GENERATION OF A ROAD NETWORK INCLUDING THE GRADIENTS OF ROADS BY DIGITAL ELEVATION MODEL ：APPLICATION TO FUEL CONSUMPTION MINIMUM PATH SEARCH
In this research, we propose a method to generate a road network which includes the gradients of road segments. Using the generated network data, we search an optimal path that minimizes the fuel consumption. Path search calculates a path and length from a starting point to destination. However, maps commonly used for path search are two-dimensional, and information regarding gradieqdnts is not included. Since the speed of a vehicle is affected by gradients, the gradients of roads may influence on the selection of a path. We perform a path search considering the gradients of roads by generating a map that includes information regarding gradients. This would achieve a path search to save fuel consumption and to avoid uphill. We give an elevation value to each node by combining road network and Digital Elevation Model data. If the nodes at the endpoints of a link have different elevations, the link has a gradient. The fuel consumption along a link is calculated considering both the gradient and length of the link. The minimum fuel consumption path search calculates the fuel consumption for a single destination from all the other starting points. In the results of an experiment, the fuel consumption was saved approximately 7.8% in total compared with the conventional shortest path method. The elevations of the selected path are low compared with the shortest path. The proposed method can search paths with less fuel consumption than the shortest path because almost the entire paths had been changed.