782 lines
35 KiB
Python
782 lines
35 KiB
Python
from django.db import connections
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from django.db.models.query import QuerySet, ValuesQuerySet, ValuesListQuerySet
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from django.contrib.gis import memoryview
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from django.contrib.gis.db.models import aggregates
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from django.contrib.gis.db.models.fields import get_srid_info, PointField, LineStringField
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from django.contrib.gis.db.models.sql import AreaField, DistanceField, GeomField, GeoQuery
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from django.contrib.gis.geometry.backend import Geometry
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from django.contrib.gis.measure import Area, Distance
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from django.utils import six
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class GeoQuerySet(QuerySet):
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"The Geographic QuerySet."
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### Methods overloaded from QuerySet ###
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def __init__(self, model=None, query=None, using=None):
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super(GeoQuerySet, self).__init__(model=model, query=query, using=using)
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self.query = query or GeoQuery(self.model)
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def values(self, *fields):
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return self._clone(klass=GeoValuesQuerySet, setup=True, _fields=fields)
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def values_list(self, *fields, **kwargs):
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flat = kwargs.pop('flat', False)
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if kwargs:
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raise TypeError('Unexpected keyword arguments to values_list: %s'
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% (list(kwargs),))
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if flat and len(fields) > 1:
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raise TypeError("'flat' is not valid when values_list is called with more than one field.")
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return self._clone(klass=GeoValuesListQuerySet, setup=True, flat=flat,
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_fields=fields)
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### GeoQuerySet Methods ###
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def area(self, tolerance=0.05, **kwargs):
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"""
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Returns the area of the geographic field in an `area` attribute on
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each element of this GeoQuerySet.
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"""
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# Peforming setup here rather than in `_spatial_attribute` so that
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# we can get the units for `AreaField`.
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procedure_args, geo_field = self._spatial_setup('area', field_name=kwargs.get('field_name', None))
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s = {'procedure_args' : procedure_args,
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'geo_field' : geo_field,
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'setup' : False,
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}
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connection = connections[self.db]
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backend = connection.ops
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if backend.oracle:
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s['procedure_fmt'] = '%(geo_col)s,%(tolerance)s'
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s['procedure_args']['tolerance'] = tolerance
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s['select_field'] = AreaField('sq_m') # Oracle returns area in units of meters.
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elif backend.postgis or backend.spatialite:
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if backend.geography:
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# Geography fields support area calculation, returns square meters.
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s['select_field'] = AreaField('sq_m')
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elif not geo_field.geodetic(connection):
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# Getting the area units of the geographic field.
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s['select_field'] = AreaField(Area.unit_attname(geo_field.units_name(connection)))
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else:
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# TODO: Do we want to support raw number areas for geodetic fields?
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raise Exception('Area on geodetic coordinate systems not supported.')
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return self._spatial_attribute('area', s, **kwargs)
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def centroid(self, **kwargs):
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"""
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Returns the centroid of the geographic field in a `centroid`
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attribute on each element of this GeoQuerySet.
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"""
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return self._geom_attribute('centroid', **kwargs)
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def collect(self, **kwargs):
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"""
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Performs an aggregate collect operation on the given geometry field.
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This is analagous to a union operation, but much faster because
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boundaries are not dissolved.
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"""
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return self._spatial_aggregate(aggregates.Collect, **kwargs)
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def difference(self, geom, **kwargs):
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"""
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Returns the spatial difference of the geographic field in a `difference`
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attribute on each element of this GeoQuerySet.
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"""
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return self._geomset_attribute('difference', geom, **kwargs)
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def distance(self, geom, **kwargs):
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"""
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Returns the distance from the given geographic field name to the
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given geometry in a `distance` attribute on each element of the
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GeoQuerySet.
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Keyword Arguments:
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`spheroid` => If the geometry field is geodetic and PostGIS is
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the spatial database, then the more accurate
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spheroid calculation will be used instead of the
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quicker sphere calculation.
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`tolerance` => Used only for Oracle. The tolerance is
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in meters -- a default of 5 centimeters (0.05)
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is used.
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"""
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return self._distance_attribute('distance', geom, **kwargs)
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def envelope(self, **kwargs):
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"""
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Returns a Geometry representing the bounding box of the
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Geometry field in an `envelope` attribute on each element of
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the GeoQuerySet.
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"""
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return self._geom_attribute('envelope', **kwargs)
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def extent(self, **kwargs):
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"""
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Returns the extent (aggregate) of the features in the GeoQuerySet. The
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extent will be returned as a 4-tuple, consisting of (xmin, ymin, xmax, ymax).
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"""
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return self._spatial_aggregate(aggregates.Extent, **kwargs)
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def extent3d(self, **kwargs):
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"""
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Returns the aggregate extent, in 3D, of the features in the
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GeoQuerySet. It is returned as a 6-tuple, comprising:
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(xmin, ymin, zmin, xmax, ymax, zmax).
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"""
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return self._spatial_aggregate(aggregates.Extent3D, **kwargs)
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def force_rhr(self, **kwargs):
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"""
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Returns a modified version of the Polygon/MultiPolygon in which
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all of the vertices follow the Right-Hand-Rule. By default,
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this is attached as the `force_rhr` attribute on each element
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of the GeoQuerySet.
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"""
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return self._geom_attribute('force_rhr', **kwargs)
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def geojson(self, precision=8, crs=False, bbox=False, **kwargs):
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"""
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Returns a GeoJSON representation of the geomtry field in a `geojson`
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attribute on each element of the GeoQuerySet.
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The `crs` and `bbox` keywords may be set to True if the users wants
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the coordinate reference system and the bounding box to be included
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in the GeoJSON representation of the geometry.
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"""
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backend = connections[self.db].ops
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if not backend.geojson:
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raise NotImplementedError('Only PostGIS 1.3.4+ supports GeoJSON serialization.')
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if not isinstance(precision, six.integer_types):
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raise TypeError('Precision keyword must be set with an integer.')
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# Setting the options flag -- which depends on which version of
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# PostGIS we're using.
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if backend.spatial_version >= (1, 4, 0):
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options = 0
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if crs and bbox: options = 3
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elif bbox: options = 1
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elif crs: options = 2
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else:
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options = 0
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if crs and bbox: options = 3
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elif crs: options = 1
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elif bbox: options = 2
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s = {'desc' : 'GeoJSON',
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'procedure_args' : {'precision' : precision, 'options' : options},
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'procedure_fmt' : '%(geo_col)s,%(precision)s,%(options)s',
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}
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return self._spatial_attribute('geojson', s, **kwargs)
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def geohash(self, precision=20, **kwargs):
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"""
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Returns a GeoHash representation of the given field in a `geohash`
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attribute on each element of the GeoQuerySet.
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The `precision` keyword may be used to custom the number of
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_characters_ used in the output GeoHash, the default is 20.
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"""
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s = {'desc' : 'GeoHash',
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'procedure_args': {'precision': precision},
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'procedure_fmt': '%(geo_col)s,%(precision)s',
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}
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return self._spatial_attribute('geohash', s, **kwargs)
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def gml(self, precision=8, version=2, **kwargs):
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"""
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Returns GML representation of the given field in a `gml` attribute
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on each element of the GeoQuerySet.
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"""
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backend = connections[self.db].ops
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s = {'desc' : 'GML', 'procedure_args' : {'precision' : precision}}
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if backend.postgis:
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# PostGIS AsGML() aggregate function parameter order depends on the
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# version -- uggh.
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if backend.spatial_version > (1, 3, 1):
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procedure_fmt = '%(version)s,%(geo_col)s,%(precision)s'
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else:
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procedure_fmt = '%(geo_col)s,%(precision)s,%(version)s'
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s['procedure_args'] = {'precision' : precision, 'version' : version}
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return self._spatial_attribute('gml', s, **kwargs)
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def intersection(self, geom, **kwargs):
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"""
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Returns the spatial intersection of the Geometry field in
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an `intersection` attribute on each element of this
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GeoQuerySet.
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"""
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return self._geomset_attribute('intersection', geom, **kwargs)
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def kml(self, **kwargs):
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"""
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Returns KML representation of the geometry field in a `kml`
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attribute on each element of this GeoQuerySet.
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"""
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s = {'desc' : 'KML',
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'procedure_fmt' : '%(geo_col)s,%(precision)s',
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'procedure_args' : {'precision' : kwargs.pop('precision', 8)},
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}
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return self._spatial_attribute('kml', s, **kwargs)
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def length(self, **kwargs):
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"""
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Returns the length of the geometry field as a `Distance` object
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stored in a `length` attribute on each element of this GeoQuerySet.
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"""
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return self._distance_attribute('length', None, **kwargs)
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def make_line(self, **kwargs):
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"""
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Creates a linestring from all of the PointField geometries in the
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this GeoQuerySet and returns it. This is a spatial aggregate
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method, and thus returns a geometry rather than a GeoQuerySet.
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"""
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return self._spatial_aggregate(aggregates.MakeLine, geo_field_type=PointField, **kwargs)
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def mem_size(self, **kwargs):
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"""
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Returns the memory size (number of bytes) that the geometry field takes
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in a `mem_size` attribute on each element of this GeoQuerySet.
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"""
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return self._spatial_attribute('mem_size', {}, **kwargs)
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def num_geom(self, **kwargs):
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"""
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Returns the number of geometries if the field is a
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GeometryCollection or Multi* Field in a `num_geom`
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attribute on each element of this GeoQuerySet; otherwise
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the sets with None.
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"""
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return self._spatial_attribute('num_geom', {}, **kwargs)
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def num_points(self, **kwargs):
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"""
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Returns the number of points in the first linestring in the
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Geometry field in a `num_points` attribute on each element of
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this GeoQuerySet; otherwise sets with None.
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"""
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return self._spatial_attribute('num_points', {}, **kwargs)
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def perimeter(self, **kwargs):
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"""
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Returns the perimeter of the geometry field as a `Distance` object
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stored in a `perimeter` attribute on each element of this GeoQuerySet.
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"""
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return self._distance_attribute('perimeter', None, **kwargs)
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def point_on_surface(self, **kwargs):
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"""
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Returns a Point geometry guaranteed to lie on the surface of the
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Geometry field in a `point_on_surface` attribute on each element
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of this GeoQuerySet; otherwise sets with None.
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"""
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return self._geom_attribute('point_on_surface', **kwargs)
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def reverse_geom(self, **kwargs):
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"""
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Reverses the coordinate order of the geometry, and attaches as a
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`reverse` attribute on each element of this GeoQuerySet.
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"""
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s = {'select_field' : GeomField(),}
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kwargs.setdefault('model_att', 'reverse_geom')
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if connections[self.db].ops.oracle:
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s['geo_field_type'] = LineStringField
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return self._spatial_attribute('reverse', s, **kwargs)
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def scale(self, x, y, z=0.0, **kwargs):
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"""
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Scales the geometry to a new size by multiplying the ordinates
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with the given x,y,z scale factors.
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"""
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if connections[self.db].ops.spatialite:
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if z != 0.0:
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raise NotImplementedError('SpatiaLite does not support 3D scaling.')
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s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s',
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'procedure_args' : {'x' : x, 'y' : y},
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'select_field' : GeomField(),
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}
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else:
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s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s,%(z)s',
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'procedure_args' : {'x' : x, 'y' : y, 'z' : z},
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'select_field' : GeomField(),
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}
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return self._spatial_attribute('scale', s, **kwargs)
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def snap_to_grid(self, *args, **kwargs):
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"""
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Snap all points of the input geometry to the grid. How the
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geometry is snapped to the grid depends on how many arguments
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were given:
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- 1 argument : A single size to snap both the X and Y grids to.
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- 2 arguments: X and Y sizes to snap the grid to.
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- 4 arguments: X, Y sizes and the X, Y origins.
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"""
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if False in [isinstance(arg, (float,) + six.integer_types) for arg in args]:
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raise TypeError('Size argument(s) for the grid must be a float or integer values.')
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nargs = len(args)
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if nargs == 1:
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size = args[0]
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procedure_fmt = '%(geo_col)s,%(size)s'
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procedure_args = {'size' : size}
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elif nargs == 2:
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xsize, ysize = args
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procedure_fmt = '%(geo_col)s,%(xsize)s,%(ysize)s'
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procedure_args = {'xsize' : xsize, 'ysize' : ysize}
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elif nargs == 4:
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xsize, ysize, xorigin, yorigin = args
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procedure_fmt = '%(geo_col)s,%(xorigin)s,%(yorigin)s,%(xsize)s,%(ysize)s'
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procedure_args = {'xsize' : xsize, 'ysize' : ysize,
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'xorigin' : xorigin, 'yorigin' : yorigin}
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else:
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raise ValueError('Must provide 1, 2, or 4 arguments to `snap_to_grid`.')
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s = {'procedure_fmt' : procedure_fmt,
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'procedure_args' : procedure_args,
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'select_field' : GeomField(),
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}
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return self._spatial_attribute('snap_to_grid', s, **kwargs)
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def svg(self, relative=False, precision=8, **kwargs):
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"""
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Returns SVG representation of the geographic field in a `svg`
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attribute on each element of this GeoQuerySet.
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Keyword Arguments:
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`relative` => If set to True, this will evaluate the path in
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terms of relative moves (rather than absolute).
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`precision` => May be used to set the maximum number of decimal
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digits used in output (defaults to 8).
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"""
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relative = int(bool(relative))
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if not isinstance(precision, six.integer_types):
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raise TypeError('SVG precision keyword argument must be an integer.')
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s = {'desc' : 'SVG',
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'procedure_fmt' : '%(geo_col)s,%(rel)s,%(precision)s',
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'procedure_args' : {'rel' : relative,
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'precision' : precision,
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}
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}
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return self._spatial_attribute('svg', s, **kwargs)
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def sym_difference(self, geom, **kwargs):
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"""
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Returns the symmetric difference of the geographic field in a
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`sym_difference` attribute on each element of this GeoQuerySet.
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"""
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return self._geomset_attribute('sym_difference', geom, **kwargs)
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def translate(self, x, y, z=0.0, **kwargs):
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"""
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Translates the geometry to a new location using the given numeric
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parameters as offsets.
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"""
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if connections[self.db].ops.spatialite:
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if z != 0.0:
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raise NotImplementedError('SpatiaLite does not support 3D translation.')
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s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s',
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'procedure_args' : {'x' : x, 'y' : y},
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'select_field' : GeomField(),
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}
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else:
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s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s,%(z)s',
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'procedure_args' : {'x' : x, 'y' : y, 'z' : z},
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'select_field' : GeomField(),
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}
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return self._spatial_attribute('translate', s, **kwargs)
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def transform(self, srid=4326, **kwargs):
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"""
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Transforms the given geometry field to the given SRID. If no SRID is
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provided, the transformation will default to using 4326 (WGS84).
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"""
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if not isinstance(srid, six.integer_types):
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raise TypeError('An integer SRID must be provided.')
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field_name = kwargs.get('field_name', None)
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tmp, geo_field = self._spatial_setup('transform', field_name=field_name)
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# Getting the selection SQL for the given geographic field.
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field_col = self._geocol_select(geo_field, field_name)
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# Why cascading substitutions? Because spatial backends like
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# Oracle and MySQL already require a function call to convert to text, thus
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# when there's also a transformation we need to cascade the substitutions.
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# For example, 'SDO_UTIL.TO_WKTGEOMETRY(SDO_CS.TRANSFORM( ... )'
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geo_col = self.query.custom_select.get(geo_field, field_col)
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# Setting the key for the field's column with the custom SELECT SQL to
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# override the geometry column returned from the database.
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custom_sel = '%s(%s, %s)' % (connections[self.db].ops.transform, geo_col, srid)
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# TODO: Should we have this as an alias?
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# custom_sel = '(%s(%s, %s)) AS %s' % (SpatialBackend.transform, geo_col, srid, qn(geo_field.name))
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self.query.transformed_srid = srid # So other GeoQuerySet methods
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self.query.custom_select[geo_field] = custom_sel
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return self._clone()
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def union(self, geom, **kwargs):
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"""
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Returns the union of the geographic field with the given
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Geometry in a `union` attribute on each element of this GeoQuerySet.
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"""
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return self._geomset_attribute('union', geom, **kwargs)
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def unionagg(self, **kwargs):
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"""
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Performs an aggregate union on the given geometry field. Returns
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None if the GeoQuerySet is empty. The `tolerance` keyword is for
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Oracle backends only.
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"""
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return self._spatial_aggregate(aggregates.Union, **kwargs)
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### Private API -- Abstracted DRY routines. ###
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def _spatial_setup(self, att, desc=None, field_name=None, geo_field_type=None):
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"""
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Performs set up for executing the spatial function.
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"""
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# Does the spatial backend support this?
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connection = connections[self.db]
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func = getattr(connection.ops, att, False)
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if desc is None: desc = att
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if not func:
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raise NotImplementedError('%s stored procedure not available on '
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'the %s backend.' %
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(desc, connection.ops.name))
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# Initializing the procedure arguments.
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procedure_args = {'function' : func}
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# Is there a geographic field in the model to perform this
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# operation on?
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geo_field = self.query._geo_field(field_name)
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if not geo_field:
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raise TypeError('%s output only available on GeometryFields.' % func)
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# If the `geo_field_type` keyword was used, then enforce that
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# type limitation.
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if not geo_field_type is None and not isinstance(geo_field, geo_field_type):
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raise TypeError('"%s" stored procedures may only be called on %ss.' % (func, geo_field_type.__name__))
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# Setting the procedure args.
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procedure_args['geo_col'] = self._geocol_select(geo_field, field_name)
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return procedure_args, geo_field
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def _spatial_aggregate(self, aggregate, field_name=None,
|
|
geo_field_type=None, tolerance=0.05):
|
|
"""
|
|
DRY routine for calling aggregate spatial stored procedures and
|
|
returning their result to the caller of the function.
|
|
"""
|
|
# Getting the field the geographic aggregate will be called on.
|
|
geo_field = self.query._geo_field(field_name)
|
|
if not geo_field:
|
|
raise TypeError('%s aggregate only available on GeometryFields.' % aggregate.name)
|
|
|
|
# Checking if there are any geo field type limitations on this
|
|
# aggregate (e.g. ST_Makeline only operates on PointFields).
|
|
if not geo_field_type is None and not isinstance(geo_field, geo_field_type):
|
|
raise TypeError('%s aggregate may only be called on %ss.' % (aggregate.name, geo_field_type.__name__))
|
|
|
|
# Getting the string expression of the field name, as this is the
|
|
# argument taken by `Aggregate` objects.
|
|
agg_col = field_name or geo_field.name
|
|
|
|
# Adding any keyword parameters for the Aggregate object. Oracle backends
|
|
# in particular need an additional `tolerance` parameter.
|
|
agg_kwargs = {}
|
|
if connections[self.db].ops.oracle: agg_kwargs['tolerance'] = tolerance
|
|
|
|
# Calling the QuerySet.aggregate, and returning only the value of the aggregate.
|
|
return self.aggregate(geoagg=aggregate(agg_col, **agg_kwargs))['geoagg']
|
|
|
|
def _spatial_attribute(self, att, settings, field_name=None, model_att=None):
|
|
"""
|
|
DRY routine for calling a spatial stored procedure on a geometry column
|
|
and attaching its output as an attribute of the model.
|
|
|
|
Arguments:
|
|
att:
|
|
The name of the spatial attribute that holds the spatial
|
|
SQL function to call.
|
|
|
|
settings:
|
|
Dictonary of internal settings to customize for the spatial procedure.
|
|
|
|
Public Keyword Arguments:
|
|
|
|
field_name:
|
|
The name of the geographic field to call the spatial
|
|
function on. May also be a lookup to a geometry field
|
|
as part of a foreign key relation.
|
|
|
|
model_att:
|
|
The name of the model attribute to attach the output of
|
|
the spatial function to.
|
|
"""
|
|
# Default settings.
|
|
settings.setdefault('desc', None)
|
|
settings.setdefault('geom_args', ())
|
|
settings.setdefault('geom_field', None)
|
|
settings.setdefault('procedure_args', {})
|
|
settings.setdefault('procedure_fmt', '%(geo_col)s')
|
|
settings.setdefault('select_params', [])
|
|
|
|
connection = connections[self.db]
|
|
backend = connection.ops
|
|
|
|
# Performing setup for the spatial column, unless told not to.
|
|
if settings.get('setup', True):
|
|
default_args, geo_field = self._spatial_setup(att, desc=settings['desc'], field_name=field_name,
|
|
geo_field_type=settings.get('geo_field_type', None))
|
|
for k, v in six.iteritems(default_args): settings['procedure_args'].setdefault(k, v)
|
|
else:
|
|
geo_field = settings['geo_field']
|
|
|
|
# The attribute to attach to the model.
|
|
if not isinstance(model_att, six.string_types): model_att = att
|
|
|
|
# Special handling for any argument that is a geometry.
|
|
for name in settings['geom_args']:
|
|
# Using the field's get_placeholder() routine to get any needed
|
|
# transformation SQL.
|
|
geom = geo_field.get_prep_value(settings['procedure_args'][name])
|
|
params = geo_field.get_db_prep_lookup('contains', geom, connection=connection)
|
|
geom_placeholder = geo_field.get_placeholder(geom, connection)
|
|
|
|
# Replacing the procedure format with that of any needed
|
|
# transformation SQL.
|
|
old_fmt = '%%(%s)s' % name
|
|
new_fmt = geom_placeholder % '%%s'
|
|
settings['procedure_fmt'] = settings['procedure_fmt'].replace(old_fmt, new_fmt)
|
|
settings['select_params'].extend(params)
|
|
|
|
# Getting the format for the stored procedure.
|
|
fmt = '%%(function)s(%s)' % settings['procedure_fmt']
|
|
|
|
# If the result of this function needs to be converted.
|
|
if settings.get('select_field', False):
|
|
sel_fld = settings['select_field']
|
|
if isinstance(sel_fld, GeomField) and backend.select:
|
|
self.query.custom_select[model_att] = backend.select
|
|
if connection.ops.oracle:
|
|
sel_fld.empty_strings_allowed = False
|
|
self.query.extra_select_fields[model_att] = sel_fld
|
|
|
|
# Finally, setting the extra selection attribute with
|
|
# the format string expanded with the stored procedure
|
|
# arguments.
|
|
return self.extra(select={model_att : fmt % settings['procedure_args']},
|
|
select_params=settings['select_params'])
|
|
|
|
def _distance_attribute(self, func, geom=None, tolerance=0.05, spheroid=False, **kwargs):
|
|
"""
|
|
DRY routine for GeoQuerySet distance attribute routines.
|
|
"""
|
|
# Setting up the distance procedure arguments.
|
|
procedure_args, geo_field = self._spatial_setup(func, field_name=kwargs.get('field_name', None))
|
|
|
|
# If geodetic defaulting distance attribute to meters (Oracle and
|
|
# PostGIS spherical distances return meters). Otherwise, use the
|
|
# units of the geometry field.
|
|
connection = connections[self.db]
|
|
geodetic = geo_field.geodetic(connection)
|
|
geography = geo_field.geography
|
|
|
|
if geodetic:
|
|
dist_att = 'm'
|
|
else:
|
|
dist_att = Distance.unit_attname(geo_field.units_name(connection))
|
|
|
|
# Shortcut booleans for what distance function we're using and
|
|
# whether the geometry field is 3D.
|
|
distance = func == 'distance'
|
|
length = func == 'length'
|
|
perimeter = func == 'perimeter'
|
|
if not (distance or length or perimeter):
|
|
raise ValueError('Unknown distance function: %s' % func)
|
|
geom_3d = geo_field.dim == 3
|
|
|
|
# The field's get_db_prep_lookup() is used to get any
|
|
# extra distance parameters. Here we set up the
|
|
# parameters that will be passed in to field's function.
|
|
lookup_params = [geom or 'POINT (0 0)', 0]
|
|
|
|
# Getting the spatial backend operations.
|
|
backend = connection.ops
|
|
|
|
# If the spheroid calculation is desired, either by the `spheroid`
|
|
# keyword or when calculating the length of geodetic field, make
|
|
# sure the 'spheroid' distance setting string is passed in so we
|
|
# get the correct spatial stored procedure.
|
|
if spheroid or (backend.postgis and geodetic and
|
|
(not geography) and length):
|
|
lookup_params.append('spheroid')
|
|
lookup_params = geo_field.get_prep_value(lookup_params)
|
|
params = geo_field.get_db_prep_lookup('distance_lte', lookup_params, connection=connection)
|
|
|
|
# The `geom_args` flag is set to true if a geometry parameter was
|
|
# passed in.
|
|
geom_args = bool(geom)
|
|
|
|
if backend.oracle:
|
|
if distance:
|
|
procedure_fmt = '%(geo_col)s,%(geom)s,%(tolerance)s'
|
|
elif length or perimeter:
|
|
procedure_fmt = '%(geo_col)s,%(tolerance)s'
|
|
procedure_args['tolerance'] = tolerance
|
|
else:
|
|
# Getting whether this field is in units of degrees since the field may have
|
|
# been transformed via the `transform` GeoQuerySet method.
|
|
if self.query.transformed_srid:
|
|
u, unit_name, s = get_srid_info(self.query.transformed_srid, connection)
|
|
geodetic = unit_name in geo_field.geodetic_units
|
|
|
|
if backend.spatialite and geodetic:
|
|
raise ValueError('SQLite does not support linear distance calculations on geodetic coordinate systems.')
|
|
|
|
if distance:
|
|
if self.query.transformed_srid:
|
|
# Setting the `geom_args` flag to false because we want to handle
|
|
# transformation SQL here, rather than the way done by default
|
|
# (which will transform to the original SRID of the field rather
|
|
# than to what was transformed to).
|
|
geom_args = False
|
|
procedure_fmt = '%s(%%(geo_col)s, %s)' % (backend.transform, self.query.transformed_srid)
|
|
if geom.srid is None or geom.srid == self.query.transformed_srid:
|
|
# If the geom parameter srid is None, it is assumed the coordinates
|
|
# are in the transformed units. A placeholder is used for the
|
|
# geometry parameter. `GeomFromText` constructor is also needed
|
|
# to wrap geom placeholder for SpatiaLite.
|
|
if backend.spatialite:
|
|
procedure_fmt += ', %s(%%%%s, %s)' % (backend.from_text, self.query.transformed_srid)
|
|
else:
|
|
procedure_fmt += ', %%s'
|
|
else:
|
|
# We need to transform the geom to the srid specified in `transform()`,
|
|
# so wrapping the geometry placeholder in transformation SQL.
|
|
# SpatiaLite also needs geometry placeholder wrapped in `GeomFromText`
|
|
# constructor.
|
|
if backend.spatialite:
|
|
procedure_fmt += ', %s(%s(%%%%s, %s), %s)' % (backend.transform, backend.from_text,
|
|
geom.srid, self.query.transformed_srid)
|
|
else:
|
|
procedure_fmt += ', %s(%%%%s, %s)' % (backend.transform, self.query.transformed_srid)
|
|
else:
|
|
# `transform()` was not used on this GeoQuerySet.
|
|
procedure_fmt = '%(geo_col)s,%(geom)s'
|
|
|
|
if not geography and geodetic:
|
|
# Spherical distance calculation is needed (because the geographic
|
|
# field is geodetic). However, the PostGIS ST_distance_sphere/spheroid()
|
|
# procedures may only do queries from point columns to point geometries
|
|
# some error checking is required.
|
|
if not backend.geography:
|
|
if not isinstance(geo_field, PointField):
|
|
raise ValueError('Spherical distance calculation only supported on PointFields.')
|
|
if not str(Geometry(memoryview(params[0].ewkb)).geom_type) == 'Point':
|
|
raise ValueError('Spherical distance calculation only supported with Point Geometry parameters')
|
|
# The `function` procedure argument needs to be set differently for
|
|
# geodetic distance calculations.
|
|
if spheroid:
|
|
# Call to distance_spheroid() requires spheroid param as well.
|
|
procedure_fmt += ",'%(spheroid)s'"
|
|
procedure_args.update({'function' : backend.distance_spheroid, 'spheroid' : params[1]})
|
|
else:
|
|
procedure_args.update({'function' : backend.distance_sphere})
|
|
elif length or perimeter:
|
|
procedure_fmt = '%(geo_col)s'
|
|
if not geography and geodetic and length:
|
|
# There's no `length_sphere`, and `length_spheroid` also
|
|
# works on 3D geometries.
|
|
procedure_fmt += ",'%(spheroid)s'"
|
|
procedure_args.update({'function' : backend.length_spheroid, 'spheroid' : params[1]})
|
|
elif geom_3d and backend.postgis:
|
|
# Use 3D variants of perimeter and length routines on PostGIS.
|
|
if perimeter:
|
|
procedure_args.update({'function' : backend.perimeter3d})
|
|
elif length:
|
|
procedure_args.update({'function' : backend.length3d})
|
|
|
|
# Setting up the settings for `_spatial_attribute`.
|
|
s = {'select_field' : DistanceField(dist_att),
|
|
'setup' : False,
|
|
'geo_field' : geo_field,
|
|
'procedure_args' : procedure_args,
|
|
'procedure_fmt' : procedure_fmt,
|
|
}
|
|
if geom_args:
|
|
s['geom_args'] = ('geom',)
|
|
s['procedure_args']['geom'] = geom
|
|
elif geom:
|
|
# The geometry is passed in as a parameter because we handled
|
|
# transformation conditions in this routine.
|
|
s['select_params'] = [backend.Adapter(geom)]
|
|
return self._spatial_attribute(func, s, **kwargs)
|
|
|
|
def _geom_attribute(self, func, tolerance=0.05, **kwargs):
|
|
"""
|
|
DRY routine for setting up a GeoQuerySet method that attaches a
|
|
Geometry attribute (e.g., `centroid`, `point_on_surface`).
|
|
"""
|
|
s = {'select_field' : GeomField(),}
|
|
if connections[self.db].ops.oracle:
|
|
s['procedure_fmt'] = '%(geo_col)s,%(tolerance)s'
|
|
s['procedure_args'] = {'tolerance' : tolerance}
|
|
return self._spatial_attribute(func, s, **kwargs)
|
|
|
|
def _geomset_attribute(self, func, geom, tolerance=0.05, **kwargs):
|
|
"""
|
|
DRY routine for setting up a GeoQuerySet method that attaches a
|
|
Geometry attribute and takes a Geoemtry parameter. This is used
|
|
for geometry set-like operations (e.g., intersection, difference,
|
|
union, sym_difference).
|
|
"""
|
|
s = {'geom_args' : ('geom',),
|
|
'select_field' : GeomField(),
|
|
'procedure_fmt' : '%(geo_col)s,%(geom)s',
|
|
'procedure_args' : {'geom' : geom},
|
|
}
|
|
if connections[self.db].ops.oracle:
|
|
s['procedure_fmt'] += ',%(tolerance)s'
|
|
s['procedure_args']['tolerance'] = tolerance
|
|
return self._spatial_attribute(func, s, **kwargs)
|
|
|
|
def _geocol_select(self, geo_field, field_name):
|
|
"""
|
|
Helper routine for constructing the SQL to select the geographic
|
|
column. Takes into account if the geographic field is in a
|
|
ForeignKey relation to the current model.
|
|
"""
|
|
opts = self.model._meta
|
|
if not geo_field in opts.fields:
|
|
# Is this operation going to be on a related geographic field?
|
|
# If so, it'll have to be added to the select related information
|
|
# (e.g., if 'location__point' was given as the field name).
|
|
self.query.add_select_related([field_name])
|
|
compiler = self.query.get_compiler(self.db)
|
|
compiler.pre_sql_setup()
|
|
rel_table, rel_col = self.query.related_select_cols[self.query.related_select_fields.index(geo_field)]
|
|
return compiler._field_column(geo_field, rel_table)
|
|
elif not geo_field in opts.local_fields:
|
|
# This geographic field is inherited from another model, so we have to
|
|
# use the db table for the _parent_ model instead.
|
|
tmp_fld, parent_model, direct, m2m = opts.get_field_by_name(geo_field.name)
|
|
return self.query.get_compiler(self.db)._field_column(geo_field, parent_model._meta.db_table)
|
|
else:
|
|
return self.query.get_compiler(self.db)._field_column(geo_field)
|
|
|
|
class GeoValuesQuerySet(ValuesQuerySet):
|
|
def __init__(self, *args, **kwargs):
|
|
super(GeoValuesQuerySet, self).__init__(*args, **kwargs)
|
|
# This flag tells `resolve_columns` to run the values through
|
|
# `convert_values`. This ensures that Geometry objects instead
|
|
# of string values are returned with `values()` or `values_list()`.
|
|
self.query.geo_values = True
|
|
|
|
class GeoValuesListQuerySet(GeoValuesQuerySet, ValuesListQuerySet):
|
|
pass
|