# Django 4.2.9.dev20231204082947 - dokumentacja

# `GeoJSON` Serializer

GeoDjango provides a specific serializer for the GeoJSON format. See Serializing Django objects for more information on serialization.

The `geojson` serializer is not meant for round-tripping data, as it has no deserializer equivalent. For example, you cannot use `loaddata` to reload the output produced by this serializer. If you plan to reload the outputted data, use the plain json serializer instead.

In addition to the options of the `json` serializer, the `geojson` serializer accepts the following additional option when it is called by `serializers.serialize()`:

- `geometry_field`: A string containing the name of a geometry field to use for the `geometry` key of the GeoJSON feature. This is only needed when you have a model with more than one geometry field and you don’t want to use the first defined geometry field (by default, the first geometry field is picked).
- `id_field`: A string containing the name of a field to use for the `id` key of the GeoJSON feature. By default, the primary key of objects is used.
- `srid`: The SRID to use for the `geometry` content. Defaults to 4326 (WGS 84).

The fields option can be used to limit fields that will be present in the `properties` key, as it works with all other serializers.

Example:

    from django.core.serializers import serialize
    from my_app.models import City

    serialize("geojson", City.objects.all(), geometry_field="point", fields=["name"])

Would output:

    {
        "type": "FeatureCollection",
        "crs": {"type": "name", "properties": {"name": "EPSG:4326"}},
        "features": [
            {
                "type": "Feature",
                "id": 1,
                "geometry": {"type": "Point", "coordinates": [-87.650175, 41.850385]},
                "properties": {"name": "Chicago"},
            }
        ],
    }

When the `fields` parameter is not specified, the `geojson` serializer adds a `pk` key to the `properties` dictionary with the primary key of the object as the value.

Changed in Django 4.2:

The `id` key for serialized features was added. Also, the `id_field` option was added to the `geojson` serializer.