[PROJ] Issue with global GeoJSON in EPSG:3978

[Even Rouault]

Louis-Philippe,

The issue is that points at lat=-90 projected to EPSG:3978 go to infinity, which causes the 
reprojection issue of the whole world

You might want to add to your ogr2ogr commandline a clipping of the source to the 
northerm hemisphere, before reprojecting with:

-clipsrc -180 0 180 90


-clipsrc -180 -89.999 180 90  would also work. You really want to avoid -90


Even

> I  haven't digged very deep into this but I can identify at least two things
> that seem problematic to me.
> 
> EPSG:3978 is only defined in Canada. It is based on NAD83, so expecting a
> global dataset to be transformed to that CRS is asking a bit much.
> > The OSM base map is reprojected corretly, but the GeoJSON is simply not
> > displayed
> Is it though? I see two occurrences of India and as far as I am aware only
> one exist in real life.
> 
> I would try to find a CRS that is better suited for your particular use
> case.
> 
> /Kristian
> 
> From: PROJ <proj-bounces at lists.osgeo.org> On Behalf Of Rousseau Lambert2,
> Louis-Philippe (EC) Sent: 18. august 2020 13:42
> To: proj at lists.osgeo.org
> Subject: [PROJ] Issue with global GeoJSON in EPSG:3978
> 
> 
> Hi,
> 
> I have a problem with reprojecting a global GeoJSON file with a hole over
> Canada from EPSG:4326 to EPSG:3978 (Canada Atlas Lambert).
> 
> You can see my GeoJSON below in this email. The global extent is x=-180,180
> and y=-90,90
> 
> I tried using:
> 
>   *   MapServer (7.4.4)
> 
>      *   I tried to serve the layer as WMS and display it in QGIS
>      *   Result: I expected the GeoJSON to be automatically cut to the
> EPSG:3978 extent and show the hole over Canada, but instead, the hole was
> displayed as the features on the map whitout the global extent.
> 
>   *   Opening raw GeoJSON directly in QGIS (3.15.0-Master, GDAL 3.2.0dev,
> PROJ 7.2.0)
> 
>      *   same results as MapServer in WMS
> 
>   *   ogr2ogr (GDAL 3.0.4)
> 
>      *   I tried to reproject the GeoJSON from EPSG:4326 to EPSG:3978
>      *   Result: the reprojection failed, my feature is empty
> 
>         *   ogr2ogr -f "GeoJSON" -s_srs EPSG:4326 -t_srs EPSG:3978
> 18-3978.geojson 17-4326.geojson ERROR 1: Full reprojection failed, but
> partial is possible if you define OGR_ENABLE_PARTIAL_REPROJECTION
> configuration option to TRUE ERROR 1: Failed to reproject feature 0
> (geometry probably out of source or destination SRS). ERROR 1: Terminating
> translation prematurely after failed
> translation of layer 17-4326 (use -skipfailures to skip errors)
> 
>   *   OpenLayers and the proj4 lib (proj4js/2.6.2/proj4.js)
> 
>      *   Here is an example reprojecting the GeoJSON to EPSG:3978:
> https://codepen.io/rousseaulambertlp/pen/wvGGBXd
> 
>         *   The OSM base map is reprojected corretly, but the GeoJSON is
> simply not displayed
> 
>      *   Here is the same code, but using a non global GeoJSON with a hole,
> which works: https://codepen.io/rousseaulambertlp/pen/YzqWVBZ *   But I see
> that a global WMS layer served from MapServer, works fine in this
> projection: https://codepen.io/rousseaulambertlp/pen/MWyeogM
> 
> My guess is these behaviors are caused by the proj library giving I have
> issues in all the examples above ?
> 
> So I wanted to know if this is expected behavior, giving I'm trying to
> display a global features on a projection with a smaller extent ? Or is
> this is bug (especially the inverted feature in QGIS) ?
> 
> Any idea of work around other then clipping the data to the EPSG:3978 extent
> ?
> 
> Thanks
> 
> LP
> 
> Here is the GeoJSON I used for example:
> 
> {
>   "type": "FeatureCollection",
>   "crs": {
>     "type": "name",
>     "properties": {
>       "name": "EPSG:4326"
>     }
>   },
>   "features": [
>     {
>      "type": "Feature",
>      "properties": {
>       "name": "test"
>       },
>       "geometry": {
>         "type": "Polygon",
>         "coordinates": [
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