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import re
from django.contrib.gis.db import models
class BaseSpatialFeatures:
gis_enabled = True
# Does the database contain a SpatialRefSys model to store SRID information?
has_spatialrefsys_table = True
# Does the backend support the django.contrib.gis.utils.add_srs_entry() utility?
supports_add_srs_entry = True
# Does the backend introspect GeometryField to its subtypes?
supports_geometry_field_introspection = True
# Does the database have a geography type?
supports_geography = False
# Does the backend support storing 3D geometries?
supports_3d_storage = False
# Reference implementation of 3D functions is:
# https://postgis.net/docs/PostGIS_Special_Functions_Index.html#PostGIS_3D_Functions
supports_3d_functions = False
# Does the database support SRID transform operations?
supports_transform = True
# Can geometry fields be null?
supports_null_geometries = True
# Are empty geometries supported?
supports_empty_geometries = False
# Can the function be applied on geodetic coordinate systems?
supports_distance_geodetic = True
supports_length_geodetic = True
supports_perimeter_geodetic = False
supports_area_geodetic = True
# Is the database able to count vertices on polygons (with `num_points`)?
supports_num_points_poly = True
# Does the backend support expressions for specifying distance in the
# dwithin lookup?
supports_dwithin_distance_expr = True
# Does the database have raster support?
supports_raster = False
# Does the database support a unique index on geometry fields?
supports_geometry_field_unique_index = True
# Can SchemaEditor alter geometry fields?
can_alter_geometry_field = True
# Do the database functions/aggregates support the tolerance parameter?
supports_tolerance_parameter = False
# Set of options that AsGeoJSON() doesn't support.
unsupported_geojson_options = {}
# Does Intersection() return None (rather than an empty GeometryCollection)
# for empty results?
empty_intersection_returns_none = True
@property
def supports_bbcontains_lookup(self):
return "bbcontains" in self.connection.ops.gis_operators
@property
def supports_contained_lookup(self):
return "contained" in self.connection.ops.gis_operators
@property
def supports_crosses_lookup(self):
return "crosses" in self.connection.ops.gis_operators
@property
def supports_distances_lookups(self):
return self.has_Distance_function
@property
def supports_dwithin_lookup(self):
return "dwithin" in self.connection.ops.gis_operators
@property
def supports_relate_lookup(self):
return "relate" in self.connection.ops.gis_operators
@property
def supports_isvalid_lookup(self):
return self.has_IsValid_function
# Is the aggregate supported by the database?
@property
def supports_collect_aggr(self):
return models.Collect not in self.connection.ops.disallowed_aggregates
@property
def supports_extent_aggr(self):
return models.Extent not in self.connection.ops.disallowed_aggregates
@property
def supports_make_line_aggr(self):
return models.MakeLine not in self.connection.ops.disallowed_aggregates
@property
def supports_union_aggr(self):
return models.Union not in self.connection.ops.disallowed_aggregates
def __getattr__(self, name):
m = re.match(r"has_(\w*)_function$", name)
if m:
func_name = m[1]
return func_name not in self.connection.ops.unsupported_functions
raise AttributeError
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