All Intelligent Transport Systems (ITS) which exchange data and information with other systems, whatever the level of complexity, need location referencing methods. Location referencing methods are required to provide geo-referenced information (e.g. accidents location, route suggestions). All the methods in use are based on the GPS navigation system and consequently have to be able to obtain the WGS84 co-ordinates pair for each point belonging to the area involved in the ITS application. Unfortunately, the maps currently available at low cost from local administrative offices do not provide this kind of information. It is neither difficult nor expensive to find a map, and co-ordinates like UTM or similar co-ordinates (Gauss-Boaga in Italy) can be easily associated (but not WGS84 co-ordinates). This paper aims at explaining how it is possible to convert the geographic WGS84 co-ordinates pair to the cartographic UTM co-ordinates pair (North, East) and vice versa. The exposed method is based on the result of studies which have been conducted in the city of Torino, where the available cartographic information was based on the Gauss-Boaga projection. The reported conversion formulas allow a maximum conversion error of only a few meters, adequate to a great part of ITS applications.
Samenvatting