added all server files

author: ttt 2017-05-13 00:29:47 +0530
committer: ttt 2017-05-13 00:29:47 +0530
commit: 4336f5f06f61de30ae3fa54650fce63a9d5ef5be (patch)
tree: 23b4ee9b8e8f24bf732acf2f7ad22ed50cdd5670 /lib/python2.7/site-packages/django/contrib/gis/db/models
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12 files changed, 1905 insertions, 0 deletions
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/__init__.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/__init__.py
new file mode 100644
index 0000000..e36aa36
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/__init__.py
@@ -0,0 +1,14 @@
+# Want to get everything from the 'normal' models package.
+from django.db.models import *
+
+# Geographic aggregate functions
+from django.contrib.gis.db.models.aggregates import *
+
+# The GeoManager
+from django.contrib.gis.db.models.manager import GeoManager
+
+# The geographic-enabled fields.
+from django.contrib.gis.db.models.fields import (
+     GeometryField, PointField, LineStringField, PolygonField,
+     MultiPointField, MultiLineStringField, MultiPolygonField,
+     GeometryCollectionField)
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/aggregates.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/aggregates.py
new file mode 100644
index 0000000..d0fc6d3
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/aggregates.py
@@ -0,0 +1,16 @@
+from django.db.models import Aggregate
+
+class Collect(Aggregate):
+    name = 'Collect'
+
+class Extent(Aggregate):
+    name = 'Extent'
+
+class Extent3D(Aggregate):
+    name = 'Extent3D'
+
+class MakeLine(Aggregate):
+    name = 'MakeLine'
+
+class Union(Aggregate):
+    name = 'Union'
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/fields.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/fields.py
new file mode 100644
index 0000000..2e221b7
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/fields.py
@@ -0,0 +1,305 @@
+from django.db.models.fields import Field
+from django.db.models.sql.expressions import SQLEvaluator
+from django.utils.translation import ugettext_lazy as _
+from django.contrib.gis import forms
+from django.contrib.gis.db.models.proxy import GeometryProxy
+from django.contrib.gis.geometry.backend import Geometry, GeometryException
+from django.utils import six
+
+# Local cache of the spatial_ref_sys table, which holds SRID data for each
+# spatial database alias. This cache exists so that the database isn't queried
+# for SRID info each time a distance query is constructed.
+_srid_cache = {}
+
+def get_srid_info(srid, connection):
+    """
+    Returns the units, unit name, and spheroid WKT associated with the
+    given SRID from the `spatial_ref_sys` (or equivalent) spatial database
+    table for the given database connection.  These results are cached.
+    """
+    global _srid_cache
+
+    try:
+        # The SpatialRefSys model for the spatial backend.
+        SpatialRefSys = connection.ops.spatial_ref_sys()
+    except NotImplementedError:
+        # No `spatial_ref_sys` table in spatial backend (e.g., MySQL).
+        return None, None, None
+
+    if not connection.alias in _srid_cache:
+        # Initialize SRID dictionary for database if it doesn't exist.
+        _srid_cache[connection.alias] = {}
+
+    if not srid in _srid_cache[connection.alias]:
+        # Use `SpatialRefSys` model to query for spatial reference info.
+        sr = SpatialRefSys.objects.using(connection.alias).get(srid=srid)
+        units, units_name = sr.units
+        spheroid = SpatialRefSys.get_spheroid(sr.wkt)
+        _srid_cache[connection.alias][srid] = (units, units_name, spheroid)
+
+    return _srid_cache[connection.alias][srid]
+
+class GeometryField(Field):
+    "The base GIS field -- maps to the OpenGIS Specification Geometry type."
+
+    # The OpenGIS Geometry name.
+    geom_type = 'GEOMETRY'
+    form_class = forms.GeometryField
+
+    # Geodetic units.
+    geodetic_units = ('Decimal Degree', 'degree')
+
+    description = _("The base GIS field -- maps to the OpenGIS Specification Geometry type.")
+
+    def __init__(self, verbose_name=None, srid=4326, spatial_index=True, dim=2,
+                 geography=False, **kwargs):
+        """
+        The initialization function for geometry fields.  Takes the following
+        as keyword arguments:
+
+        srid:
+         The spatial reference system identifier, an OGC standard.
+         Defaults to 4326 (WGS84).
+
+        spatial_index:
+         Indicates whether to create a spatial index.  Defaults to True.
+         Set this instead of 'db_index' for geographic fields since index
+         creation is different for geometry columns.
+
+        dim:
+         The number of dimensions for this geometry.  Defaults to 2.
+
+        extent:
+         Customize the extent, in a 4-tuple of WGS 84 coordinates, for the
+         geometry field entry in the `USER_SDO_GEOM_METADATA` table.  Defaults
+         to (-180.0, -90.0, 180.0, 90.0).
+
+        tolerance:
+         Define the tolerance, in meters, to use for the geometry field
+         entry in the `USER_SDO_GEOM_METADATA` table.  Defaults to 0.05.
+        """
+
+        # Setting the index flag with the value of the `spatial_index` keyword.
+        self.spatial_index = spatial_index
+
+        # Setting the SRID and getting the units.  Unit information must be
+        # easily available in the field instance for distance queries.
+        self.srid = srid
+
+        # Setting the dimension of the geometry field.
+        self.dim = dim
+
+        # Setting the verbose_name keyword argument with the positional
+        # first parameter, so this works like normal fields.
+        kwargs['verbose_name'] = verbose_name
+
+        # Is this a geography rather than a geometry column?
+        self.geography = geography
+
+        # Oracle-specific private attributes for creating the entry in
+        # `USER_SDO_GEOM_METADATA`
+        self._extent = kwargs.pop('extent', (-180.0, -90.0, 180.0, 90.0))
+        self._tolerance = kwargs.pop('tolerance', 0.05)
+
+        super(GeometryField, self).__init__(**kwargs)
+
+    # The following functions are used to get the units, their name, and
+    # the spheroid corresponding to the SRID of the GeometryField.
+    def _get_srid_info(self, connection):
+        # Get attributes from `get_srid_info`.
+        self._units, self._units_name, self._spheroid = get_srid_info(self.srid, connection)
+
+    def spheroid(self, connection):
+        if not hasattr(self, '_spheroid'):
+            self._get_srid_info(connection)
+        return self._spheroid
+
+    def units(self, connection):
+        if not hasattr(self, '_units'):
+            self._get_srid_info(connection)
+        return self._units
+
+    def units_name(self, connection):
+        if not hasattr(self, '_units_name'):
+            self._get_srid_info(connection)
+        return self._units_name
+
+    ### Routines specific to GeometryField ###
+    def geodetic(self, connection):
+        """
+        Returns true if this field's SRID corresponds with a coordinate
+        system that uses non-projected units (e.g., latitude/longitude).
+        """
+        return self.units_name(connection) in self.geodetic_units
+
+    def get_distance(self, value, lookup_type, connection):
+        """
+        Returns a distance number in units of the field.  For example, if
+        `D(km=1)` was passed in and the units of the field were in meters,
+        then 1000 would be returned.
+        """
+        return connection.ops.get_distance(self, value, lookup_type)
+
+    def get_prep_value(self, value):
+        """
+        Spatial lookup values are either a parameter that is (or may be
+        converted to) a geometry, or a sequence of lookup values that
+        begins with a geometry.  This routine will setup the geometry
+        value properly, and preserve any other lookup parameters before
+        returning to the caller.
+        """
+        if isinstance(value, SQLEvaluator):
+            return value
+        elif isinstance(value, (tuple, list)):
+            geom = value[0]
+            seq_value = True
+        else:
+            geom = value
+            seq_value = False
+
+        # When the input is not a GEOS geometry, attempt to construct one
+        # from the given string input.
+        if isinstance(geom, Geometry):
+            pass
+        elif isinstance(geom, (bytes, six.string_types)) or hasattr(geom, '__geo_interface__'):
+            try:
+                geom = Geometry(geom)
+            except GeometryException:
+                raise ValueError('Could not create geometry from lookup value.')
+        else:
+            raise ValueError('Cannot use object with type %s for a geometry lookup parameter.' % type(geom).__name__)
+
+        # Assigning the SRID value.
+        geom.srid = self.get_srid(geom)
+
+        if seq_value:
+            lookup_val = [geom]
+            lookup_val.extend(value[1:])
+            return tuple(lookup_val)
+        else:
+            return geom
+
+    def get_srid(self, geom):
+        """
+        Returns the default SRID for the given geometry, taking into account
+        the SRID set for the field.  For example, if the input geometry
+        has no SRID, then that of the field will be returned.
+        """
+        gsrid = geom.srid # SRID of given geometry.
+        if gsrid is None or self.srid == -1 or (gsrid == -1 and self.srid != -1):
+            return self.srid
+        else:
+            return gsrid
+
+    ### Routines overloaded from Field ###
+    def contribute_to_class(self, cls, name):
+        super(GeometryField, self).contribute_to_class(cls, name)
+
+        # Setup for lazy-instantiated Geometry object.
+        setattr(cls, self.attname, GeometryProxy(Geometry, self))
+
+    def db_type(self, connection):
+        return connection.ops.geo_db_type(self)
+
+    def formfield(self, **kwargs):
+        defaults = {'form_class' : self.form_class,
+                    'geom_type' : self.geom_type,
+                    'srid' : self.srid,
+                    }
+        defaults.update(kwargs)
+        if (self.dim > 2 and not 'widget' in kwargs and
+                not getattr(defaults['form_class'].widget, 'supports_3d', False)):
+            defaults['widget'] = forms.Textarea
+        return super(GeometryField, self).formfield(**defaults)
+
+    def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False):
+        """
+        Prepare for the database lookup, and return any spatial parameters
+        necessary for the query.  This includes wrapping any geometry
+        parameters with a backend-specific adapter and formatting any distance
+        parameters into the correct units for the coordinate system of the
+        field.
+        """
+        if lookup_type in connection.ops.gis_terms:
+            # special case for isnull lookup
+            if lookup_type == 'isnull':
+                return []
+
+            # Populating the parameters list, and wrapping the Geometry
+            # with the Adapter of the spatial backend.
+            if isinstance(value, (tuple, list)):
+                params = [connection.ops.Adapter(value[0])]
+                if lookup_type in connection.ops.distance_functions:
+                    # Getting the distance parameter in the units of the field.
+                    params += self.get_distance(value[1:], lookup_type, connection)
+                elif lookup_type in connection.ops.truncate_params:
+                    # Lookup is one where SQL parameters aren't needed from the
+                    # given lookup value.
+                    pass
+                else:
+                    params += value[1:]
+            elif isinstance(value, SQLEvaluator):
+                params = []
+            else:
+                params = [connection.ops.Adapter(value)]
+
+            return params
+        else:
+            raise ValueError('%s is not a valid spatial lookup for %s.' %
+                             (lookup_type, self.__class__.__name__))
+
+    def get_prep_lookup(self, lookup_type, value):
+        if lookup_type == 'isnull':
+            return bool(value)
+        else:
+            return self.get_prep_value(value)
+
+    def get_db_prep_save(self, value, connection):
+        "Prepares the value for saving in the database."
+        if value is None:
+            return None
+        else:
+            return connection.ops.Adapter(self.get_prep_value(value))
+
+    def get_placeholder(self, value, connection):
+        """
+        Returns the placeholder for the geometry column for the
+        given value.
+        """
+        return connection.ops.get_geom_placeholder(self, value)
+
+# The OpenGIS Geometry Type Fields
+class PointField(GeometryField):
+    geom_type = 'POINT'
+    form_class = forms.PointField
+    description = _("Point")
+
+class LineStringField(GeometryField):
+    geom_type = 'LINESTRING'
+    form_class = forms.LineStringField
+    description = _("Line string")
+
+class PolygonField(GeometryField):
+    geom_type = 'POLYGON'
+    form_class = forms.PolygonField
+    description = _("Polygon")
+
+class MultiPointField(GeometryField):
+    geom_type = 'MULTIPOINT'
+    form_class = forms.MultiPointField
+    description = _("Multi-point")
+
+class MultiLineStringField(GeometryField):
+    geom_type = 'MULTILINESTRING'
+    form_class = forms.MultiLineStringField
+    description = _("Multi-line string")
+
+class MultiPolygonField(GeometryField):
+    geom_type = 'MULTIPOLYGON'
+    form_class = forms.MultiPolygonField
+    description = _("Multi polygon")
+
+class GeometryCollectionField(GeometryField):
+    geom_type = 'GEOMETRYCOLLECTION'
+    form_class = forms.GeometryCollectionField
+    description = _("Geometry collection")
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/manager.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/manager.py
new file mode 100644
index 0000000..aa57e3a
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/manager.py
@@ -0,0 +1,103 @@
+from django.db.models.manager import Manager
+from django.contrib.gis.db.models.query import GeoQuerySet
+
+class GeoManager(Manager):
+    "Overrides Manager to return Geographic QuerySets."
+
+    # This manager should be used for queries on related fields
+    # so that geometry columns on Oracle and MySQL are selected
+    # properly.
+    use_for_related_fields = True
+
+    def get_queryset(self):
+        return GeoQuerySet(self.model, using=self._db)
+
+    def area(self, *args, **kwargs):
+        return self.get_queryset().area(*args, **kwargs)
+
+    def centroid(self, *args, **kwargs):
+        return self.get_queryset().centroid(*args, **kwargs)
+
+    def collect(self, *args, **kwargs):
+        return self.get_queryset().collect(*args, **kwargs)
+
+    def difference(self, *args, **kwargs):
+        return self.get_queryset().difference(*args, **kwargs)
+
+    def distance(self, *args, **kwargs):
+        return self.get_queryset().distance(*args, **kwargs)
+
+    def envelope(self, *args, **kwargs):
+        return self.get_queryset().envelope(*args, **kwargs)
+
+    def extent(self, *args, **kwargs):
+        return self.get_queryset().extent(*args, **kwargs)
+
+    def extent3d(self, *args, **kwargs):
+        return self.get_queryset().extent3d(*args, **kwargs)
+
+    def force_rhr(self, *args, **kwargs):
+        return self.get_queryset().force_rhr(*args, **kwargs)
+
+    def geohash(self, *args, **kwargs):
+        return self.get_queryset().geohash(*args, **kwargs)
+
+    def geojson(self, *args, **kwargs):
+        return self.get_queryset().geojson(*args, **kwargs)
+
+    def gml(self, *args, **kwargs):
+        return self.get_queryset().gml(*args, **kwargs)
+
+    def intersection(self, *args, **kwargs):
+        return self.get_queryset().intersection(*args, **kwargs)
+
+    def kml(self, *args, **kwargs):
+        return self.get_queryset().kml(*args, **kwargs)
+
+    def length(self, *args, **kwargs):
+        return self.get_queryset().length(*args, **kwargs)
+
+    def make_line(self, *args, **kwargs):
+        return self.get_queryset().make_line(*args, **kwargs)
+
+    def mem_size(self, *args, **kwargs):
+        return self.get_queryset().mem_size(*args, **kwargs)
+
+    def num_geom(self, *args, **kwargs):
+        return self.get_queryset().num_geom(*args, **kwargs)
+
+    def num_points(self, *args, **kwargs):
+        return self.get_queryset().num_points(*args, **kwargs)
+
+    def perimeter(self, *args, **kwargs):
+        return self.get_queryset().perimeter(*args, **kwargs)
+
+    def point_on_surface(self, *args, **kwargs):
+        return self.get_queryset().point_on_surface(*args, **kwargs)
+
+    def reverse_geom(self, *args, **kwargs):
+        return self.get_queryset().reverse_geom(*args, **kwargs)
+
+    def scale(self, *args, **kwargs):
+        return self.get_queryset().scale(*args, **kwargs)
+
+    def snap_to_grid(self, *args, **kwargs):
+        return self.get_queryset().snap_to_grid(*args, **kwargs)
+
+    def svg(self, *args, **kwargs):
+        return self.get_queryset().svg(*args, **kwargs)
+
+    def sym_difference(self, *args, **kwargs):
+        return self.get_queryset().sym_difference(*args, **kwargs)
+
+    def transform(self, *args, **kwargs):
+        return self.get_queryset().transform(*args, **kwargs)
+
+    def translate(self, *args, **kwargs):
+        return self.get_queryset().translate(*args, **kwargs)
+
+    def union(self, *args, **kwargs):
+        return self.get_queryset().union(*args, **kwargs)
+
+    def unionagg(self, *args, **kwargs):
+        return self.get_queryset().unionagg(*args, **kwargs)
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/proxy.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/proxy.py
new file mode 100644
index 0000000..1fdc503
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/proxy.py
@@ -0,0 +1,66 @@
+"""
+The GeometryProxy object, allows for lazy-geometries.  The proxy uses
+Python descriptors for instantiating and setting Geometry objects
+corresponding to geographic model fields.
+
+Thanks to Robert Coup for providing this functionality (see #4322).
+"""
+from django.contrib.gis import memoryview
+from django.utils import six
+
+class GeometryProxy(object):
+    def __init__(self, klass, field):
+        """
+        Proxy initializes on the given Geometry class (not an instance) and
+        the GeometryField.
+        """
+        self._field = field
+        self._klass = klass
+
+    def __get__(self, obj, type=None):
+        """
+        This accessor retrieves the geometry, initializing it using the geometry
+        class specified during initialization and the HEXEWKB value of the field.
+        Currently, only GEOS or OGR geometries are supported.
+        """
+        if obj is None:
+            # Accessed on a class, not an instance
+            return self
+
+        # Getting the value of the field.
+        geom_value = obj.__dict__[self._field.attname]
+
+        if isinstance(geom_value, self._klass):
+            geom = geom_value
+        elif (geom_value is None) or (geom_value==''):
+            geom = None
+        else:
+            # Otherwise, a Geometry object is built using the field's contents,
+            # and the model's corresponding attribute is set.
+            geom = self._klass(geom_value)
+            setattr(obj, self._field.attname, geom)
+        return geom
+
+    def __set__(self, obj, value):
+        """
+        This accessor sets the proxied geometry with the geometry class
+        specified during initialization.  Values of None, HEXEWKB, or WKT may
+        be used to set the geometry as well.
+        """
+        # The OGC Geometry type of the field.
+        gtype = self._field.geom_type
+
+        # The geometry type must match that of the field -- unless the
+        # general GeometryField is used.
+        if isinstance(value, self._klass) and (str(value.geom_type).upper() == gtype or gtype == 'GEOMETRY'):
+            # Assigning the SRID to the geometry.
+            if value.srid is None: value.srid = self._field.srid
+        elif value is None or isinstance(value, six.string_types + (memoryview,)):
+            # Set with None, WKT, HEX, or WKB
+            pass
+        else:
+            raise TypeError('cannot set %s GeometryProxy with value of type: %s' % (obj.__class__.__name__, type(value)))
+
+        # Setting the objects dictionary with the value, and returning.
+        obj.__dict__[self._field.attname] = value
+        return value
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/query.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/query.py
new file mode 100644
index 0000000..c89912b
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/query.py
@@ -0,0 +1,784 @@
+from django.db import connections
+from django.db.models.query import QuerySet, ValuesQuerySet, ValuesListQuerySet
+
+from django.contrib.gis import memoryview
+from django.contrib.gis.db.models import aggregates
+from django.contrib.gis.db.models.fields import get_srid_info, PointField, LineStringField
+from django.contrib.gis.db.models.sql import AreaField, DistanceField, GeomField, GeoQuery
+from django.contrib.gis.geometry.backend import Geometry
+from django.contrib.gis.measure import Area, Distance
+
+from django.utils import six
+
+
+class GeoQuerySet(QuerySet):
+    "The Geographic QuerySet."
+
+    ### Methods overloaded from QuerySet ###
+    def __init__(self, model=None, query=None, using=None):
+        super(GeoQuerySet, self).__init__(model=model, query=query, using=using)
+        self.query = query or GeoQuery(self.model)
+
+    def values(self, *fields):
+        return self._clone(klass=GeoValuesQuerySet, setup=True, _fields=fields)
+
+    def values_list(self, *fields, **kwargs):
+        flat = kwargs.pop('flat', False)
+        if kwargs:
+            raise TypeError('Unexpected keyword arguments to values_list: %s'
+                    % (list(kwargs),))
+        if flat and len(fields) > 1:
+            raise TypeError("'flat' is not valid when values_list is called with more than one field.")
+        return self._clone(klass=GeoValuesListQuerySet, setup=True, flat=flat,
+                           _fields=fields)
+
+    ### GeoQuerySet Methods ###
+    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)
+
+    def centroid(self, **kwargs):
+        """
+        Returns the centroid of the geographic field in a `centroid`
+        attribute on each element of this GeoQuerySet.
+        """
+        return self._geom_attribute('centroid', **kwargs)
+
+    def collect(self, **kwargs):
+        """
+        Performs an aggregate collect operation on the given geometry field.
+        This is analagous to a union operation, but much faster because
+        boundaries are not dissolved.
+        """
+        return self._spatial_aggregate(aggregates.Collect, **kwargs)
+
+    def difference(self, geom, **kwargs):
+        """
+        Returns the spatial difference of the geographic field in a `difference`
+        attribute on each element of this GeoQuerySet.
+        """
+        return self._geomset_attribute('difference', geom, **kwargs)
+
+    def distance(self, geom, **kwargs):
+        """
+        Returns the distance from the given geographic field name to the
+        given geometry in a `distance` attribute on each element of the
+        GeoQuerySet.
+
+        Keyword Arguments:
+         `spheroid`  => If the geometry field is geodetic and PostGIS is
+                        the spatial database, then the more accurate
+                        spheroid calculation will be used instead of the
+                        quicker sphere calculation.
+
+         `tolerance` => Used only for Oracle. The tolerance is
+                        in meters -- a default of 5 centimeters (0.05)
+                        is used.
+        """
+        return self._distance_attribute('distance', geom, **kwargs)
+
+    def envelope(self, **kwargs):
+        """
+        Returns a Geometry representing the bounding box of the
+        Geometry field in an `envelope` attribute on each element of
+        the GeoQuerySet.
+        """
+        return self._geom_attribute('envelope', **kwargs)
+
+    def extent(self, **kwargs):
+        """
+        Returns the extent (aggregate) of the features in the GeoQuerySet.  The
+        extent will be returned as a 4-tuple, consisting of (xmin, ymin, xmax, ymax).
+        """
+        return self._spatial_aggregate(aggregates.Extent, **kwargs)
+
+    def extent3d(self, **kwargs):
+        """
+        Returns the aggregate extent, in 3D, of the features in the
+        GeoQuerySet. It is returned as a 6-tuple, comprising:
+          (xmin, ymin, zmin, xmax, ymax, zmax).
+        """
+        return self._spatial_aggregate(aggregates.Extent3D, **kwargs)
+
+    def force_rhr(self, **kwargs):
+        """
+        Returns a modified version of the Polygon/MultiPolygon in which
+        all of the vertices follow the Right-Hand-Rule.  By default,
+        this is attached as the `force_rhr` attribute on each element
+        of the GeoQuerySet.
+        """
+        return self._geom_attribute('force_rhr', **kwargs)
+
+    def geojson(self, precision=8, crs=False, bbox=False, **kwargs):
+        """
+        Returns a GeoJSON representation of the geomtry field in a `geojson`
+        attribute on each element of the GeoQuerySet.
+
+        The `crs` and `bbox` keywords may be set to True if the users wants
+        the coordinate reference system and the bounding box to be included
+        in the GeoJSON representation of the geometry.
+        """
+        backend = connections[self.db].ops
+        if not backend.geojson:
+            raise NotImplementedError('Only PostGIS 1.3.4+ and SpatiaLite 3.0+ '
+                                      'support GeoJSON serialization.')
+
+        if not isinstance(precision, six.integer_types):
+            raise TypeError('Precision keyword must be set with an integer.')
+
+        # Setting the options flag -- which depends on which version of
+        # PostGIS we're using. SpatiaLite only uses the first group of options.
+        if backend.spatial_version >= (1, 4, 0):
+            options = 0
+            if crs and bbox: options = 3
+            elif bbox: options = 1
+            elif crs: options = 2
+        else:
+            options = 0
+            if crs and bbox: options = 3
+            elif crs: options = 1
+            elif bbox: options = 2
+        s = {'desc' : 'GeoJSON',
+             'procedure_args' : {'precision' : precision, 'options' : options},
+             'procedure_fmt' : '%(geo_col)s,%(precision)s,%(options)s',
+             }
+        return self._spatial_attribute('geojson', s, **kwargs)
+
+    def geohash(self, precision=20, **kwargs):
+        """
+        Returns a GeoHash representation of the given field in a `geohash`
+        attribute on each element of the GeoQuerySet.
+
+        The `precision` keyword may be used to custom the number of
+        _characters_ used in the output GeoHash, the default is 20.
+        """
+        s = {'desc' : 'GeoHash',
+             'procedure_args': {'precision': precision},
+             'procedure_fmt': '%(geo_col)s,%(precision)s',
+             }
+        return self._spatial_attribute('geohash', s, **kwargs)
+
+    def gml(self, precision=8, version=2, **kwargs):
+        """
+        Returns GML representation of the given field in a `gml` attribute
+        on each element of the GeoQuerySet.
+        """
+        backend = connections[self.db].ops
+        s = {'desc' : 'GML', 'procedure_args' : {'precision' : precision}}
+        if backend.postgis:
+            # PostGIS AsGML() aggregate function parameter order depends on the
+            # version -- uggh.
+            if backend.spatial_version > (1, 3, 1):
+                s['procedure_fmt'] = '%(version)s,%(geo_col)s,%(precision)s'
+            else:
+                s['procedure_fmt'] = '%(geo_col)s,%(precision)s,%(version)s'
+            s['procedure_args'] = {'precision' : precision, 'version' : version}
+
+        return self._spatial_attribute('gml', s, **kwargs)
+
+    def intersection(self, geom, **kwargs):
+        """
+        Returns the spatial intersection of the Geometry field in
+        an `intersection` attribute on each element of this
+        GeoQuerySet.
+        """
+        return self._geomset_attribute('intersection', geom, **kwargs)
+
+    def kml(self, **kwargs):
+        """
+        Returns KML representation of the geometry field in a `kml`
+        attribute on each element of this GeoQuerySet.
+        """
+        s = {'desc' : 'KML',
+             'procedure_fmt' : '%(geo_col)s,%(precision)s',
+             'procedure_args' : {'precision' : kwargs.pop('precision', 8)},
+             }
+        return self._spatial_attribute('kml', s, **kwargs)
+
+    def length(self, **kwargs):
+        """
+        Returns the length of the geometry field as a `Distance` object
+        stored in a `length` attribute on each element of this GeoQuerySet.
+        """
+        return self._distance_attribute('length', None, **kwargs)
+
+    def make_line(self, **kwargs):
+        """
+        Creates a linestring from all of the PointField geometries in the
+        this GeoQuerySet and returns it.  This is a spatial aggregate
+        method, and thus returns a geometry rather than a GeoQuerySet.
+        """
+        return self._spatial_aggregate(aggregates.MakeLine, geo_field_type=PointField, **kwargs)
+
+    def mem_size(self, **kwargs):
+        """
+        Returns the memory size (number of bytes) that the geometry field takes
+        in a `mem_size` attribute  on each element of this GeoQuerySet.
+        """
+        return self._spatial_attribute('mem_size', {}, **kwargs)
+
+    def num_geom(self, **kwargs):
+        """
+        Returns the number of geometries if the field is a
+        GeometryCollection or Multi* Field in a `num_geom`
+        attribute on each element of this GeoQuerySet; otherwise
+        the sets with None.
+        """
+        return self._spatial_attribute('num_geom', {}, **kwargs)
+
+    def num_points(self, **kwargs):
+        """
+        Returns the number of points in the first linestring in the
+        Geometry field in a `num_points` attribute on each element of
+        this GeoQuerySet; otherwise sets with None.
+        """
+        return self._spatial_attribute('num_points', {}, **kwargs)
+
+    def perimeter(self, **kwargs):
+        """
+        Returns the perimeter of the geometry field as a `Distance` object
+        stored in a `perimeter` attribute on each element of this GeoQuerySet.
+        """
+        return self._distance_attribute('perimeter', None, **kwargs)
+
+    def point_on_surface(self, **kwargs):
+        """
+        Returns a Point geometry guaranteed to lie on the surface of the
+        Geometry field in a `point_on_surface` attribute on each element
+        of this GeoQuerySet; otherwise sets with None.
+        """
+        return self._geom_attribute('point_on_surface', **kwargs)
+
+    def reverse_geom(self, **kwargs):
+        """
+        Reverses the coordinate order of the geometry, and attaches as a
+        `reverse` attribute on each element of this GeoQuerySet.
+        """
+        s = {'select_field' : GeomField(),}
+        kwargs.setdefault('model_att', 'reverse_geom')
+        if connections[self.db].ops.oracle:
+            s['geo_field_type'] = LineStringField
+        return self._spatial_attribute('reverse', s, **kwargs)
+
+    def scale(self, x, y, z=0.0, **kwargs):
+        """
+        Scales the geometry to a new size by multiplying the ordinates
+        with the given x,y,z scale factors.
+        """
+        if connections[self.db].ops.spatialite:
+            if z != 0.0:
+                raise NotImplementedError('SpatiaLite does not support 3D scaling.')
+            s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s',
+                 'procedure_args' : {'x' : x, 'y' : y},
+                 'select_field' : GeomField(),
+                 }
+        else:
+            s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s,%(z)s',
+                 'procedure_args' : {'x' : x, 'y' : y, 'z' : z},
+                 'select_field' : GeomField(),
+                 }
+        return self._spatial_attribute('scale', s, **kwargs)
+
+    def snap_to_grid(self, *args, **kwargs):
+        """
+        Snap all points of the input geometry to the grid.  How the
+        geometry is snapped to the grid depends on how many arguments
+        were given:
+          - 1 argument : A single size to snap both the X and Y grids to.
+          - 2 arguments: X and Y sizes to snap the grid to.
+          - 4 arguments: X, Y sizes and the X, Y origins.
+        """
+        if False in [isinstance(arg, (float,) + six.integer_types) for arg in args]:
+            raise TypeError('Size argument(s) for the grid must be a float or integer values.')
+
+        nargs = len(args)
+        if nargs == 1:
+            size = args[0]
+            procedure_fmt = '%(geo_col)s,%(size)s'
+            procedure_args = {'size' : size}
+        elif nargs == 2:
+            xsize, ysize = args
+            procedure_fmt = '%(geo_col)s,%(xsize)s,%(ysize)s'
+            procedure_args = {'xsize' : xsize, 'ysize' : ysize}
+        elif nargs == 4:
+            xsize, ysize, xorigin, yorigin = args
+            procedure_fmt = '%(geo_col)s,%(xorigin)s,%(yorigin)s,%(xsize)s,%(ysize)s'
+            procedure_args = {'xsize' : xsize, 'ysize' : ysize,
+                              'xorigin' : xorigin, 'yorigin' : yorigin}
+        else:
+            raise ValueError('Must provide 1, 2, or 4 arguments to `snap_to_grid`.')
+
+        s = {'procedure_fmt' : procedure_fmt,
+             'procedure_args' : procedure_args,
+             'select_field' : GeomField(),
+             }
+
+        return self._spatial_attribute('snap_to_grid', s, **kwargs)
+
+    def svg(self, relative=False, precision=8, **kwargs):
+        """
+        Returns SVG representation of the geographic field in a `svg`
+        attribute on each element of this GeoQuerySet.
+
+        Keyword Arguments:
+         `relative`  => If set to True, this will evaluate the path in
+                        terms of relative moves (rather than absolute).
+
+         `precision` => May be used to set the maximum number of decimal
+                        digits used in output (defaults to 8).
+        """
+        relative = int(bool(relative))
+        if not isinstance(precision, six.integer_types):
+            raise TypeError('SVG precision keyword argument must be an integer.')
+        s = {'desc' : 'SVG',
+             'procedure_fmt' : '%(geo_col)s,%(rel)s,%(precision)s',
+             'procedure_args' : {'rel' : relative,
+                                 'precision' : precision,
+                                 }
+             }
+        return self._spatial_attribute('svg', s, **kwargs)
+
+    def sym_difference(self, geom, **kwargs):
+        """
+        Returns the symmetric difference of the geographic field in a
+        `sym_difference` attribute on each element of this GeoQuerySet.
+        """
+        return self._geomset_attribute('sym_difference', geom, **kwargs)
+
+    def translate(self, x, y, z=0.0, **kwargs):
+        """
+        Translates the geometry to a new location using the given numeric
+        parameters as offsets.
+        """
+        if connections[self.db].ops.spatialite:
+            if z != 0.0:
+                raise NotImplementedError('SpatiaLite does not support 3D translation.')
+            s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s',
+                 'procedure_args' : {'x' : x, 'y' : y},
+                 'select_field' : GeomField(),
+                 }
+        else:
+            s = {'procedure_fmt' : '%(geo_col)s,%(x)s,%(y)s,%(z)s',
+                 'procedure_args' : {'x' : x, 'y' : y, 'z' : z},
+                 'select_field' : GeomField(),
+                 }
+        return self._spatial_attribute('translate', s, **kwargs)
+
+    def transform(self, srid=4326, **kwargs):
+        """
+        Transforms the given geometry field to the given SRID.  If no SRID is
+        provided, the transformation will default to using 4326 (WGS84).
+        """
+        if not isinstance(srid, six.integer_types):
+            raise TypeError('An integer SRID must be provided.')
+        field_name = kwargs.get('field_name', None)
+        tmp, geo_field = self._spatial_setup('transform', field_name=field_name)
+
+        # Getting the selection SQL for the given geographic field.
+        field_col = self._geocol_select(geo_field, field_name)
+
+        # Why cascading substitutions? Because spatial backends like
+        # Oracle and MySQL already require a function call to convert to text, thus
+        # when there's also a transformation we need to cascade the substitutions.
+        # For example, 'SDO_UTIL.TO_WKTGEOMETRY(SDO_CS.TRANSFORM( ... )'
+        geo_col = self.query.custom_select.get(geo_field, field_col)
+
+        # Setting the key for the field's column with the custom SELECT SQL to
+        # override the geometry column returned from the database.
+        custom_sel = '%s(%s, %s)' % (connections[self.db].ops.transform, geo_col, srid)
+        # TODO: Should we have this as an alias?
+        # custom_sel = '(%s(%s, %s)) AS %s' % (SpatialBackend.transform, geo_col, srid, qn(geo_field.name))
+        self.query.transformed_srid = srid # So other GeoQuerySet methods
+        self.query.custom_select[geo_field] = custom_sel
+        return self._clone()
+
+    def union(self, geom, **kwargs):
+        """
+        Returns the union of the geographic field with the given
+        Geometry in a `union` attribute on each element of this GeoQuerySet.
+        """
+        return self._geomset_attribute('union', geom, **kwargs)
+
+    def unionagg(self, **kwargs):
+        """
+        Performs an aggregate union on the given geometry field.  Returns
+        None if the GeoQuerySet is empty.  The `tolerance` keyword is for
+        Oracle backends only.
+        """
+        return self._spatial_aggregate(aggregates.Union, **kwargs)
+
+    ### Private API -- Abstracted DRY routines. ###
+    def _spatial_setup(self, att, desc=None, field_name=None, geo_field_type=None):
+        """
+        Performs set up for executing the spatial function.
+        """
+        # Does the spatial backend support this?
+        connection = connections[self.db]
+        func = getattr(connection.ops, att, False)
+        if desc is None: desc = att
+        if not func:
+            raise NotImplementedError('%s stored procedure not available on '
+                                      'the %s backend.' %
+                                      (desc, connection.ops.name))
+
+        # Initializing the procedure arguments.
+        procedure_args = {'function' : func}
+
+        # Is there a geographic field in the model to perform this
+        # operation on?
+        geo_field = self.query._geo_field(field_name)
+        if not geo_field:
+            raise TypeError('%s output only available on GeometryFields.' % func)
+
+        # If the `geo_field_type` keyword was used, then enforce that
+        # type limitation.
+        if not geo_field_type is None and not isinstance(geo_field, geo_field_type):
+            raise TypeError('"%s" stored procedures may only be called on %ss.' % (func, geo_field_type.__name__))
+
+        # Setting the procedure args.
+        procedure_args['geo_col'] = self._geocol_select(geo_field, field_name)
+
+        return procedure_args, geo_field
+
+    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()
+            for (rel_table, rel_col), field in self.query.related_select_cols:
+                if field == geo_field:
+                    return compiler._field_column(geo_field, rel_table)
+            raise ValueError("%r not in self.query.related_select_cols" % geo_field)
+        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
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/__init__.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/__init__.py
new file mode 100644
index 0000000..38d9507
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/__init__.py
@@ -0,0 +1,3 @@
+from django.contrib.gis.db.models.sql.conversion import AreaField, DistanceField, GeomField
+from django.contrib.gis.db.models.sql.query import GeoQuery
+from django.contrib.gis.db.models.sql.where import GeoWhereNode
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/aggregates.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/aggregates.py
new file mode 100644
index 0000000..ae848c0
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/aggregates.py
@@ -0,0 +1,62 @@
+from django.db.models.sql.aggregates import *
+from django.contrib.gis.db.models.fields import GeometryField
+
+class GeoAggregate(Aggregate):
+    # Default SQL template for spatial aggregates.
+    sql_template = '%(function)s(%(field)s)'
+
+    # Conversion class, if necessary.
+    conversion_class = None
+
+    # Flags for indicating the type of the aggregate.
+    is_extent = False
+
+    def __init__(self, col, source=None, is_summary=False, tolerance=0.05, **extra):
+        super(GeoAggregate, self).__init__(col, source, is_summary, **extra)
+
+        # Required by some Oracle aggregates.
+        self.tolerance = tolerance
+
+        # Can't use geographic aggregates on non-geometry fields.
+        if not isinstance(self.source, GeometryField):
+            raise ValueError('Geospatial aggregates only allowed on geometry fields.')
+
+    def as_sql(self, qn, connection):
+        "Return the aggregate, rendered as SQL with parameters."
+
+        if connection.ops.oracle:
+            self.extra['tolerance'] = self.tolerance
+
+        params = []
+
+        if hasattr(self.col, 'as_sql'):
+            field_name, params = self.col.as_sql(qn, connection)
+        elif isinstance(self.col, (list, tuple)):
+            field_name = '.'.join([qn(c) for c in self.col])
+        else:
+            field_name = self.col
+
+        sql_template, sql_function = connection.ops.spatial_aggregate_sql(self)
+
+        substitutions = {
+            'function': sql_function,
+            'field': field_name
+        }
+        substitutions.update(self.extra)
+
+        return sql_template % substitutions, params
+
+class Collect(GeoAggregate):
+    pass
+
+class Extent(GeoAggregate):
+    is_extent = '2D'
+
+class Extent3D(GeoAggregate):
+    is_extent = '3D'
+
+class MakeLine(GeoAggregate):
+    pass
+
+class Union(GeoAggregate):
+    pass
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/compiler.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/compiler.py
new file mode 100644
index 0000000..3fc9c17
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/compiler.py
@@ -0,0 +1,313 @@
+import datetime
+
+from django.conf import settings
+from django.db.backends.util import truncate_name, typecast_date, typecast_timestamp
+from django.db.models.sql import compiler
+from django.db.models.sql.constants import MULTI
+from django.utils import six
+from django.utils.six.moves import zip, zip_longest
+from django.utils import timezone
+
+SQLCompiler = compiler.SQLCompiler
+
+class GeoSQLCompiler(compiler.SQLCompiler):
+
+    def get_columns(self, with_aliases=False):
+        """
+        Return the list of columns to use in the select statement. If no
+        columns have been specified, returns all columns relating to fields in
+        the model.
+
+        If 'with_aliases' is true, any column names that are duplicated
+        (without the table names) are given unique aliases. This is needed in
+        some cases to avoid ambiguitity with nested queries.
+
+        This routine is overridden from Query to handle customized selection of
+        geometry columns.
+        """
+        qn = self.quote_name_unless_alias
+        qn2 = self.connection.ops.quote_name
+        result = ['(%s) AS %s' % (self.get_extra_select_format(alias) % col[0], qn2(alias))
+                  for alias, col in six.iteritems(self.query.extra_select)]
+        params = []
+        aliases = set(self.query.extra_select.keys())
+        if with_aliases:
+            col_aliases = aliases.copy()
+        else:
+            col_aliases = set()
+        if self.query.select:
+            only_load = self.deferred_to_columns()
+            # This loop customized for GeoQuery.
+            for col, field in self.query.select:
+                if isinstance(col, (list, tuple)):
+                    alias, column = col
+                    table = self.query.alias_map[alias].table_name
+                    if table in only_load and column not in only_load[table]:
+                        continue
+                    r = self.get_field_select(field, alias, column)
+                    if with_aliases:
+                        if col[1] in col_aliases:
+                            c_alias = 'Col%d' % len(col_aliases)
+                            result.append('%s AS %s' % (r, c_alias))
+                            aliases.add(c_alias)
+                            col_aliases.add(c_alias)
+                        else:
+                            result.append('%s AS %s' % (r, qn2(col[1])))
+                            aliases.add(r)
+                            col_aliases.add(col[1])
+                    else:
+                        result.append(r)
+                        aliases.add(r)
+                        col_aliases.add(col[1])
+                else:
+                    col_sql, col_params = col.as_sql(qn, self.connection)
+                    result.append(col_sql)
+                    params.extend(col_params)
+
+                    if hasattr(col, 'alias'):
+                        aliases.add(col.alias)
+                        col_aliases.add(col.alias)
+
+        elif self.query.default_cols:
+            cols, new_aliases = self.get_default_columns(with_aliases,
+                    col_aliases)
+            result.extend(cols)
+            aliases.update(new_aliases)
+
+        max_name_length = self.connection.ops.max_name_length()
+        for alias, aggregate in self.query.aggregate_select.items():
+            agg_sql, agg_params = aggregate.as_sql(qn, self.connection)
+            if alias is None:
+                result.append(agg_sql)
+            else:
+                result.append('%s AS %s' % (agg_sql, qn(truncate_name(alias, max_name_length))))
+            params.extend(agg_params)
+
+        # This loop customized for GeoQuery.
+        for (table, col), field in self.query.related_select_cols:
+            r = self.get_field_select(field, table, col)
+            if with_aliases and col in col_aliases:
+                c_alias = 'Col%d' % len(col_aliases)
+                result.append('%s AS %s' % (r, c_alias))
+                aliases.add(c_alias)
+                col_aliases.add(c_alias)
+            else:
+                result.append(r)
+                aliases.add(r)
+                col_aliases.add(col)
+
+        self._select_aliases = aliases
+        return result, params
+
+    def get_default_columns(self, with_aliases=False, col_aliases=None,
+            start_alias=None, opts=None, as_pairs=False, from_parent=None):
+        """
+        Computes the default columns for selecting every field in the base
+        model. Will sometimes be called to pull in related models (e.g. via
+        select_related), in which case "opts" and "start_alias" will be given
+        to provide a starting point for the traversal.
+
+        Returns a list of strings, quoted appropriately for use in SQL
+        directly, as well as a set of aliases used in the select statement (if
+        'as_pairs' is True, returns a list of (alias, col_name) pairs instead
+        of strings as the first component and None as the second component).
+
+        This routine is overridden from Query to handle customized selection of
+        geometry columns.
+        """
+        result = []
+        if opts is None:
+            opts = self.query.get_meta()
+        aliases = set()
+        only_load = self.deferred_to_columns()
+        seen = self.query.included_inherited_models.copy()
+        if start_alias:
+            seen[None] = start_alias
+        for field, model in opts.get_concrete_fields_with_model():
+            if from_parent and model is not None and issubclass(from_parent, model):
+                # Avoid loading data for already loaded parents.
+                continue
+            alias = self.query.join_parent_model(opts, model, start_alias, seen)
+            table = self.query.alias_map[alias].table_name
+            if table in only_load and field.column not in only_load[table]:
+                continue
+            if as_pairs:
+                result.append((alias, field))
+                aliases.add(alias)
+                continue
+            # This part of the function is customized for GeoQuery. We
+            # see if there was any custom selection specified in the
+            # dictionary, and set up the selection format appropriately.
+            field_sel = self.get_field_select(field, alias)
+            if with_aliases and field.column in col_aliases:
+                c_alias = 'Col%d' % len(col_aliases)
+                result.append('%s AS %s' % (field_sel, c_alias))
+                col_aliases.add(c_alias)
+                aliases.add(c_alias)
+            else:
+                r = field_sel
+                result.append(r)
+                aliases.add(r)
+                if with_aliases:
+                    col_aliases.add(field.column)
+        return result, aliases
+
+    def resolve_columns(self, row, fields=()):
+        """
+        This routine is necessary so that distances and geometries returned
+        from extra selection SQL get resolved appropriately into Python
+        objects.
+        """
+        values = []
+        aliases = list(self.query.extra_select)
+
+        # Have to set a starting row number offset that is used for
+        # determining the correct starting row index -- needed for
+        # doing pagination with Oracle.
+        rn_offset = 0
+        if self.connection.ops.oracle:
+            if self.query.high_mark is not None or self.query.low_mark: rn_offset = 1
+        index_start = rn_offset + len(aliases)
+
+        # Converting any extra selection values (e.g., geometries and
+        # distance objects added by GeoQuerySet methods).
+        values = [self.query.convert_values(v,
+                               self.query.extra_select_fields.get(a, None),
+                               self.connection)
+                  for v, a in zip(row[rn_offset:index_start], aliases)]
+        if self.connection.ops.oracle or getattr(self.query, 'geo_values', False):
+            # We resolve the rest of the columns if we're on Oracle or if
+            # the `geo_values` attribute is defined.
+            for value, field in zip_longest(row[index_start:], fields):
+                values.append(self.query.convert_values(value, field, self.connection))
+        else:
+            values.extend(row[index_start:])
+        return tuple(values)
+
+    #### Routines unique to GeoQuery ####
+    def get_extra_select_format(self, alias):
+        sel_fmt = '%s'
+        if hasattr(self.query, 'custom_select') and alias in self.query.custom_select:
+            sel_fmt = sel_fmt % self.query.custom_select[alias]
+        return sel_fmt
+
+    def get_field_select(self, field, alias=None, column=None):
+        """
+        Returns the SELECT SQL string for the given field.  Figures out
+        if any custom selection SQL is needed for the column  The `alias`
+        keyword may be used to manually specify the database table where
+        the column exists, if not in the model associated with this
+        `GeoQuery`.  Similarly, `column` may be used to specify the exact
+        column name, rather than using the `column` attribute on `field`.
+        """
+        sel_fmt = self.get_select_format(field)
+        if field in self.query.custom_select:
+            field_sel = sel_fmt % self.query.custom_select[field]
+        else:
+            field_sel = sel_fmt % self._field_column(field, alias, column)
+        return field_sel
+
+    def get_select_format(self, fld):
+        """
+        Returns the selection format string, depending on the requirements
+        of the spatial backend.  For example, Oracle and MySQL require custom
+        selection formats in order to retrieve geometries in OGC WKT. For all
+        other fields a simple '%s' format string is returned.
+        """
+        if self.connection.ops.select and hasattr(fld, 'geom_type'):
+            # This allows operations to be done on fields in the SELECT,
+            # overriding their values -- used by the Oracle and MySQL
+            # spatial backends to get database values as WKT, and by the
+            # `transform` method.
+            sel_fmt = self.connection.ops.select
+
+            # Because WKT doesn't contain spatial reference information,
+            # the SRID is prefixed to the returned WKT to ensure that the
+            # transformed geometries have an SRID different than that of the
+            # field -- this is only used by `transform` for Oracle and
+            # SpatiaLite backends.
+            if self.query.transformed_srid and ( self.connection.ops.oracle or
+                                                 self.connection.ops.spatialite ):
+                sel_fmt = "'SRID=%d;'||%s" % (self.query.transformed_srid, sel_fmt)
+        else:
+            sel_fmt = '%s'
+        return sel_fmt
+
+    # Private API utilities, subject to change.
+    def _field_column(self, field, table_alias=None, column=None):
+        """
+        Helper function that returns the database column for the given field.
+        The table and column are returned (quoted) in the proper format, e.g.,
+        `"geoapp_city"."point"`.  If `table_alias` is not specified, the
+        database table associated with the model of this `GeoQuery` will be
+        used.  If `column` is specified, it will be used instead of the value
+        in `field.column`.
+        """
+        if table_alias is None: table_alias = self.query.get_meta().db_table
+        return "%s.%s" % (self.quote_name_unless_alias(table_alias),
+                          self.connection.ops.quote_name(column or field.column))
+
+class SQLInsertCompiler(compiler.SQLInsertCompiler, GeoSQLCompiler):
+    pass
+
+class SQLDeleteCompiler(compiler.SQLDeleteCompiler, GeoSQLCompiler):
+    pass
+
+class SQLUpdateCompiler(compiler.SQLUpdateCompiler, GeoSQLCompiler):
+    pass
+
+class SQLAggregateCompiler(compiler.SQLAggregateCompiler, GeoSQLCompiler):
+    pass
+
+class SQLDateCompiler(compiler.SQLDateCompiler, GeoSQLCompiler):
+    """
+    This is overridden for GeoDjango to properly cast date columns, since
+    `GeoQuery.resolve_columns` is used for spatial values.
+    See #14648, #16757.
+    """
+    def results_iter(self):
+        if self.connection.ops.oracle:
+            from django.db.models.fields import DateTimeField
+            fields = [DateTimeField()]
+        else:
+            needs_string_cast = self.connection.features.needs_datetime_string_cast
+
+        offset = len(self.query.extra_select)
+        for rows in self.execute_sql(MULTI):
+            for row in rows:
+                date = row[offset]
+                if self.connection.ops.oracle:
+                    date = self.resolve_columns(row, fields)[offset]
+                elif needs_string_cast:
+                    date = typecast_date(str(date))
+                if isinstance(date, datetime.datetime):
+                    date = date.date()
+                yield date
+
+class SQLDateTimeCompiler(compiler.SQLDateTimeCompiler, GeoSQLCompiler):
+    """
+    This is overridden for GeoDjango to properly cast date columns, since
+    `GeoQuery.resolve_columns` is used for spatial values.
+    See #14648, #16757.
+    """
+    def results_iter(self):
+        if self.connection.ops.oracle:
+            from django.db.models.fields import DateTimeField
+            fields = [DateTimeField()]
+        else:
+            needs_string_cast = self.connection.features.needs_datetime_string_cast
+
+        offset = len(self.query.extra_select)
+        for rows in self.execute_sql(MULTI):
+            for row in rows:
+                datetime = row[offset]
+                if self.connection.ops.oracle:
+                    datetime = self.resolve_columns(row, fields)[offset]
+                elif needs_string_cast:
+                    datetime = typecast_timestamp(str(datetime))
+                # Datetimes are artifically returned in UTC on databases that
+                # don't support time zone. Restore the zone used in the query.
+                if settings.USE_TZ:
+                    datetime = datetime.replace(tzinfo=None)
+                    datetime = timezone.make_aware(datetime, self.query.tzinfo)
+                yield datetime
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/conversion.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/conversion.py
new file mode 100644
index 0000000..160b623
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/conversion.py
@@ -0,0 +1,27 @@
+"""
+This module holds simple classes used by GeoQuery.convert_values
+to convert geospatial values from the database.
+"""
+
+class BaseField(object):
+    empty_strings_allowed = True
+    def get_internal_type(self):
+        "Overloaded method so OracleQuery.convert_values doesn't balk."
+        return None
+
+class AreaField(BaseField):
+    "Wrapper for Area values."
+    def __init__(self, area_att):
+        self.area_att = area_att
+
+class DistanceField(BaseField):
+    "Wrapper for Distance values."
+    def __init__(self, distance_att):
+        self.distance_att = distance_att
+
+class GeomField(BaseField):
+    """
+    Wrapper for Geometry values.  It is a lightweight alternative to 
+    using GeometryField (which requires an SQL query upon instantiation).
+    """
+    pass
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/query.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/query.py
new file mode 100644
index 0000000..5877f29
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/query.py
@@ -0,0 +1,121 @@
+from django.db import connections
+from django.db.models.query import sql
+
+from django.contrib.gis.db.models.fields import GeometryField
+from django.contrib.gis.db.models.sql import aggregates as gis_aggregates
+from django.contrib.gis.db.models.sql.conversion import AreaField, DistanceField, GeomField
+from django.contrib.gis.db.models.sql.where import GeoWhereNode
+from django.contrib.gis.geometry.backend import Geometry
+from django.contrib.gis.measure import Area, Distance
+
+
+ALL_TERMS = set([
+            'bbcontains', 'bboverlaps', 'contained', 'contains',
+            'contains_properly', 'coveredby', 'covers', 'crosses', 'disjoint',
+            'distance_gt', 'distance_gte', 'distance_lt', 'distance_lte',
+            'dwithin', 'equals', 'exact',
+            'intersects', 'overlaps', 'relate', 'same_as', 'touches', 'within',
+            'left', 'right', 'overlaps_left', 'overlaps_right',
+            'overlaps_above', 'overlaps_below',
+            'strictly_above', 'strictly_below'
+            ])
+ALL_TERMS.update(sql.constants.QUERY_TERMS)
+
+class GeoQuery(sql.Query):
+    """
+    A single spatial SQL query.
+    """
+    # Overridding the valid query terms.
+    query_terms = ALL_TERMS
+    aggregates_module = gis_aggregates
+
+    compiler = 'GeoSQLCompiler'
+
+    #### Methods overridden from the base Query class ####
+    def __init__(self, model, where=GeoWhereNode):
+        super(GeoQuery, self).__init__(model, where)
+        # The following attributes are customized for the GeoQuerySet.
+        # The GeoWhereNode and SpatialBackend classes contain backend-specific
+        # routines and functions.
+        self.custom_select = {}
+        self.transformed_srid = None
+        self.extra_select_fields = {}
+
+    def clone(self, *args, **kwargs):
+        obj = super(GeoQuery, self).clone(*args, **kwargs)
+        # Customized selection dictionary and transformed srid flag have
+        # to also be added to obj.
+        obj.custom_select = self.custom_select.copy()
+        obj.transformed_srid = self.transformed_srid
+        obj.extra_select_fields = self.extra_select_fields.copy()
+        return obj
+
+    def convert_values(self, value, field, connection):
+        """
+        Using the same routines that Oracle does we can convert our
+        extra selection objects into Geometry and Distance objects.
+        TODO: Make converted objects 'lazy' for less overhead.
+        """
+        if connection.ops.oracle:
+            # Running through Oracle's first.
+            value = super(GeoQuery, self).convert_values(value, field or GeomField(), connection)
+
+        if value is None:
+            # Output from spatial function is NULL (e.g., called
+            # function on a geometry field with NULL value).
+            pass
+        elif isinstance(field, DistanceField):
+            # Using the field's distance attribute, can instantiate
+            # `Distance` with the right context.
+            value = Distance(**{field.distance_att : value})
+        elif isinstance(field, AreaField):
+            value = Area(**{field.area_att : value})
+        elif isinstance(field, (GeomField, GeometryField)) and value:
+            value = Geometry(value)
+        elif field is not None:
+            return super(GeoQuery, self).convert_values(value, field, connection)
+        return value
+
+    def get_aggregation(self, using):
+        # Remove any aggregates marked for reduction from the subquery
+        # and move them to the outer AggregateQuery.
+        connection = connections[using]
+        for alias, aggregate in self.aggregate_select.items():
+            if isinstance(aggregate, gis_aggregates.GeoAggregate):
+                if not getattr(aggregate, 'is_extent', False) or connection.ops.oracle:
+                    self.extra_select_fields[alias] = GeomField()
+        return super(GeoQuery, self).get_aggregation(using)
+
+    def resolve_aggregate(self, value, aggregate, connection):
+        """
+        Overridden from GeoQuery's normalize to handle the conversion of
+        GeoAggregate objects.
+        """
+        if isinstance(aggregate, self.aggregates_module.GeoAggregate):
+            if aggregate.is_extent:
+                if aggregate.is_extent == '3D':
+                    return connection.ops.convert_extent3d(value)
+                else:
+                    return connection.ops.convert_extent(value)
+            else:
+                return connection.ops.convert_geom(value, aggregate.source)
+        else:
+            return super(GeoQuery, self).resolve_aggregate(value, aggregate, connection)
+
+    # Private API utilities, subject to change.
+    def _geo_field(self, field_name=None):
+        """
+        Returns the first Geometry field encountered; or specified via the
+        `field_name` keyword.  The `field_name` may be a string specifying
+        the geometry field on this GeoQuery's model, or a lookup string
+        to a geometry field via a ForeignKey relation.
+        """
+        if field_name is None:
+            # Incrementing until the first geographic field is found.
+            for fld in self.model._meta.fields:
+                if isinstance(fld, GeometryField): return fld
+            return False
+        else:
+            # Otherwise, check by the given field name -- which may be
+            # a lookup to a _related_ geographic field.
+            return GeoWhereNode._check_geo_field(self.model._meta, field_name)
diff --git a/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/where.py b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/where.py
new file mode 100644
index 0000000..c29533b
--- /dev/null
+++ b/lib/python2.7/site-packages/django/contrib/gis/db/models/sql/where.py
@@ -0,0 +1,91 @@
+from django.db.models.constants import LOOKUP_SEP
+from django.db.models.fields import FieldDoesNotExist
+from django.db.models.sql.expressions import SQLEvaluator
+from django.db.models.sql.where import Constraint, WhereNode
+from django.contrib.gis.db.models.fields import GeometryField
+
+class GeoConstraint(Constraint):
+    """
+    This subclass overrides `process` to better handle geographic SQL
+    construction.
+    """
+    def __init__(self, init_constraint):
+        self.alias = init_constraint.alias
+        self.col = init_constraint.col
+        self.field = init_constraint.field
+
+    def process(self, lookup_type, value, connection):
+        if isinstance(value, SQLEvaluator):
+            # Make sure the F Expression destination field exists, and
+            # set an `srid` attribute with the same as that of the
+            # destination.
+            geo_fld = GeoWhereNode._check_geo_field(value.opts, value.expression.name)
+            if not geo_fld:
+                raise ValueError('No geographic field found in expression.')
+            value.srid = geo_fld.srid
+        db_type = self.field.db_type(connection=connection)
+        params = self.field.get_db_prep_lookup(lookup_type, value, connection=connection)
+        return (self.alias, self.col, db_type), params
+
+class GeoWhereNode(WhereNode):
+    """
+    Used to represent the SQL where-clause for spatial databases --
+    these are tied to the GeoQuery class that created it.
+    """
+
+    def _prepare_data(self, data):
+        if isinstance(data, (list, tuple)):
+            obj, lookup_type, value = data
+            if ( isinstance(obj, Constraint) and
+                 isinstance(obj.field, GeometryField) ):
+                data = (GeoConstraint(obj), lookup_type, value)
+        return super(GeoWhereNode, self)._prepare_data(data)
+
+    def make_atom(self, child, qn, connection):
+        lvalue, lookup_type, value_annot, params_or_value = child
+        if isinstance(lvalue, GeoConstraint):
+            data, params = lvalue.process(lookup_type, params_or_value, connection)
+            spatial_sql, spatial_params = connection.ops.spatial_lookup_sql(
+                    data, lookup_type, params_or_value, lvalue.field, qn)
+            return spatial_sql, spatial_params + params
+        else:
+            return super(GeoWhereNode, self).make_atom(child, qn, connection)
+
+    @classmethod
+    def _check_geo_field(cls, opts, lookup):
+        """
+        Utility for checking the given lookup with the given model options.
+        The lookup is a string either specifying the geographic field, e.g.
+        'point, 'the_geom', or a related lookup on a geographic field like
+        'address__point'.
+
+        If a GeometryField exists according to the given lookup on the model
+        options, it will be returned.  Otherwise returns None.
+        """
+        # This takes into account the situation where the lookup is a
+        # lookup to a related geographic field, e.g., 'address__point'.
+        field_list = lookup.split(LOOKUP_SEP)
+
+        # Reversing so list operates like a queue of related lookups,
+        # and popping the top lookup.
+        field_list.reverse()
+        fld_name = field_list.pop()
+
+        try:
+            geo_fld = opts.get_field(fld_name)
+            # If the field list is still around, then it means that the
+            # lookup was for a geometry field across a relationship --
+            # thus we keep on getting the related model options and the
+            # model field associated with the next field in the list
+            # until there's no more left.
+            while len(field_list):
+                opts = geo_fld.rel.to._meta
+                geo_fld = opts.get_field(field_list.pop())
+        except (FieldDoesNotExist, AttributeError):
+            return False
+
+        # Finally, make sure we got a Geographic field and return.
+        if isinstance(geo_fld, GeometryField):
+            return geo_fld
+        else:
+            return False
author	ttt	2017-05-13 00:29:47 +0530
committer	ttt	2017-05-13 00:29:47 +0530
commit	4336f5f06f61de30ae3fa54650fce63a9d5ef5be (patch)
tree	23b4ee9b8e8f24bf732acf2f7ad22ed50cdd5670 /lib/python2.7/site-packages/django/contrib/gis/db/models
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