Python backend.Geometry方法代码示例

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def convert_extent(self, clob, srid):
        if clob:
            # Generally, Oracle returns a polygon for the extent -- however,
            # it can return a single point if there's only one Point in the
            # table.
            ext_geom = Geometry(clob.read(), srid)
            gtype = str(ext_geom.geom_type)
            if gtype == 'Polygon':
                # Construct the 4-tuple from the coordinates in the polygon.
                shell = ext_geom.shell
                ll, ur = shell[0][:2], shell[2][:2]
            elif gtype == 'Point':
                ll = ext_geom.coords[:2]
                ur = ll
            else:
                raise Exception('Unexpected geometry type returned for extent: %s' % gtype)
            xmin, ymin = ll
            xmax, ymax = ur
            return (xmin, ymin, xmax, ymax)
        else:
            return None 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def _geo_field(self, field_name=None):
        """
        Returns the first Geometry field encountered or the one specified via
        the `field_name` keyword. The `field_name` may be a string specifying
        the geometry field on this GeoQuerySet'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 field in self.model._meta.fields:
                if isinstance(field, GeometryField):
                    return field
            return False
        else:
            # Otherwise, check by the given field name -- which may be
            # a lookup to a _related_ geographic field.
            return GISLookup._check_geo_field(self.model._meta, field_name) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def __init__(self, obj, geography=False):
        """
        Initialize on the spatial object.
        """
        self.is_geometry = isinstance(obj, (Geometry, PostGISAdapter))

        # Getting the WKB (in string form, to allow easy pickling of
        # the adaptor) and the SRID from the geometry or raster.
        if self.is_geometry:
            self.ewkb = bytes(obj.ewkb)
            self._adapter = Binary(self.ewkb)
        else:
            self.ewkb = to_pgraster(obj)

        self.srid = obj.srid
        self.geography = geography 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
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) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def _get_db_prep_lookup(self, lookup_type, value, connection):
        """
        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.

        Only used by the deprecated GeoQuerySet and to be
        RemovedInDjango20Warning.
        """
        # 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])]
            # Getting the distance parameter in the units of the field.
            params += self.get_distance(value[1:], lookup_type, connection)
        else:
            params = [connection.ops.Adapter(value)]
        return params


# The OpenGIS Geometry Type Fields 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def as_postgresql(self, compiler, connection):
        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info
        if self.source_is_geography():
            # Set parameters as geography if base field is geography
            for pos, expr in enumerate(
                    self.source_expressions[self.geom_param_pos + 1:], start=self.geom_param_pos + 1):
                if isinstance(expr, GeomValue):
                    expr.geography = True
        elif geo_field.geodetic(connection):
            # Geometry fields with geodetic (lon/lat) coordinates need special distance functions
            if self.spheroid:
                # DistanceSpheroid is more accurate and resource intensive than DistanceSphere
                self.function = connection.ops.spatial_function_name('DistanceSpheroid')
                # Replace boolean param by the real spheroid of the base field
                self.source_expressions[2] = Value(geo_field._spheroid)
            else:
                self.function = connection.ops.spatial_function_name('DistanceSphere')
        return super(Distance, self).as_sql(compiler, connection) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def convert_geometry(self, value, expression, connection, context):
        if value:
            value = Geometry(value)
            if 'transformed_srid' in context:
                value.srid = context['transformed_srid']
        return value 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def convert_geom(self, value, geo_field):
        if value:
            if isinstance(value, Database.LOB):
                value = value.read()
            return Geometry(value, geo_field.srid)
        else:
            return None 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def convert_geom(self, hex, geo_field):
        """
        Converts the geometry returned from PostGIS aggregates.
        """
        if hex:
            return Geometry(hex, srid=geo_field.srid)
        else:
            return None 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def convert_extent(self, box, srid):
        """
        Convert the polygon data received from Spatialite to min/max values.
        """
        if box is None:
            return None
        shell = Geometry(box, srid).shell
        xmin, ymin = shell[0][:2]
        xmax, ymax = shell[2][:2]
        return (xmin, ymin, xmax, ymax) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
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.
        """
        value = super(GeometryField, self).get_prep_value(value)
        if isinstance(value, Expression):
            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 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def from_db_value(self, value, expression, connection, context):
        if value and not isinstance(value, Geometry):
            value = Geometry(value)
        return value 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
def contribute_to_class(self, cls, name, **kwargs):
        super(GeometryField, self).contribute_to_class(cls, name, **kwargs)

        # Setup for lazy-instantiated Geometry object.
        setattr(cls, self.attname, SpatialProxy(Geometry, self)) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
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.
        """
        # special case for isnull lookup
        if lookup_type == 'isnull':
            return []
        elif lookup_type in self.class_lookups:
            # 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 self.class_lookups[lookup_type].distance:
                    # 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, Expression):
                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__)) 

# 需要导入模块: from django.contrib.gis.geometry import backend [as 别名]
# 或者: from django.contrib.gis.geometry.backend import Geometry [as 别名]
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)