Generalization of Road Maps in GIS By Dual Graph

Geographic information systems to map the different situations require different details and different representations. For example¡ the map display to a user who is driving at high speed must be different from the user is standing or moving at low speeds. At higher speeds the lower scales with low details should be done to make the best map used by the user. Maps with different scales and different details must be done intelligently and automatically. In this research¡ in addition to addressing the methods of map generalization and simplification¡ for automatic extraction of various displays of the map¡ a new approach was used based on the dual graph. Dual graph are a modification of graph that is defined to facilitate and simplify the problems in graph. A variety of dual graphs have been used in different fields. We will show that based on the concept of one of the dual graph¡ the capabilities and efficiency of GIS in providing map with different details could be increased. Thus the topology and relationships between urban streets was involved in the extraction of various map displays.