Adding SRID option to Geojson parser

[mauritskorse]

It would be great if parsing geojson data of a certain SRID could be done more easily. It currently can't be directly done using the geojson parser. The parser has SRID 4326 hardcoded. Therefore we need to use ST::transform as second step. But then the actual geometry object doesn't have the correct SRID set. Also, many methods within the package accept an srid parameter and therefore you might expect the geojson parser should also allow for an SRID to be set.

Current situation

  $parser = app()->make(GeojsonParser::class);
  // ...

  $geometry = $parser->parse($geojson);
  $transformedGeometry = ST::transform($geometry, srid: 28992, toSrid: 4326);

I think the following is a more expected way it would work:
Preferably no need to pass the default SRID to which to transform to. A default SRID for the app could be set in the config.

  $parser = app()->make(GeojsonParser::class);
  // ...

  $transformedGeometry = $parser->parse($geojson, 28992);

For overriding the defaults we could pass an SRID argument to the GeojsonParser to which the json should be transformed to. Or possilby have this as argument on the parse() method.

  $parser = app()->make(GeojsonParser::class, ['srid' => 4326]);
  // ...
 
  $transformedGeometry = $parser->parse($geojson, 28992);

[saibotk]

Interesting, as far as i am aware geojson is not defined for any other srid and only supports standard 4326.

The documentation is also quite confusing, it says 4326 is required for geojson but also says it can be a different one?

https://postgis.net/docs/ST_AsGeoJSON.html

Do you have any other resources or examples?

[beams]

Interesting timing - I was about to report the very same issue.

We are experiencing the very same issue and trying to figure it out. So we are using OpenLayers for mapping. Everything it creates is in 3857 and the GeoJSON it creates is in 3857.

We are using your GeoJSON parser to convert the data to Magellan objects, but as soon as we do this, it switches to 4326 so we are now unable to store it in the database unless we transform it back again.

[saibotk]

OHHH it uses the SRID via the properties, interesting

https://openlayers.org/en/latest/examples/geojson.html

Yeah we need to implement this. Thanks for reporting, if anyone of you feels like you have the time for implementing the change, i'd be happy to guide you and review your code, though personally im quite busy at the moment and it might take a month or two

[beams]

Ill see what we can do at our end and perhaps send a PR for review. Thanks for the prompt response.

[mauritskorse]

I am getting a lot of data from the Dutch PDOK geodata webservices. All of that can be retrieved in geojson but is in 28992