Issue with GeoFeatureModelSerializer and GeneratedField returning WKT instead of GeoJSON

[QyuBee]

Hi team,

I'm currently using GeoFeatureModelSerializer (from rest_framework_gis) to serialize a model that includes a GeneratedField representing a geographic Point. However, instead of returning a GeoJSON geometry object, the serializer returns a WKT string like this:

        {
            "id": 483602,
            "type": "Feature",
            "geometry": "SRID=4326;POINT (-3.826841 48.576644)",
            "properties": {
                "id_data": "29019_5010_00013",
                "libelle": "13 rue Traverse, 29200 Brest"
            }
        },

Here’s a simplified version of my setup:

point_geo = models.GeneratedField(
    output_field=models.PointField(blank=True, null=True),
    db_persist=True,
    expression=Func(F('lon'), F('lat'), function='ST_MakePoint', output_field=PointField(srid=4326)),
    blank=True,
    null=True
)

This point_geographique field is computed based on available coordinates (lon, lat or x, y) and works fine at the DB level. However, since it's a GeneratedField, it seems like GeoFeatureModelSerializer does not recognize it as a proper geometry field and falls back to a generic model field, which results in the WKT string in the output.

In serializer, if i print the fields, it returns :

'point_geo': ModelField(allow_null=True, model_field=<django.db.models.fields.generated.GeneratedField: point_geo>, read_only=True)

As a workaround, I’ve overridden field in serializer with GeometryField, but it feels like something that should be handled natively if the output field is a PointField.

Is there any plan to support GeneratedField-based geometry fields in future versions of DRF-GIS? Or is there a cleaner approach that I might be missing?

Thanks in advance for your help!

Best regards,

[Jacob Walls]

This sounds like an issue with either djangorestframework's support for GeneratedField in ModelSerializer or the more specific GIS functionality provided by djangorestframework-gis (in its ready() method), not an issue in Django.

As a workaround, I’ve overridden field in serializer with GeometryField, but it feels like something that should be handled natively if the output field is a PointField.

Taking a look at ModelSerializer.serializer_field_mapping in DRF, I don't see any fathoming of GeneratedField, so it's probably a missing feature. You could probably easily subclass that (as well as GeneratedField, e.g. GeneratedGeometryField) to get what you want. Hope that helps!