($this->subFileMetaData as $subFileMetaDatum) {
@@ -138,7 +108,7 @@ private function determineBestGrid(float $latitude, float $longitude): NTv2SubGr
         $gridToUse = $possibleGrids[0][1];
 
         return new NTv2SubGrid(
-            $this->getPathname(),
+            $this->gridFile->getPathname(),
             $gridToUse['offsetStart'],
             $gridToUse['S_LAT'],
             $gridToUse['N_LAT'],
diff --git a/src/CoordinateOperation/NTv2SubGrid.php b/src/CoordinateOperation/NTv2SubGrid.php
index 1feec5d59..c36ce0690 100644
--- a/src/CoordinateOperation/NTv2SubGrid.php
+++ b/src/CoordinateOperation/NTv2SubGrid.php
@@ -8,10 +8,11 @@
 
 namespace PHPCoord\CoordinateOperation;
 
+use PHPCoord\UnitOfMeasure\Angle\ArcSecond;
 use SplFileObject;
 use function unpack;
 
-class NTv2SubGrid extends SplFileObject
+class NTv2SubGrid extends Grid
 {
     use BilinearInterpolation;
 
@@ -31,7 +32,7 @@ public function __construct(
         float $longitudeInterval,
         string $floatFormatChar
     ) {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
         $this->offsetStart = $offsetStart;
         $this->startX = $minLongitude;
         $this->endX = $maxLongitude;
@@ -44,12 +45,22 @@ public function __construct(
         $this->numberOfRows = (int) (($this->endY - $this->startY) / $this->rowGridInterval);
     }
 
-    public function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues
+    /**
+     * @return ArcSecond[]
+     */
+    public function getValues(float $x, float $y): array
+    {
+        $shifts = $this->interpolate($x, $y);
+
+        return [new ArcSecond($shifts[0]), new ArcSecond(-$shifts[1])]; // NTv2 is longitude positive *west*
+    }
+
+    protected function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues
     {
         $recordIndex = $latitudeIndex * ($this->numberOfColumns + 1) + $longitudeIndex;
         $recordOffset = $this->offsetStart + ((11 + $recordIndex) * self::RECORD_SIZE);
-        $this->fseek($recordOffset);
-        $rawRecord = $this->fread(self::RECORD_SIZE);
+        $this->gridFile->fseek($recordOffset);
+        $rawRecord = $this->gridFile->fread(self::RECORD_SIZE);
         $shifts = unpack("{$this->floatFormatChar}LATITUDE_SHIFT/{$this->floatFormatChar}LONGITUDE_SHIFT/{$this->floatFormatChar}LATITUDE_ACCURACY/{$this->floatFormatChar}LONGITUDE_ACCURACY", $rawRecord);
 
         return new GridValues(
diff --git a/src/CoordinateOperation/OSTNOSGM15Grid.php b/src/CoordinateOperation/OSTNOSGM15Grid.php
index 067aa17b8..3264fe2eb 100644
--- a/src/CoordinateOperation/OSTNOSGM15Grid.php
+++ b/src/CoordinateOperation/OSTNOSGM15Grid.php
@@ -16,7 +16,7 @@
 use PHPCoord\UnitOfMeasure\Length\Metre;
 use SplFileObject;
 
-class OSTNOSGM15Grid extends SplFileObject
+class OSTNOSGM15Grid extends Grid
 {
     use BilinearInterpolation;
 
@@ -24,7 +24,7 @@ class OSTNOSGM15Grid extends SplFileObject
 
     public function __construct($filename)
     {
-        parent::__construct($filename);
+        $this->gridFile = new SplFileObject($filename);
 
         $this->startX = 0;
         $this->startY = 0;
@@ -36,10 +36,10 @@ public function __construct($filename)
 
     public function applyForwardHorizontalAdjustment(ProjectedPoint $point): ProjectedPoint
     {
-        $adjustment = $this->getAdjustment($point->getEasting()->asMetres(), $point->getNorthing()->asMetres());
+        $adjustment = $this->getValues($point->getEasting()->asMetres()->getValue(), $point->getNorthing()->asMetres()->getValue());
 
-        $easting = $point->getEasting()->add(new Metre($adjustment[0]));
-        $northing = $point->getNorthing()->add(new Metre($adjustment[1]));
+        $easting = $point->getEasting()->add($adjustment[0]);
+        $northing = $point->getNorthing()->add($adjustment[1]);
 
         return ProjectedPoint::createFromEastingNorthing($easting, $northing, Projected::fromSRID(Projected::EPSG_OSGB36_BRITISH_NATIONAL_GRID), $point->getCoordinateEpoch());
     }
@@ -54,40 +54,43 @@ public function applyReverseHorizontalAdjustment(ProjectedPoint $point): Project
             $osgb36NationalGrid->getBoundingArea()
         );
 
-        $adjustment = [0, 0];
+        $adjustment = [new Metre(0), new Metre(0)];
         $easting = $point->getEasting();
         $northing = $point->getNorthing();
 
         do {
             $prevAdjustment = $adjustment;
-            $adjustment = $this->getAdjustment($easting->asMetres(), $northing->asMetres());
-            $easting = $point->getEasting()->subtract(new Metre($adjustment[0]));
-            $northing = $point->getNorthing()->subtract(new Metre($adjustment[1]));
-        } while (abs($adjustment[0] - $prevAdjustment[0]) > self::ITERATION_CONVERGENCE && abs($adjustment[1] - $prevAdjustment[1]) > self::ITERATION_CONVERGENCE);
+            $adjustment = $this->getValues($easting->asMetres()->getValue(), $northing->asMetres()->getValue());
+            $easting = $point->getEasting()->subtract($adjustment[0]);
+            $northing = $point->getNorthing()->subtract($adjustment[1]);
+        } while (abs($adjustment[0]->subtract($prevAdjustment[0])->getValue()) > self::ITERATION_CONVERGENCE && abs($adjustment[1]->subtract($prevAdjustment[1])->getValue()) > self::ITERATION_CONVERGENCE);
 
         return ProjectedPoint::createFromEastingNorthing($easting, $northing, $etrs89NationalGrid, $point->getCoordinateEpoch());
     }
 
-    public function getVerticalAdjustment(ProjectedPoint $point): Metre
+    public function getHeightAdjustment(ProjectedPoint $point): Metre
     {
-        $adjustment = $this->getAdjustment($point->getEasting()->asMetres(), $point->getNorthing()->asMetres());
+        $adjustment = $this->getValues($point->getEasting()->asMetres()->getValue(), $point->getNorthing()->asMetres()->getValue());
 
-        return new Metre($adjustment[2]);
+        return $adjustment[2];
     }
 
-    private function getAdjustment(Metre $easting, Metre $northing): array
+    /**
+     * @return Metre[]
+     */
+    public function getValues(float $x, float $y): array
     {
-        $offsets = $this->interpolateBilinear($easting->getValue(), $northing->getValue());
+        $offsets = $this->interpolate($x, $y);
 
-        return $offsets;
+        return [new Metre($offsets[0]), new Metre($offsets[1]), new Metre($offsets[2])];
     }
 
     private function getRecord(int $eastIndex, int $northIndex): GridValues
     {
         $record = $northIndex * 701 + $eastIndex + 1;
 
-        $this->seek($record);
-        $rawData = $this->fgetcsv();
+        $this->gridFile->seek($record);
+        $rawData = $this->gridFile->fgetcsv();
 
         return new GridValues((float) $rawData[1], (float) $rawData[2], [(float) $rawData[3], (float) $rawData[4], (float) $rawData[5]]);
     }
diff --git a/src/EPSG/Import/EPSGCodegenFromDataImport.php b/src/EPSG/Import/EPSGCodegenFromDataImport.php
index f597d5460..fda956223 100644
--- a/src/EPSG/Import/EPSGCodegenFromDataImport.php
+++ b/src/EPSG/Import/EPSGCodegenFromDataImport.php
@@ -1262,7 +1262,7 @@ public function generateDataCoordinateOperations(): void
                         CASE WHEN pu.param_sign_reversal = 'Yes' THEN 1 ELSE 0 END AS reverses
                     FROM epsg_coordoperationparamvalue pv
                     JOIN epsg_coordoperationparamusage pu ON pv.coord_op_method_code = pu.coord_op_method_code AND pv.parameter_code = pu.parameter_code
-                    JOIN epsg_coordoperationparam p ON pv.parameter_code = p.parameter_code
+                    JOIN epsg_coordoperationparam p ON pv.parameter_code = p.parameter_code AND p.parameter_code NOT IN (1048, 1062)
                     WHERE operation_code = '{$operation}'
                     GROUP BY pv.coord_op_code, p.parameter_code
                     ORDER BY pu.sort_order
@@ -1271,7 +1271,7 @@ public function generateDataCoordinateOperations(): void
             $paramsResult = $this->sqlite->query($paramsSql);
             while ($paramsRow = $paramsResult->fetchArray(SQLITE3_ASSOC)) {
                 unset($paramsRow['operation_code']);
-                $paramsRow['name'] = self::camelCase($paramsRow['name']);
+                $paramsRow['name'] = self::makeParamName($paramsRow['name']);
                 $paramsRow['reverses'] = (bool) $paramsRow['reverses'];
                 if (in_array($paramsRow['parameter_code'], [8659, 8660, 1037, 1048, 8661, 8662], true)) {
                     $paramsRow['value'] = 'urn:ogc:def:crs:EPSG::' . $paramsRow['value'];
@@ -1288,9 +1288,7 @@ public function generateDataCoordinateOperations(): void
                             'latitudeDifferenceFile',
                             'longitudeDifferenceFile',
                             'ellipsoidalHeightDifferenceFile',
-                            'latitudeAndLongitudeDifferenceFile',
-                            'geocentricTranslationFile',
-                            'verticalOffsetFile',
+                            'offsetsFile',
                         ],
                         true
                     )
@@ -1461,13 +1459,17 @@ public function generateExtents(): void
         echo 'done' . PHP_EOL;
     }
 
-    protected static function camelCase(string $string): string
+    protected static function makeParamName(string $string): string
     {
         $string = str_replace([' ', '-', '(', ')', '"'], '', ucwords($string, ' -()"'));
         if (!preg_match('/^(EPSG|[ABC][uv\d])/', $string)) {
             $string = lcfirst($string);
         }
 
+        if (in_array($string, ['latitudeAndLongitudeDifferenceFile', 'geocentricTranslationFile', 'verticalOffsetFile'], true)) {
+            $string = 'offsetsFile';
+        }
+
         return $string;
     }
 }
diff --git a/src/GeographicPoint.php b/src/GeographicPoint.php
index 8e108c38e..f29532934 100644
--- a/src/GeographicPoint.php
+++ b/src/GeographicPoint.php
@@ -30,13 +30,11 @@
 use PHPCoord\CoordinateOperation\ComplexNumber;
 use PHPCoord\CoordinateOperation\ConvertiblePoint;
 use PHPCoord\CoordinateOperation\GeocentricValue;
+use PHPCoord\CoordinateOperation\GeographicGeoidHeightGrid;
+use PHPCoord\CoordinateOperation\GeographicGrid;
 use PHPCoord\CoordinateOperation\GeographicValue;
-use PHPCoord\CoordinateOperation\GTXGrid;
-use PHPCoord\CoordinateOperation\IGNESHeightGrid;
-use PHPCoord\CoordinateOperation\IGNFGeocentricTranslationGrid;
-use PHPCoord\CoordinateOperation\IGNFHeightGrid;
 use PHPCoord\CoordinateOperation\NADCON5Grid;
-use PHPCoord\CoordinateOperation\NTv2Grid;
+use PHPCoord\CoordinateOperation\NADCON5Grids;
 use PHPCoord\CoordinateOperation\OSTNOSGM15Grid;
 use PHPCoord\CoordinateReferenceSystem\Compound;
 use PHPCoord\CoordinateReferenceSystem\Geocentric;
@@ -2117,8 +2115,7 @@ public function OSTN15(
      */
     public function geographic3DTo2DPlusGravityHeightOSGM15(
         Compound $to,
-        OSTNOSGM15Grid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        OSTNOSGM15Grid $geoidHeightCorrectionModelFile
     ): CompoundPoint {
         $osgb36NationalGrid = Projected::fromSRID(Projected::EPSG_OSGB36_BRITISH_NATIONAL_GRID);
         $etrs89NationalGrid = new Projected(
@@ -2139,7 +2136,7 @@ public function geographic3DTo2DPlusGravityHeightOSGM15(
         );
 
         $verticalPoint = VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getVerticalAdjustment($projected)),
+            $this->height->subtract($geoidHeightCorrectionModelFile->getHeightAdjustment($projected)),
             $to->getVertical(),
             $this->getCoordinateEpoch()
         );
@@ -2172,93 +2169,18 @@ public function geographic3DToGravityHeightOSGM15(
         $projected = $this->transverseMercator($etrs89NationalGrid, new Degree(49), new Degree(-2), new Unity(0.9996012717), new Metre(400000), new Metre(-100000));
 
         return VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getVerticalAdjustment($projected)),
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geog3D to Geog2D+GravityRelatedHeight (gtx).
-     */
-    public function geographic3DTo2DPlusGravityHeightGTX(
-        Compound $to,
-        GTXGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
-    ): CompoundPoint {
-        $horizontalPoint = self::create(
-            $this->latitude,
-            $this->longitude,
-            null,
-            $to->getHorizontal(),
-            $this->getCoordinateEpoch()
-        );
-
-        $verticalPoint = VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
-            $to->getVertical(),
-            $this->getCoordinateEpoch()
-        );
-
-        return CompoundPoint::create(
-            $horizontalPoint,
-            $verticalPoint,
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geographic3D to GravityRelatedHeight (gtx).
-     */
-    public function geographic3DToGravityHeightGTX(
-        Vertical $to,
-        GTXGrid $geoidHeightCorrectionModelFile
-    ): VerticalPoint {
-        return VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geog3D to Geog2D+GravityRelatedHeight (IGNES).
-     */
-    public function geographic3DTo2DPlusGravityHeightIGNES(
-        Compound $to,
-        IGNESHeightGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
-    ): CompoundPoint {
-        $horizontalPoint = self::create(
-            $this->latitude,
-            $this->longitude,
-            null,
-            $to->getHorizontal(),
-            $this->getCoordinateEpoch()
-        );
-
-        $verticalPoint = VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
-            $to->getVertical(),
-            $this->getCoordinateEpoch()
-        );
-
-        return CompoundPoint::create(
-            $horizontalPoint,
-            $verticalPoint,
+            $this->height->subtract($geoidHeightCorrectionModelFile->getHeightAdjustment($projected)),
             $to,
             $this->getCoordinateEpoch()
         );
     }
 
     /**
-     * Geog3D to Geog2D+GravityRelatedHeight (IGNF).
+     * Geog3D to Geog2D+GravityRelatedHeight.
      */
-    public function geographic3DTo2DPlusGravityHeightIGNF(
+    public function geographic3DTo2DPlusGravityHeightFromGrid(
         Compound $to,
-        IGNFHeightGrid $geoidHeightCorrectionModelFile,
-        string $EPSGCodeForInterpolationCRS
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ): CompoundPoint {
         $horizontalPoint = self::create(
             $this->latitude,
@@ -2269,7 +2191,7 @@ public function geographic3DTo2DPlusGravityHeightIGNF(
         );
 
         $verticalPoint = VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
+            $this->height->subtract($geoidHeightCorrectionModelFile->getHeightAdjustment($this)),
             $to->getVertical(),
             $this->getCoordinateEpoch()
         );
@@ -2283,28 +2205,14 @@ public function geographic3DTo2DPlusGravityHeightIGNF(
     }
 
     /**
-     * Geographic3D to GravityRelatedHeight (IGNES).
+     * Geographic3D to GravityRelatedHeight.
      */
-    public function geographic3DToGravityHeightIGNES(
+    public function geographic3DToGravityHeightFromGrid(
         Vertical $to,
-        IGNESHeightGrid $geoidHeightCorrectionModelFile
+        GeographicGeoidHeightGrid $geoidHeightCorrectionModelFile
     ): VerticalPoint {
         return VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
-            $to,
-            $this->getCoordinateEpoch()
-        );
-    }
-
-    /**
-     * Geographic3D to GravityRelatedHeight (IGNF).
-     */
-    public function geographic3DToGravityHeightIGNF(
-        Vertical $to,
-        IGNFHeightGrid $geoidHeightCorrectionModelFile
-    ): VerticalPoint {
-        return VerticalPoint::create(
-            $this->height->subtract($geoidHeightCorrectionModelFile->getAdjustment($this)),
+            $this->height->subtract($geoidHeightCorrectionModelFile->getHeightAdjustment($this)),
             $to,
             $this->getCoordinateEpoch()
         );
@@ -2312,74 +2220,33 @@ public function geographic3DToGravityHeightIGNF(
 
     /**
      * NADCON5.
-     * Geodetic transformation operating on geographic coordinate differences by bi-quadratic interpolation.  Input
-     * expects longitudes to be positive east in range 0-360° (0° = Greenwich).
+     * @internal just a wrapper
      */
-    public function NADCON5(
+    public function offsetsFromGridNADCON5(
         Geographic $to,
         NADCON5Grid $latitudeDifferenceFile,
         NADCON5Grid $longitudeDifferenceFile,
         ?NADCON5Grid $ellipsoidalHeightDifferenceFile,
         bool $inReverse
     ): self {
-        /*
-         * Ideally most of this logic (especially reverse case) would be in the NADCON5Grid class like the other grids,
-         * but NADCON5 uses different files for latitude/longitude/height that need to be combined at runtime so that
-         * isn't possible.
-         */
-        if (!$inReverse) {
-            $latitudeAdjustment = new ArcSecond($latitudeDifferenceFile->getForwardAdjustment($this));
-            $longitudeAdjustment = new ArcSecond($longitudeDifferenceFile->getForwardAdjustment($this));
-            $heightAdjustment = $this->getHeight() && $ellipsoidalHeightDifferenceFile ? new Metre($ellipsoidalHeightDifferenceFile->getForwardAdjustment($this)) : null;
-
-            return self::create($this->latitude->add($latitudeAdjustment), $this->longitude->add($longitudeAdjustment), $heightAdjustment ? $this->height->add($heightAdjustment) : null, $to, $this->getCoordinateEpoch());
-        }
-
-        $iteration = $this;
-
-        do {
-            $prevIteration = $iteration;
-            $latitudeAdjustment = new ArcSecond($latitudeDifferenceFile->getForwardAdjustment($iteration));
-            $longitudeAdjustment = new ArcSecond($longitudeDifferenceFile->getForwardAdjustment($iteration));
-            $heightAdjustment = $this->getHeight() && $ellipsoidalHeightDifferenceFile ? new Metre($ellipsoidalHeightDifferenceFile->getForwardAdjustment($iteration)) : null;
-            $iteration = self::create($this->latitude->subtract($latitudeAdjustment), $this->longitude->subtract($longitudeAdjustment), $heightAdjustment ? $this->height->subtract($heightAdjustment) : null, $to, $this->getCoordinateEpoch());
-        } while (abs($iteration->latitude->subtract($prevIteration->latitude)->getValue()) > self::ITERATION_CONVERGENCE_GRID && abs($iteration->longitude->subtract($prevIteration->longitude)->getValue()) > self::ITERATION_CONVERGENCE_GRID && ($this->height === null || abs($iteration->height->subtract($prevIteration->height)->getValue()) > self::ITERATION_CONVERGENCE_GRID));
-
-        return $iteration;
-    }
-
-    /**
-     * NTv2
-     * Geodetic transformation operating on geographic coordinate differences by bi-linear interpolation.  Supersedes
-     * NTv1 (transformation method code 9614).  Input expects longitudes to be positive west.
-     */
-    public function NTv2(
-        Geographic $to,
-        NTv2Grid $latitudeAndLongitudeDifferenceFile,
-        bool $inReverse
-    ): self {
-        if (!$inReverse) {
-            return $latitudeAndLongitudeDifferenceFile->applyForwardAdjustment($this, $to);
-        }
+        $aggregation = new NADCON5Grids($longitudeDifferenceFile, $latitudeDifferenceFile, $ellipsoidalHeightDifferenceFile);
 
-        return $latitudeAndLongitudeDifferenceFile->applyReverseAdjustment($this, $to);
+        return $this->offsetsFromGrid($to, $aggregation, $inReverse);
     }
 
     /**
-     * Geocentric translation by Grid Interpolation (IGN France).
+     * Geographic offsets from grid.
      */
-    public function geocentricTranslationByGridInterpolationIGNF(
+    public function offsetsFromGrid(
         Geographic $to,
-        IGNFGeocentricTranslationGrid $geocentricTranslationFile,
-        string $EPSGCodeForInterpolationCRS,
-        string $EPSGCodeForStandardCT,
+        GeographicGrid $offsetsFile,
         bool $inReverse
     ): self {
         if (!$inReverse) {
-            return $geocentricTranslationFile->applyForwardAdjustment($this, $to);
+            return $offsetsFile->applyForwardAdjustment($this, $to);
         }
 
-        return $geocentricTranslationFile->applyReverseAdjustment($this, $to);
+        return $offsetsFile->applyReverseAdjustment($this, $to);
     }
 
     public function asGeographicValue(): GeographicValue
diff --git a/src/VerticalPoint.php b/src/VerticalPoint.php
index e24305734..3872f1e3d 100644
--- a/src/VerticalPoint.php
+++ b/src/VerticalPoint.php
@@ -13,7 +13,7 @@
 use DateTime;
 use DateTimeImmutable;
 use DateTimeInterface;
-use PHPCoord\CoordinateOperation\GTXGrid;
+use PHPCoord\CoordinateOperation\GeographicGeoidHeightGrid;
 use PHPCoord\CoordinateReferenceSystem\Vertical;
 use PHPCoord\Exception\InvalidCoordinateReferenceSystemException;
 use PHPCoord\UnitOfMeasure\Angle\Angle;
@@ -101,7 +101,7 @@ public function __toString(): string
      * This transformation allows calculation of height (or depth) in the target system by adding the parameter value
      * to the height (or depth)-value of the point in the source system.
      */
-    public function verticalOffset(
+    public function offset(
         Vertical $to,
         Length $verticalOffset
     ): self {
@@ -113,7 +113,7 @@ public function verticalOffset(
      * This transformation allows calculation of height in the target system by applying the parameter values to the
      * height value of the point in the source system.
      */
-    public function verticalOffsetAndSlope(
+    public function offsetAndSlope(
         Vertical $to,
         Angle $ordinate1OfEvaluationPoint,
         Angle $ordinate2OfEvaluationPoint,
@@ -181,21 +181,20 @@ public function zeroTideHeightToMeanTideHeightEVRF2019(
     }
 
     /**
-     * Vertical Offset by Grid Interpolation (gtx).
+     * Vertical Offset by Grid Interpolation.
      */
-    public function verticalOffsetGTX(
+    public function offsetFromGrid(
         Vertical $to,
-        GTXGrid $verticalOffsetFile,
-        string $EPSGCodeForInterpolationCRS,
+        GeographicGeoidHeightGrid $offsetsFile,
         bool $inReverse,
         GeographicPoint $horizontalPoint
     ): self {
-        $delta = $verticalOffsetFile->getAdjustment($horizontalPoint);
+        $offset = $offsetsFile->getHeightAdjustment($horizontalPoint);
 
         if ($inReverse) {
-            $delta = $delta->multiply(-1);
+            $offset = $offset->multiply(-1);
         }
 
-        return static::create($this->height->add($delta), $to);
+        return static::create($this->height->add($offset), $to);
     }
 }
diff --git a/tests/CompoundPointTest.php b/tests/CompoundPointTest.php
index da8e251a1..265319032 100644
--- a/tests/CompoundPointTest.php
+++ b/tests/CompoundPointTest.php
@@ -8,7 +8,6 @@
 
 namespace PHPCoord;
 
-use PHPCoord\CoordinateOperation\IGNESHeightETRS89REDNAPSpainProvider;
 use function class_exists;
 use DateTime;
 use DateTimeImmutable;
@@ -16,6 +15,7 @@
 use PHPCoord\CoordinateOperation\CoordinateOperations;
 use PHPCoord\CoordinateOperation\CRSTransformations;
 use PHPCoord\CoordinateOperation\GTXNZGeoid2016Provider;
+use PHPCoord\CoordinateOperation\IGNESHeightETRS89REDNAPSpainProvider;
 use PHPCoord\CoordinateOperation\IGNFHeightRGF93v2bNGFIGN69FranceProvider;
 use PHPCoord\CoordinateOperation\OSTN15OSGM15Provider;
 use PHPCoord\CoordinateReferenceSystem\Compound;
@@ -159,7 +159,7 @@ public function testGeographic3DTo2DPlusGravityHeightGTX(): void
             Compound::fromSRID(Compound::EPSG_NZGD2000_PLUS_NZVD2016_HEIGHT)
         );
         $toCRS = Geographic3D::fromSRID(Geographic3D::EPSG_NZGD2000);
-        $to = $from->geographic3DTo2DPlusGravityHeightGTX($toCRS, (new GTXNZGeoid2016Provider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new GTXNZGeoid2016Provider())->provideGrid());
 
         self::assertEqualsWithDelta(-36.9003, $to->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(174.7794, $to->getLongitude()->getValue(), 0.00000000001);
@@ -185,7 +185,7 @@ public function testGeographic3DTo2DPlusGravityHeightIGNF(): void
             Compound::fromSRID(Compound::EPSG_RGF93_V2B_PLUS_NGF_IGN69_HEIGHT)
         );
         $toCRS = Geographic3D::fromSRID(Geographic3D::EPSG_RGF93_V2B);
-        $to = $from->geographic3DTo2DPlusGravityHeightIGNF($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid());
 
         self::assertEqualsWithDelta(48.858222, $to->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(2.2945, $to->getLongitude()->getValue(), 0.00000000001);
@@ -211,7 +211,7 @@ public function testGeographic3DTo2DPlusGravityHeightIGNESSpain(): void
             Compound::fromSRID(Compound::EPSG_ETRS89_PLUS_ALICANTE_HEIGHT)
         );
         $toCRS = Geographic3D::fromSRID(Geographic3D::EPSG_ETRS89);
-        $to = $from->geographic3DTo2DPlusGravityHeightIGNES($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid());
 
         self::assertEqualsWithDelta(41.403611, $to->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(2.174444, $to->getLongitude()->getValue(), 0.00000000001);
diff --git a/tests/GeographicPoint3DTest.php b/tests/GeographicPoint3DTest.php
index c10aeda01..4368776d7 100644
--- a/tests/GeographicPoint3DTest.php
+++ b/tests/GeographicPoint3DTest.php
@@ -68,7 +68,7 @@ public function testGeographic3DTo2DPlusGravityHeightGTXNZ(): void
         }
         $from = GeographicPoint::create(new Degree(-36.9003), new Degree(174.7794), new Metre(50), Geographic3D::fromSRID(Geographic3D::EPSG_NZGD2000));
         $toCRS = Compound::fromSRID(Compound::EPSG_NZGD2000_PLUS_NZVD2016_HEIGHT);
-        $to = $from->geographic3DTo2DPlusGravityHeightGTX($toCRS, (new GTXNZGeoid2016Provider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new GTXNZGeoid2016Provider())->provideGrid());
 
         self::assertEqualsWithDelta(-36.9003, $to->getHorizontalPoint()->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(174.7794, $to->getHorizontalPoint()->getLongitude()->getValue(), 0.00000000001);
@@ -82,7 +82,7 @@ public function testGeographic3DGravityHeightGTXNZ(): void
         }
         $from = GeographicPoint::create(new Degree(-36.9003), new Degree(174.7794), new Metre(50), Geographic3D::fromSRID(Geographic3D::EPSG_NZGD2000));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_NZVD2016_HEIGHT);
-        $to = $from->geographic3DToGravityHeightGTX($toCRS, (new GTXNZGeoid2016Provider())->provideGrid());
+        $to = $from->geographic3DToGravityHeightFromGrid($toCRS, (new GTXNZGeoid2016Provider())->provideGrid());
 
         self::assertEqualsWithDelta(15.715, $to->getHeight()->getValue(), 0.0001);
     }
@@ -94,7 +94,7 @@ public function testGeographic3DTo2DPlusGravityHeightGTXAustralia(): void
         }
         $from = GeographicPoint::create(new Degree(-36.9003), new Degree(144.7794), new Metre(50), Geographic3D::fromSRID(Geographic3D::EPSG_GDA2020));
         $toCRS = Compound::fromSRID(Compound::EPSG_GDA2020_PLUS_AHD_HEIGHT);
-        $to = $from->geographic3DTo2DPlusGravityHeightGTX($toCRS, (new GTXGDA2020AHDProvider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new GTXGDA2020AHDProvider())->provideGrid());
 
         self::assertEqualsWithDelta(-36.9003, $to->getHorizontalPoint()->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(144.7794, $to->getHorizontalPoint()->getLongitude()->getValue(), 0.00000000001);
@@ -108,7 +108,7 @@ public function testGeographic3DTo2DPlusGravityHeightIGNFFrance(): void
         }
         $from = GeographicPoint::create(new Degree(48.858222), new Degree(2.2945), new Metre(50), Geographic3D::fromSRID(Geographic3D::EPSG_RGF93_V2B));
         $toCRS = Compound::fromSRID(Compound::EPSG_RGF93_V2B_PLUS_NGF_IGN69_HEIGHT);
-        $to = $from->geographic3DTo2DPlusGravityHeightIGNF($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid());
 
         self::assertEqualsWithDelta(48.858222, $to->getHorizontalPoint()->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(2.2945, $to->getHorizontalPoint()->getLongitude()->getValue(), 0.00000000001);
@@ -117,12 +117,12 @@ public function testGeographic3DTo2DPlusGravityHeightIGNFFrance(): void
 
     public function testGeographic3DGravityHeightIGNFFrance(): void
     {
-        if (!class_exists(GTXNZGeoid2016Provider::class)) {
+        if (!class_exists(IGNFHeightRGF93v2bNGFIGN69FranceProvider::class)) {
             self::markTestSkipped('Requires phpcoord/datapack-europe');
         }
         $from = GeographicPoint::create(new Degree(48.858222), new Degree(2.2945), new Metre(50), Geographic3D::fromSRID(Geographic3D::EPSG_RGF93_V2B));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_NGF_IGN69_HEIGHT);
-        $to = $from->geographic3DToGravityHeightIGNF($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid());
+        $to = $from->geographic3DToGravityHeightFromGrid($toCRS, (new IGNFHeightRGF93v2bNGFIGN69FranceProvider())->provideGrid());
 
         self::assertEqualsWithDelta(6.187, $to->getHeight()->getValue(), 0.001);
     }
@@ -134,7 +134,7 @@ public function testGeographic3DTo2DPlusGravityHeightIGNESSpain(): void
         }
         $from = GeographicPoint::create(new Degree(41.403611), new Degree(2.174444), new Metre(0), Geographic3D::fromSRID(Geographic3D::EPSG_ETRS89));
         $toCRS = Compound::fromSRID(Compound::EPSG_ETRS89_PLUS_ALICANTE_HEIGHT);
-        $to = $from->geographic3DTo2DPlusGravityHeightIGNES($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid(), '');
+        $to = $from->geographic3DTo2DPlusGravityHeightFromGrid($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid());
 
         self::assertEqualsWithDelta(41.403611, $to->getHorizontalPoint()->getLatitude()->getValue(), 0.00000000001);
         self::assertEqualsWithDelta(2.174444, $to->getHorizontalPoint()->getLongitude()->getValue(), 0.00000000001);
@@ -148,7 +148,7 @@ public function testGeographic3DGravityHeightIGNESSpain(): void
         }
         $from = GeographicPoint::create(new Degree(41.403611), new Degree(2.174444), new Metre(0), Geographic3D::fromSRID(Geographic3D::EPSG_ETRS89));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_ALICANTE_HEIGHT);
-        $to = $from->geographic3DToGravityHeightIGNES($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid());
+        $to = $from->geographic3DToGravityHeightFromGrid($toCRS, (new IGNESHeightETRS89REDNAPSpainProvider())->provideGrid());
 
         self::assertEqualsWithDelta(-49.196, $to->getHeight()->getValue(), 0.001);
     }
diff --git a/tests/GeographicPointTest.php b/tests/GeographicPointTest.php
index 02ccb0ab3..7bc995b9c 100644
--- a/tests/GeographicPointTest.php
+++ b/tests/GeographicPointTest.php
@@ -1051,7 +1051,7 @@ public function testNADCON5Forward3DTransform3DPoint(): void
         }
         $from = GeographicPoint::create(new Degree(43.7737469611), new Degree(-99.3189543667), new Metre(100), Geographic3D::fromSRID(Geographic3D::EPSG_NAD83_FBN));
         $toCRS = Geographic3D::fromSRID(Geographic3D::EPSG_NAD83_NSRS2007);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD83FBNNAD832007CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD83FBNNAD832007CONUSLongitudeProvider())->provideGrid(),
@@ -1071,7 +1071,7 @@ public function testNADCON5Reverse3DTransform3DPoint(): void
         }
         $from = GeographicPoint::create(new Degree(43.7737471044), new Degree(-99.3189544237), new Metre(100.005), Geographic3D::fromSRID(Geographic3D::EPSG_NAD83_FBN));
         $toCRS = Geographic3D::fromSRID(Geographic3D::EPSG_NAD83_NSRS2007);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD83FBNNAD832007CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD83FBNNAD832007CONUSLongitudeProvider())->provideGrid(),
@@ -1091,7 +1091,7 @@ public function testNADCON5Forward3DTransform2DPoint(): void
         }
         $from = GeographicPoint::create(new Degree(43.7737469611), new Degree(-99.3189543667), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD83_FBN));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD83_NSRS2007);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD83FBNNAD832007CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD83FBNNAD832007CONUSLongitudeProvider())->provideGrid(),
@@ -1111,7 +1111,7 @@ public function testNADCON5Reverse3DTransform2DPoint(): void
         }
         $from = GeographicPoint::create(new Degree(43.7737471044), new Degree(-99.3189544237), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD83_FBN));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD83_NSRS2007);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD83FBNNAD832007CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD83FBNNAD832007CONUSLongitudeProvider())->provideGrid(),
@@ -1131,7 +1131,7 @@ public function testNADCON5Forward2D(): void
         }
         $from = GeographicPoint::create(new Degree(40.689247), new Degree(-74.044502), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD27));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD83);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD27NAD831986CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD27NAD831986CONUSLongitudeProvider())->provideGrid(),
@@ -1151,7 +1151,7 @@ public function testNADCON5Reverse2D(): void
         }
         $from = GeographicPoint::create(new Degree(40.6893492339), new Degree(-74.0440875374), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD27));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD83);
-        $to = $from->NADCON5(
+        $to = $from->offsetsFromGridNADCON5(
             $toCRS,
             (new NADCON5NAD27NAD831986CONUSLatitudeProvider())->provideGrid(),
             (new NADCON5NAD27NAD831986CONUSLongitudeProvider())->provideGrid(),
@@ -1171,7 +1171,7 @@ public function testNTv2ForwardCanada(): void
         }
         $from = GeographicPoint::create(new Degree(50.8713458), new Degree(-114.2934808), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD27));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD83);
-        $to = $from->NTv2(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new NTv2NAD27NAD83CanadaProvider())->provideGrid(),
             false
@@ -1189,7 +1189,7 @@ public function testNTv2ReverseCanada(): void
         }
         $from = GeographicPoint::create(new Degree(50.871401224), new Degree(-114.294481160), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD83));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NAD27);
-        $to = $from->NTv2(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new NTv2NAD27NAD83CanadaProvider())->provideGrid(),
             true
@@ -1207,7 +1207,7 @@ public function testNTv2ForwardAustralia(): void
         }
         $from = GeographicPoint::create(new Degree(-29.05000000), new Degree(120.84722222), null, Geographic2D::fromSRID(Geographic2D::EPSG_AGD66));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_GDA94);
-        $to = $from->NTv2(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new NTv2AGD66GDA94AustraliaProvider())->provideGrid(),
             false
@@ -1225,7 +1225,7 @@ public function testNTv2ReverseAustralia(): void
         }
         $from = GeographicPoint::create(new Degree(-29.04869025), new Degree(120.84864381), null, Geographic2D::fromSRID(Geographic2D::EPSG_AGD66));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_GDA94);
-        $to = $from->NTv2(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new NTv2AGD66GDA94AustraliaProvider())->provideGrid(),
             true
@@ -1243,11 +1243,9 @@ public function testIGNFGeocentricTranslationFranceForward(): void
         }
         $from = GeographicPoint::create(new Degree(48.84451225), new Degree(2.42567186), null, Geographic2D::fromSRID(Geographic2D::EPSG_NTF));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_RGF93_V1);
-        $to = $from->geocentricTranslationByGridInterpolationIGNF(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new IGNFGeocentricTranslationNTFRGF93Provider())->provideGrid(),
-            '',
-            '',
             false
         );
 
@@ -1263,11 +1261,9 @@ public function testIGNFGeocentricTranslationFranceReverse(): void
         }
         $from = GeographicPoint::create(new Degree(48.844445839), new Degree(2.424971108), null, Geographic2D::fromSRID(Geographic2D::EPSG_RGF93_V1));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NTF);
-        $to = $from->geocentricTranslationByGridInterpolationIGNF(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new IGNFGeocentricTranslationNTFRGF93Provider())->provideGrid(),
-            '',
-            '',
             true
         );
 
@@ -1283,11 +1279,9 @@ public function testIGNFGeocentricTranslationNoumeaForward(): void
         }
         $from = GeographicPoint::create(new Degree(-22.268889), new Degree(166.419444), null, Geographic2D::fromSRID(Geographic2D::EPSG_NEA74_NOUMEA));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_RGNC91_93);
-        $to = $from->geocentricTranslationByGridInterpolationIGNF(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new IGNFGeocentricTranslationNEA74NoumeaRGNC9193Provider())->provideGrid(),
-            '',
-            '',
             false
         );
 
@@ -1303,11 +1297,9 @@ public function testIGNFGeocentricTranslationNoumeaReverse(): void
         }
         $from = GeographicPoint::create(new Degree(-22.26612898), new Degree(166.42277652), null, Geographic2D::fromSRID(Geographic2D::EPSG_RGNC91_93));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_NEA74_NOUMEA);
-        $to = $from->geocentricTranslationByGridInterpolationIGNF(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new IGNFGeocentricTranslationNEA74NoumeaRGNC9193Provider())->provideGrid(),
-            '',
-            '',
             true
         );
 
@@ -1323,11 +1315,9 @@ public function testIGNFGeocentricTranslationGrandeTerreForward(): void
         }
         $from = GeographicPoint::create(new Degree(-22.268889), new Degree(166.419444), null, Geographic2D::fromSRID(Geographic2D::EPSG_IGN72_GRANDE_TERRE));
         $toCRS = Geographic2D::fromSRID(Geographic2D::EPSG_RGNC91_93);
-        $to = $from->geocentricTranslationByGridInterpolationIGNF(
+        $to = $from->offsetsFromGrid(
             $toCRS,
             (new IGNFGeocentricTranslationIGN72GrandeTerreRGNC9193Provider())->provideGrid(),
-            '',
-            '',
             false
         );
 
diff --git a/tests/VerticalPointTest.php b/tests/VerticalPointTest.php
index 40f2e5246..d09eb3fca 100644
--- a/tests/VerticalPointTest.php
+++ b/tests/VerticalPointTest.php
@@ -75,7 +75,7 @@ public function testVerticalOffset(): void
     {
         $from = VerticalPoint::create(new Metre(2.55), Vertical::fromSRID(Vertical::EPSG_BALTIC_1977_HEIGHT));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_BLACK_SEA_HEIGHT);
-        $to = $from->verticalOffset($toCRS, new Metre(0.4));
+        $to = $from->offset($toCRS, new Metre(0.4));
 
         self::assertEqualsWithDelta(2.95, $to->getHeight()->getValue(), 0.001);
     }
@@ -85,7 +85,7 @@ public function testVerticalOffsetAndSlope(): void
         $horizontalPoint = GeographicPoint::create(new Radian(0.826122513), new Radian(0.168715161), null, Geographic2D::fromSRID(Geographic2D::EPSG_ETRS89));
         $from = VerticalPoint::create(new Metre(473), Vertical::fromSRID(Vertical::EPSG_LN02_HEIGHT));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_EVRF2000_HEIGHT);
-        $to = $from->verticalOffsetAndSlope($toCRS, new Radian(0.818850307), new Radian(0.142826110), new Metre(-0.245), new Radian(-0.000001018), new Radian(-0.000000155), 'urn:ogc:def:crs:EPSG::4258', $horizontalPoint);
+        $to = $from->offsetAndSlope($toCRS, new Radian(0.818850307), new Radian(0.142826110), new Metre(-0.245), new Radian(-0.000001018), new Radian(-0.000000155), 'urn:ogc:def:crs:EPSG::4258', $horizontalPoint);
 
         self::assertEqualsWithDelta(472.69, $to->getHeight()->asMetres()->getValue(), 0.001);
     }
@@ -136,7 +136,7 @@ public function testVerticalOffsetGTXForward(): void
         $horizontalPoint = GeographicPoint::create(new Degree(-44.42), new Degree(168.92), null, Geographic2D::fromSRID(Geographic2D::EPSG_NZGD2000));
         $from = VerticalPoint::create(new Metre(50), Vertical::fromSRID(Vertical::EPSG_NZVD2016_HEIGHT));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_DUNEDIN_1958_HEIGHT);
-        $to = $from->verticalOffsetGTX($toCRS, (new GTXDunedin1958NZVD2016Provider())->provideGrid(), '', false, $horizontalPoint);
+        $to = $from->offsetFromGrid($toCRS, (new GTXDunedin1958NZVD2016Provider())->provideGrid(), false, $horizontalPoint);
 
         self::assertEqualsWithDelta(50.304, $to->getHeight()->getValue(), 0.001);
     }
@@ -149,7 +149,7 @@ public function testVerticalOffsetGTXReverse(): void
         $horizontalPoint = GeographicPoint::create(new Degree(-44.42), new Degree(168.92), null, Geographic2D::fromSRID(Geographic2D::EPSG_NZGD2000));
         $from = VerticalPoint::create(new Metre(50.304), Vertical::fromSRID(Vertical::EPSG_DUNEDIN_1958_HEIGHT));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_NZVD2016_HEIGHT);
-        $to = $from->verticalOffsetGTX($toCRS, (new GTXDunedin1958NZVD2016Provider())->provideGrid(), '', true, $horizontalPoint);
+        $to = $from->offsetFromGrid($toCRS, (new GTXDunedin1958NZVD2016Provider())->provideGrid(), true, $horizontalPoint);
 
         self::assertEqualsWithDelta(50.000, $to->getHeight()->getValue(), 0.001);
     }
@@ -162,7 +162,7 @@ public function testVerticalOffsetGTXUSVERTCON(): void
         $horizontalPoint = GeographicPoint::create(new Degree(29.4667897), new Degree(-98.4803739), null, Geographic2D::fromSRID(Geographic2D::EPSG_NAD83));
         $from = VerticalPoint::create(new Metre(247.47), Vertical::fromSRID(Vertical::EPSG_NGVD29_HEIGHT_M));
         $toCRS = Vertical::fromSRID(Vertical::EPSG_NAVD88_HEIGHT);
-        $to = $from->verticalOffsetGTX($toCRS, (new GTXNGVD29NAVD88CONUSCentralProvider())->provideGrid(), '', false, $horizontalPoint);
+        $to = $from->offsetFromGrid($toCRS, (new GTXNGVD29NAVD88CONUSCentralProvider())->provideGrid(), false, $horizontalPoint);
 
         self::assertEqualsWithDelta(247.599, $to->getHeight()->getValue(), 0.001);
     }