I'm using ogr2ogr to convert some OSM data for Greenland (not really important for the question), from a PostGIS database to a file containing GeoJSON.
The problem is that the GeoJSON gets written without the crs attribute, even though I'm reprojecting to a non-4326 coordinate system (3189 to be specific). See below how I do this.
The srid of data in geometry column in the database table is 4326. I use the t_srs "epsg:3189" option to transform the coordinates, and this seems to work, i.e. the coordinates are not Lat/Lon.
Command used:
ogr2ogr -f "GeoJSON" greenland_coast.geojson \ PG:"host=localhost user=xxx dbname=greenland_osm password=xxx" \ -sql "select linestring from ways" -t_srs "epsg:3189" Snippet of GeoJSON result:
Notice the missing crs attribute that should indicate that the coordinates are in EPSG:3189.
{ "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": { }, "geometry": { "type": "LineString", "coordinates": [ [ -548886.066167875193059, 9361706.390365654602647 ], ...] } }, ... ]} The coordinates seem to have been transformed correctly, but there is no crs field telling a reader of the GeoJSON file that the coordinates are in epsg:3189
The GeoJSON spec states:
If no crs member can be so acquired, the default CRS shall apply to the GeoJSON object ... The default CRS is a geographic coordinate reference system, using the WGS84 datum, and with longitude and latitude units of decimal degrees.
I assumed that since I'm reprojecting to a non-geographic coordinate system, a crs key-value pair would be written to the GeoJSON (indicating EPSG:3189 in my case).
My question
Which of the following statements is more true?
- I'm using ogr2ogr wrong
- My expectations of ogr2ogr are too high
- There an error in the GeoJSON driver
