These captured images were imported into the GIS software MAP, a product of AuTODesk in raster form and were then converted into digital form. For converting raster drawings into digital form the tools or utilities available in MAP were used. Using these utilities three types of objects, nodes, lines and polygons, can be digitized. The raster drawing was kept in one layer and the objects were traced into another layer. After the objects were traced from raster image, the layer consisting of raster image was put off and the file was saved as GIS file. The zonal map and road network were traced into separate layers. The maps of the traffic zones and road network are shown in Fig. 1 & 2 respectively.
Fig. 1 Zonal Map of Calicut City
Fig 2 Road Network Map of Calicut City
During the process of digitization many types of errors crept in. These errors were corrected using the clean up tools available in MAP, such as duplicate objects, erase short objects, break crossing objects, extend undershoots, erase dangling objects, simplify linear objects, snap cluster nodes, dissolve pseudo nodes and edge matching. Thus the graphic data consisting of two layers, one representing zones and the other road network, was developed. In the zonal map each zone was represented as polygon and the road links in road network were represented as linear objects. [Page] 3.2 Non-Graphic Data
The non-graphic data consisted the details of traffic zones and the road network. The non-graphic database was created using the inbuilt data base utilities. The database of traffic zones, which are the electoral wards of Calicut city, consis
