def __to_sql_expr_box(self):
coords = self.values['box']
epsg = self.geom_column.type.srid
if self.epsg is not None:
epsg = self.epsg
coords = map(float, coords)
# define polygon from box
point_a = (coords[0], coords[1])
point_b = (coords[0], coords[3])
point_c = (coords[2], coords[3])
point_d = (coords[2], coords[1])
point_e = point_a
coords = (point_a, point_b, point_c, point_d, point_e)
poly = Polygon(coords)
pg_poly = func.geomfromtext(poly.wkt, epsg)
if epsg != self.geom_column.type.srid:
pg_poly = func.transform(pg_poly, epsg)
# TODO : use st_intersects when only postgis 1.3 supported
return self.geom_column.op('&&')(pg_poly) and \
func.intersects(self.geom_column, pg_poly)
def to_sql_expr(self):
if self.type == self.BOX:
geometry = self.__box_to_geometry()
if self.type == self.WITHIN:
geometry = Point(self.values['lon'], self.values['lat'])
if self.type == self.GEOMETRY:
factory = lambda ob: GeoJSON.to_instance(ob)
geometry = loads(self.values['geometry'], object_hook=factory)
geometry = asShape(geometry)
if self.epsg != self.geom_column.type.srid:
geom_column = func.transform(self.geom_column, self.epsg)
else:
geom_column = self.geom_column
tolerance = self.values['tolerance']
pg_geometry = func.geomfromtext(geometry.wkt, self.epsg)
return and_(func.expand(pg_geometry, tolerance).op('&&')(geom_column),
func.distance(geom_column, pg_geometry) <= tolerance)
def __to_sql_expr_within(self):
lon = self.values['lon']
lat = self.values['lat']
tolerance = self.values['tolerance']
epsg = self.geom_column.type.srid
if self.epsg is not None:
epsg = self.epsg
point = Point(lon, lat)
pg_point = func.pointfromtext(point.wkt, epsg)
geom = self.geom_column
if epsg != self.geom_column.type.srid:
geom = func.transform(geom, epsg)
# TODO : use st_dwithin when only Postgis 1.3 supported
if tolerance is not None and tolerance > 0:
e = func.expand(geom, tolerance).op('&&')(pg_point) and \
(func.distance(geom, pg_point) < tolerance)
else:
e = func.within(pg_point, geom)
return e
