Disallow custom CRS / SRID?

[AntoineAugusti]

Hi,

We've seen people producing GeoJSONs with a crs field and specifying something different than WGS84 which is not compliant with the specification.

I'm wondering if you considered:

• making sure that people do not specify another projection system
• specify integer constraints for coordinates

Example GeoJSON

This GeoJSON specifies a custom crs and doesn't use WGS84 for coordinates.

{
   "type":"FeatureCollection",
   "name":"amg_cyclable_MRN_08_03_2022",
   "crs":{
      "type":"name",
      "properties":{
         "name":"urn:ogc:def:crs:EPSG::3949"
      }
   },
   "features":[
      {
         "type":"Feature",
         "properties":{
            "id_local":"1",
            "id_osm":"285915734",
            "num_iti":"0",
            "date_maj":"2021-12-20",
            "source":"OSM",
            "project_c":"CC49",
            "long_m":36.525,
            "code_com_d":"76231",
            "code_com_g":"76231",
            "reseau_loc":"Autre",
            "local_d":"CHAUSSEE",
            "statut_d":"EN SERVICE",
            "regime_d":"ZONE DE RENCONTRE",
            "sens_d":"UNIDIRECTIONNEL",
            "ame_d":"AMENAGEMENT MIXTE PIETON VELO HORS VOIE VERTE",
            "ame_g":"AUCUN"
         },
         "geometry":{
            "type":"MultiLineString",
            "coordinates":[
               [
                  [
                     1552538.648,
                     8234688.966
                  ],
                  [
                     1552514.736,
                     8234694.519000000320375
                  ],
                  [
                     1552502.897000000113621,
                     8234692.723000000230968
                  ]
               ]
            ]
         }
      }
   ]
}