Research On Rapid Production Techniques Of Thematic Maps Based On Knowledge Base

Thematic maps play an important role in emergency decision-making of natural disasters such as earthquake, agroforestry disasters. While traditional manual drafting have been replaced by convenient and efficient computer mapping, there is still no higher automated mapping system existed so far. Strong interactive cartographic work still needs large number of cartographers’ duplicative efforts. So there are many problems to be resolved such as how to guarantee make maps in relatively short time, or how to solve the problems of low maintenance efficiency caused by non-standardized mapping and excessive map templates. To solve these problems, ontology, knowledge base theory, and parallel computing technique were used to research how to generate thematic maps quickly in this paper. Quick mapping techniques were described in both theoretical and practical ways, and applied in the production of earthquake disaster thematic maps and GCM(Geographical conditions monitoring) thematic maps. The main contents and results are as follows:(1) The expression of thematic mapping knowledge. The existing experiences of the thematic map production were classified and formalized, so that they can be identified by computer systems correctly. The knowledge is used to record the differences among requirements of different thematic maps in different fields. Finally, the mapping knowledge base were built with mapping knowledge and knowledge base system techniques.(2) Research and develop mapping system based on the knowledge base. The mapping system including thematic map manager module, data manager module, rule manager module, output devices manager module, was developed based on ArcObject SDK and mapping knowledge base system. The system can mapping semi-automatically by analysis knowledge and rules stored in knowledge base system.(3) Applied parallel computing techniques in terrain rendering process. To solve the time-consuming problem in the mapping process, this paper compared the consuming time between serial computing and parallel computing spent in computing terrain factors. And in the condition of the trial environment the speed-up can reach 6 or more.(4) Applied in earthquake disaster thematic maps and GCM thematic maps. The mapping system based on knowledge base can separate map production and professional cartographers, and knowledge plays a core role in it. With a comprehensive knowledge base, the system can produce about 180 thematic maps using mixed outputting ways in 30 minutes.