def create_route(self, start_pt, target_pt):
"""
Based on points passed through a HTTP request a route is calculated, geometry generated on the basis of it
and persisted to the database.
:param start_pt: the start point specified
:param target_pt: the end point specified
:return: the id of the generated and persisted route geometry back to the page which requested it
"""
start_end = grid_utils.GridUtilities.start_end_points_to_cells(start_pt, target_pt)
start_node = start_end[0]
end_node = start_end[1]
reverse_path = self.path_finder.find_path(start_node, end_node, self.gra.graph_dict)
path = self.path_finder.rebuild_path(reverse_path[0], start_node, end_node)
route_geoms = _generate_route_geom(path)
start_pt_record = GridUtilities.find_cell_centre_projected(start_node, self.qs)
end_pt_record = GridUtilities.find_cell_centre_projected(end_node, self.qs)
route = TestRoutes(name='Route No {}'.format(random.randint(1, 100000)),
distance=round(route_geoms[0].length/1852, 2),
geom=route_geoms[0],
geom_4326=route_geoms[1],
start_geom=start_pt_record,
end_geom=end_pt_record)
route.save()
return route.gid
def _generate_route_geom(path):
"""
Helper method which looks after the conversion of a list of geometry ids to a line
which can be persisted in the database and displayed on screen
:param path:
:return: a linestring geometry representing the route calculated
"""
waypoints_proj = []
waypoints_geo = []
for item in path:
cell = PathGrid.objects.get(pk=item)
centre_point_geo = GridUtilities.convert_to_latlon(cell.geom.centroid)
centre_point_proj = cell.geom.centroid
waypoints_proj.append(centre_point_proj)
waypoints_geo.append(centre_point_geo)
route_line_proj = LineString(waypoints_proj, srid=32616)
route_line_geom = LineString(waypoints_geo, srid=4326)
return route_line_proj, route_line_geom