本文整理汇总了Python中django.contrib.gis.db.models.sql.AreaField方法的典型用法代码示例。如果您正苦于以下问题：Python sql.AreaField方法的具体用法？Python sql.AreaField怎么用？Python sql.AreaField使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类django.contrib.gis.db.models.sql的用法示例。
在下文中一共展示了sql.AreaField方法的3个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: as_sql
# 需要导入模块: from django.contrib.gis.db.models import sql [as 别名]
# 或者: from django.contrib.gis.db.models.sql import AreaField [as 别名]
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) 示例2: as_oracle
# 需要导入模块: from django.contrib.gis.db.models import sql [as 别名]
# 或者: from django.contrib.gis.db.models.sql import AreaField [as 别名]
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) 示例3: area
# 需要导入模块: from django.contrib.gis.db.models import sql [as 别名]
# 或者: from django.contrib.gis.db.models.sql import AreaField [as 别名]
def area(self, tolerance=0.05, **kwargs):
"""
Returns the area of the geographic field in an `area` attribute on
each element of this GeoQuerySet.
"""
# Peforming 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', None))
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)