Road Map Of .1:500 To 1:5000 City Blocks Automatically Integrated

The traditional cartographic generalization requires highly skilled cartographer with practical experience and various professional technique. Although it is an arduous and error-prone process, the systematization of the theory and method provide fundaments for the research on the automatic generalization of digital maps. The cartographic generalization is a scientific method for solving the contradiction between the miniature cartographic presentation and the complicated objective world. However, its application is limited by the using purpose of the map, the scale of the map and the geographic feature of the mapped region etc.. The using purpose determines the thesis and the emphasis of the map and influences the inclination and the degree of the cartographic generalization. The scale determines the volume and detail of the map content.At present the principal theory and method of cartographic generalization have formed a methodology for scientific research on cartography. With the assistance of modern applied mathematics and computer science, the research on cartographic generalization has been furthered and drawn much attention worldwide. The automatic generalization of large-scale map is a difficult problem in the cartographic field. Many problems found in the cartographic generalization can not be depicted by mathematic models. For example, the automatic generalization of urban roads involves the 2-dimensional graphing, which is very difficult, because the relations of the roads are complex and it is difficult to process. However the geometric characters of the urban road can be efficiently expressed by the algorithm of fractal analysis. It is a significant project on cartography and an important content of future automatic cartography to analyze the feasibility of cartographic generalization from the new points of view about fractal analysis. Then it introduces the methodology and algorithmic models for cartographic generalization by analyzing the trends and status in the art of cartography. In short, the cartographic generalization is theoretically and practically meaningful and plays an important role in cartography and GIS.This paper discussed the relation between fractal analysis and cartographic generalization, applied the theory of fractal analysis to the automatic generalization of urban roads and ameliorated the algorithm of the polygonal automatic generalization based on the geometric characters of cartographic urban roads. This generalization program of road built a model ofurban road network selection by using Delaunay Triangulation to explore the continuous topological relation among the polygons. Moreover, in this programming process the model of square root principle was employed to determine the type and amount of various factors that may represent the characters of urban roads. Aaccording to fractal analysis method, the area of road is the primary factor. After this, optimum roads were decided by some fators, for example the importance of road. Then the polygons of these roads were converted linear essentials and later the map of the urban roads was generalized with Douglas-Peucker Algorithm.Bases on the detailed analysis of the urban road characters, a road automatic generalization system was designed on the ArcGIS programming platform.This system can fulfill the automatic generalization of urban roads from the 1:500 scale map to 1:5000. This experiment proved the feasibility and superiority of fractal analysis in cartographic generalization.The results of the experiment showed that the fractal analysis method can concretize the abstract problems, because the method can construct the proper mathematical models according to the related geographical information. The auto-similarity of fractal analysis gives the rules of structure-configuration character of cartographic objects. So, the fractal analysis method can effectively improve the intelligentization on cartographic generalization.