def area(self, tolerance=0.05, **kwargs):
"""
Returns the area of the geographic field in an `area` attribute on
each element of this GeoQuerySet.
"""
# Performing setup here rather than in `_spatial_attribute` so that
# we can get the units for `AreaField`.
procedure_args, geo_field = self._spatial_setup(
'area', field_name=kwargs.get('field_name'))
s = {'procedure_args': procedure_args,
'geo_field': geo_field,
'setup': False,
}
connection = connections[self.db]
backend = connection.ops
if backend.oracle:
s['procedure_fmt'] = '%(geo_col)s,%(tolerance)s'
s['procedure_args']['tolerance'] = tolerance
s['select_field'] = AreaField('sq_m') # Oracle returns area in units of meters.
elif backend.postgis or backend.spatialite:
if backend.geography:
# Geography fields support area calculation, returns square meters.
s['select_field'] = AreaField('sq_m')
elif not geo_field.geodetic(connection):
# Getting the area units of the geographic field.
s['select_field'] = AreaField(Area.unit_attname(geo_field.units_name(connection)))
else:
# TODO: Do we want to support raw number areas for geodetic fields?
raise Exception('Area on geodetic coordinate systems not supported.')
return self._spatial_attribute('area', s, **kwargs)
class Area(OracleToleranceMixin, GeoFunc):
arity = 1
def as_sql(self, compiler, connection):
if connection.ops.geography:
# Geography fields support area calculation, returns square meters.
self.output_field = AreaField('sq_m')
elif not self.output_field.geodetic(connection):
# Getting the area units of the geographic field.
units = self.output_field.units_name(connection)
if units:
self.output_field = AreaField(
AreaMeasure.unit_attname(
self.output_field.units_name(connection)))
else:
self.output_field = FloatField()
else:
# TODO: Do we want to support raw number areas for geodetic fields?
raise NotImplementedError(
'Area on geodetic coordinate systems not supported.')
return super(Area, self).as_sql(compiler, connection)
def as_oracle(self, compiler, connection):
self.output_field = AreaField(
'sq_m') # Oracle returns area in units of meters.
return super(Area, self).as_oracle(compiler, connection)
def as_sql(self, compiler, connection):
if connection.ops.geography:
# Geography fields support area calculation, returns square meters.
self.output_field = AreaField("sq_m")
elif not self.output_field.geodetic(connection):
# Getting the area units of the geographic field.
units = self.output_field.units_name(connection)
if units:
self.output_field = AreaField(AreaMeasure.unit_attname(self.output_field.units_name(connection)))
else:
self.output_field = FloatField()
else:
# TODO: Do we want to support raw number areas for geodetic fields?
raise NotImplementedError("Area on geodetic coordinate systems not supported.")
return super(Area, self).as_sql(compiler, connection)
class Area(OracleToleranceMixin, GeoFunc):
arity = 1
def as_sql(self, compiler, connection):
if connection.ops.geography:
# Geography fields support area calculation, returns square meters.
self.output_field = AreaField('sq_m')
elif not self.output_field.geodetic(connection):
# Getting the area units of the geographic field.
units = self.output_field.units_name(connection)
if units:
self.output_field = AreaField(
AreaMeasure.unit_attname(self.output_field.units_name(connection))
)
else:
self.output_field = FloatField()
else:
# TODO: Do we want to support raw number areas for geodetic fields?
raise NotImplementedError('Area on geodetic coordinate systems not supported.')
return super(Area, self).as_sql(compiler, connection)
def as_oracle(self, compiler, connection):
self.output_field = AreaField('sq_m') # Oracle returns area in units of meters.
return super(Area, self).as_oracle(compiler, connection)
def as_oracle(self, compiler, connection):
self.output_field = AreaField(
'sq_m') # Oracle returns area in units of meters.
return super(Area, self).as_oracle(compiler, connection)
def output_field(self):
return AreaField(self.geo_field)
def as_oracle(self, compiler, connection):
self.output_field = AreaField('sq_m') # Oracle returns area in units of meters.
return super(Area, self).as_oracle(compiler, connection)
def test_area_field_deepcopy(self):
field = AreaField(None)
self.assertEqual(copy.deepcopy(field), field)
from decimal import Decimal
