Image bounds are in geographic coordinate system

[mcvittal]

Hello!

I'm not sure what I'm doing wrong here, but I'm trying to generate tiles from a GeoTIFF, but it can't assess that a tile is within its bounds because in the tile_exists method within base.py, the bounds array contains geographic lat/lon coordinates instead of projected coordinates.

My basic code is as follows:

from rio_tiler.io import COGReader 

with COGReader("myraster_projected.tif") as img:
  img.tile(1, 1, 1)

Which throws the error

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/mnt/c/Users/Alex/WORK/coding/landsat-tiler/rio-tiler/rio_tiler/io/cogeo.py", line 264, in tile
    raise TileOutsideBounds(
rio_tiler.errors.TileOutsideBounds: Tile 1/1/1 is outside myraster_projected.tif bounds

I've tried re-projecting my raster to EPSG:3857 but the issue still prevails - I've added some print statements to get the bounds array contents and it still prints out that it is in a geographic coordinate system. Is there an additional step I should be doing?

[vincentsarago]

Hi @mcvittal thanks for opening the issue.

the error message says that the Mercator Tile x=1, y=1, z=1 bounds coordinates do no intersect with your raster bounds.

what is the output of

from rio_tiler.io import COGReader
import morecantile

tms = morecantile.tms.get("WebMercatorQuad")
print(tms.bounds(1, 1, 1)

with COGReader("myraster_projected.tif") as img:
    print(img.bounds)

[mcvittal]

Thanks for the quick reply!

This outputs

BoundingBox(left=-2.0078911277343066e-13, bottom=-85.05112877980652, right=179.9999999999992, top=2.0355549961366507e-13)

(2.125432099751016, 48.64001935810568, 2.147842404720507, 48.65631726102131)

[vincentsarago]

BoundingBox(left=-2.0078911277343066e-13, bottom=-85.05112877980652, right=179.9999999999992, top=2.0355549961366507e-13)

(2.125432099751016, 48.64001935810568, 2.147842404720507, 48.65631726102131)

☝️ shows that your raster doesn't intersect with tile 1-1-1 (latitude of your file is ~48 North, while grid max lat is ~0)

I'm going to close this issue because it's not bug, but please feel free to re-open if you feel the documentation should better explain that we cannot read tiles that are outside your raster bounds 🙏

[mcvittal]

I'm just a little bit confused here. The image is a small high-res image located in Paris, France (Hence the location of 2, 48) - this should be well within the bounds of the Web Mercator maximum and minimum bounds. I'm trying to serve this as a tiled webmap, and thought that this tool would be the best way to do something like this on the fly. Below is a screenshot of the image with a Google Maps basemap:

Obviously, at zoom level 1, it would be a pretty useless webmap tile as it is very small, but it should be able to generate something at least.

[vincentsarago]

@mcvittal you are right, rio-tiler can create tile from you file (but I wouldn't recommend using it for really low zoom level).
The error you are experiencing for tile 1-1-1 is absolutely expected, the tile x=1, y=1, z=1 DO NOT intersect with your file thus rio-tiler CANNOT read the corresponding data for the tile bounds ... because it doesn't exist.

if you try tile x=1, y=0, z=1. it should work (but it will be really memory intensive: see #348)