[gdal-dev] Trouble reprojecting feature that crosses antimeridian

[Robin Wilson]

Thank you everyone for the responses, and Even for the bug fix.

Best regards,

Robin


On 29 March 2022 at 22:33:49, Even Rouault (even.rouault at spatialys.com) wrote:

Was a bug. Fix queued in https://github.com/OSGeo/gdal/pull/5543

Le 29/03/2022 à 22:30, Robin Wilson a écrit :
Hi,

I’ve been running into problems creating STAC items for images that cross the antimeridian. The geometries for the images are coming out as spanning the width of the whole world (from -180 to +180 degrees). With the help of the author of the tool I was using to create the STAC items (rio-stac), I’ve narrowed it down to a simple test case of reprojecting geometries (which is what the tool is doing internally).

If you put the following GeoJSON for an antimeridian-crossing polygon in WGS 84 / UTM zone 1N in a file called test_32601.geojson:

```
{"type":"Polygon","coordinates":[[[377120,7577600],[418080,7577600],[418080,7618560],[377120,7618560],[377120,7577600]]]}
```

and then run the following:

```
ogr2ogr -f GeoJSON -s_srs epsg:32601 -t_srs epsg:4326 out_4326.geojson test_32601.geojson
```

The contents of the output file will be:

```
{ "type": "Polygon", "coordinates": [ [ [ -179.018099960087909, 68.666857319910392 ], [ -178.985579869598382, 68.299719485120988 ], [ -179.976982644969041, 68.284942315413858 ], [ 179.974309855567753, 68.651801088224246 ], [ 180.0, 68.652259945574556 ], [ 180.0, 68.652259945541758 ], [ 180.0, 68.652259944541754 ], [ -180.0, 68.652259944541754 ], [ -180.0, 68.652259945541758 ], [ -180.0, 68.652259945610126 ], [ -179.018099960087909, 68.666857319910392 ] ] ] }
```

In that output geometry there are longitudes of 180 and -180, so when plotted on a map it spans the whole width of the world.

The author of the rio-stac library did a PR to try and fix this problem (https://github.com/developmentseed/rio-stac/pull/30), but it doesn’t seem to have fixed it for this example, as the underlying GDAL code used by his library (through rasterio, I believe) is giving this result.

I find this result unexpected, but I have no knowledge of how GDAL deals with the antimeridian. Is this to be expected, or is this potentially a bug? If it isn’t a bug, is there any way around this?

Best regards,

Robin

Dr Robin Wilson
www.rtwilson.com




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