Electronic Map In The Car Navigation System

In this paper, the application of Global Position System (GPS) and Geographical Information System (GIS) on vehicle positioning and navigation is studied. Starting from the Component Object Model (COM) technique, the paper introduces the MapX ActiveX based on the OLE (Object Linking and Embedding) technique, a component GIS. The paper discusses how to develop the software of vehicle navigation system by using MapX control as a graphics tool and MSComm control as a communication tool with Visual C++ 6.0.The serial communication between PC and GPS receiver is realized by this software . The software can receive and process GPS data, and it accomplishes the basic function of editing, analyzing and querying the spatial data and attributive data. The paper discusses the transformation problem between different types of coordinate systems, for example: the coordinate transformation between WGS-84 coordinate system and Beijing 54 coordinate system, the formula for Gauss projection positive and negative computation in national stripes and any local projective stripes, and presents an algorithm. Combined with some classic shortest path algorithms, this paper presents an efficient method of realize the shortest path algorithm which is based on Dijkstra algorithm.