Method check_layer

django/contrib/gis/utils/layermapping.py:192–308

Check the Layer metadata and ensure that it's compatible with the mapping information and model. Unlike previous revisions, there is no need to increment through each feature in the Layer.

(self)

            return None

    def check_layer(self):
        """
        Check the Layer metadata and ensure that it's compatible with the
        mapping information and model. Unlike previous revisions, there is no
        need to increment through each feature in the Layer.
        """
        # The geometry field of the model is set here.
        # TODO: Support more than one geometry field / model. However, this
        # depends on the GDAL Driver in use.
        self.geom_field = False
        self.fields = {}

        # Getting lists of the field names and the field types available in
        # the OGR Layer.
        ogr_fields = self.layer.fields
        ogr_field_types = self.layer.field_types

        # Function for determining if the OGR mapping field is in the Layer.
        def check_ogr_fld(ogr_map_fld):
            try:
                idx = ogr_fields.index(ogr_map_fld)
            except ValueError:
                raise LayerMapError(
                    'Given mapping OGR field "%s" not found in OGR Layer.' % ogr_map_fld
                )
            return idx

        # No need to increment through each feature in the model, simply check
        # the Layer metadata against what was given in the mapping dictionary.
        for field_name, ogr_name in self.mapping.items():
            # Ensuring that a corresponding field exists in the model
            # for the given field name in the mapping.
            try:
                model_field = self.model._meta.get_field(field_name)
            except FieldDoesNotExist:
                raise LayerMapError(
                    'Given mapping field "%s" not in given Model fields.' % field_name
                )

            # Getting the string name for the Django field class (e.g.,
            # 'PointField').
            fld_name = model_field.__class__.__name__

            if isinstance(model_field, GeometryField):
                if self.geom_field:
                    raise LayerMapError(
                        "LayerMapping does not support more than one GeometryField per "
                        "model."
                    )

                # Getting the coordinate dimension of the geometry field.
                coord_dim = model_field.dim

                try:
                    if coord_dim == 3:
                        gtype = OGRGeomType(ogr_name + "25D")
                    else:
                        gtype = OGRGeomType(ogr_name)