Dear GDAL-devs,
while working on a small project, I (more or less inevitably) came
across the problem of what to do when a bounding box geometry, that is
to be translated to EPSG:4326, crosses the antimeridian in the target
SRS (i.e. EPSG:4326). The docs for the C function `OCTTransformBounds`
note that the user has to check if a) the destination/target SRS is
geographic (which it is in my case), b) if the first SRS axis is
latitude or longitude and c) depending on that check whether the maximum
longitudinal bounding coordinate is smaller then than the minimum
bounding longitudinal coordinate, accessing the correct axis.
Unfortunately, the above mentioned check whether the bounding box
"crossed the antimeridian" confuses me. Applying this check on the
output correctly detects crossing of the antimeridian in EPSG:4326.
While I may very well misunderstand the documentation and/or the
underlying processing, I would be thankful for an answer to the
following two questions:
1. Is the documentation correct that input data must be checked and not
the output data, i.e. `out_xmax` etc.?
2. If so, why should this check be done on the input coordinates even
though they may not be in a geographic coordinate reference system
in the first place or have a SRS assigned that handles 180°
crossings (e.g. Mollweide centered at 180°)?
Kind regards and thanks in advance,
Florian Katerndahl
_______________________________________________
gdal-dev mailing list
gdal-dev@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/gdal-dev
