KML file read via `vect()` on Windows loads only 2 attributes (vs ~26 on Linux) — likely due to missing LIBKML driver

[YONGHUNI]

Description:

Summary

When reading the same KML file using terra::vect() on Windows, only 2 attributes are loaded. On the same file in Ubuntu, the full ~26 attributes load correctly. The difference appears tied to the presence of the LIBKML driver in the GDAL build on Linux, which is absent on the Windows build.

Environment

Ubuntu

• terra::gdal() → “3.8.4”
• terra::gdal(drivers=TRUE) shows LIBKML among vector drivers

Windows

• terra::gdal() → “3.11.0”
• terra::gdal(drivers=TRUE) shows only KML and KMLSUPEROVERLAY, no LIBKML

Reproducible example

library(terra)
fn <- "https://gitlab.mpcdf.mpg.de/yhsuh/RefugeeCamp/-/raw/main/Accessibility/data/camp_outline/20230412_a1_camp_outlines.kml"
v <- vect(fn)
print(v)
terra::gdal(drivers=TRUE) |> subset(grepl("KML|kml", name))

• On Ubuntu the output shows dimensions : 33, 26 (geometries, attributes)

> terra::vect("https://gitlab.mpcdf.mpg.de/yhsuh/RefugeeCamp/-/raw/main/Accessibility/data/camp_outline/20230412_a1_camp_outlines.kml")
 class       : SpatVector 
 geometry    : polygons 
 dimensions  : 33, 26  (geometries, attributes)
 extent      : 92.12973, 92.26863, 20.91856, 21.22292  (xmin, xmax, ymin, ymax)
 source      : 20230412_a1_camp_outlines.kml (20230412_A1_Camp_Outlines)
 coord. ref. : lon/lat WGS 84 (EPSG:4326) 
 names       :  Name description timestamp    begin      end altitudeMode tessellate extrude visibility drawOrder (and 16 more)
 type        : <chr>       <chr>  <POSIXt> <POSIXt> <POSIXt>        <chr>      <int>   <int>      <int>     <int>              
 values      :    NA          NA      <NA>     <NA>     <NA>           NA         -1       0         -1        NA              
                  NA          NA      <NA>     <NA>     <NA>           NA         -1       0         -1        NA              
                  NA          NA      <NA>     <NA>     <NA>           NA         -1       0         -1        NA              
> terra::gdal()
[1] "3.8.4"
> subset(terra::gdal(drivers=TRUE), grepl("KML|kml", name))
               name raster vector        can  vsi                        long.name
103             KML  FALSE   TRUE read/write TRUE    Keyhole Markup Language (KML)
104 KMLSUPEROVERLAY   TRUE  FALSE read/write TRUE                Kml Super Overlay
110          LIBKML  FALSE   TRUE read/write TRUE Keyhole Markup Language (LIBKML)

• On Windows it shows dimensions : 33, 2 (geometries, attributes)

> terra::vect("https://gitlab.mpcdf.mpg.de/yhsuh/RefugeeCamp/-/raw/main/Accessibility/data/camp_outline/20230412_a1_camp_outlines.kml")
 class       : SpatVector 
 geometry    : polygons 
 dimensions  : 33, 2  (geometries, attributes)
 extent      : 92.12973, 92.26863, 20.91856, 21.22292  (xmin, xmax, ymin, ymax)
 source      : 20230412_a1_camp_outlines.kml (20230412_A1_Camp_Outlines)
 coord. ref. : lon/lat WGS 84 (EPSG:4326) 
 names       :  Name Description
 type        : <chr>       <chr>
 values      :                  
                                
                                
> terra::gdal()
[1] "3.11.0"
> subset(terra::gdal(drivers=TRUE), grepl("KML|kml", name))
              name raster vector        can  vsi                     long.name
94             KML  FALSE   TRUE read/write TRUE Keyhole Markup Language (KML)
95 KMLSUPEROVERLAY   TRUE  FALSE read/write TRUE             Kml Super Overlay

Hypothesis

The GDAL build on Windows uses only the KML OGR driver, which may not fully support nested folder structures, extended attributes or style/detail tags in KML. The build on Ubuntu includes the LIBKML driver, which supports a fuller KML spec and thus loads more attributes. According to GDAL documentation: “If you build and include this LIBKML driver, it will become the default reader of KML for OGR.”

Request / Questions

• Could the Windows binaries of terra (or its GDAL dependency) include a version built with LIBKML, or provide guidance for users to install one?

Additional details

• KML file: polygon layer (33 geometries) with ~26 attribute fields.
• On Windows: names(v) yields only "Name", "Description" (2 fields).
• On Ubuntu: names(v) yields all ~26 fields.
• Similar issues have been observed via the sf package: driver difference (KML vs LIBKML) leads to attribute loss on some platforms.
• Providing an optional diagnostic: terra::gdal(drivers=TRUE) and verifying driver list.

Session Info

• Ubuntu

> sessionInfo()
R version 4.5.0 (2025-04-11)
Platform: x86_64-pc-linux-gnu
Running under: Ubuntu 24.04.3 LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 
LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.26.so;  LAPACK version 3.12.0

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8   
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

time zone: Etc/UTC
tzcode source: system (glibc)

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base     

other attached packages:
[1] terra_1.8-54

loaded via a namespace (and not attached):
[1] compiler_4.5.0    tools_4.5.0       rstudioapi_0.17.1 yaml_2.3.10       Rcpp_1.0.14       codetools_0.2-20  renv_1.1.4  

• Windows

> sessionInfo()
R version 4.5.0 (2025-04-11 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 26100)

Matrix products: default
  LAPACK version 3.12.1

locale:
[1] LC_COLLATE=English_United States.utf8  LC_CTYPE=English_United States.utf8    LC_MONETARY=English_United States.utf8
[4] LC_NUMERIC=C                           LC_TIME=English_United States.utf8    

time zone: Europe/Berlin
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] terra_1.8-54

loaded via a namespace (and not attached):
[1] compiler_4.5.0    tools_4.5.0       rstudioapi_0.17.1 Rcpp_1.0.14       codetools_0.2-20 

Thank you for your attention.

[rhijmans]

What is included in the windows binaries depends on what is included in RTools. If there is something important missing I would ask for it to be included, but I am not sure if this applies here. A work around would be to read the kml directly and extract the needed information. If such a function is available I could include it in terra.