Research On The Theories & Methods Of Electronic Map's Multi-Scale Representation

With the updates of technology and the development of map's conception, map has had great effects in many fields, such as city planning, geology exploration etc. So more electronic maps are needed. On the one hand, these demands promote the progress of cartography; on the other hand, these take a great challenge: we must make the maps that are satisfied by users. The research on the theories and methods of electronic map's multi-scale representation is brought forward as a new study project to rise to the challenge. The author discusses the electronic map's multi-scale representation theoretically and practically, after analyzing and studying the interrelated research results in this paper. The main content are abstracted as follows:1) The mode and meaning of the electronic map's multi-scale representation are discussed, and the author put forward that the multi-scale representation of electronic map is a form of map representation which is mainly based on the visual perceive, and taken the computer operator as assistant means. Then the author narrates that the basic means of the electronic map's multi-scale representation is simplification.2) The relationship between electronic map's multi-scale representation, the scale of data, and the resolution of computer screen is analyzed, then a formulation of these elements mentioned above is given. The author put forward that the method that simplifies the Voronoi diagram dynamically could be used to the point and area elements multi-scale representation. Take habitation and relief as instances, this paper presents the general model and basic algorithm of elements with different dimensions. For the habitation multi-scale representation, this paper put forward the second level neighbouring points discriminance to solve the combine with geographic locations and attributions. And for the relief multi-scale representation, this paper put forward the consistency problem of setting, then gives the resolve methods.3) Discuss the multi-scale representation of multiple scale data set with huge capacity, analyze the data structure and algorithm of representation of multiple scale data set with huge capacity, use the quad-tree structure realizing the no-boundary ramble and different scale data auto switch.4) Adopt the method of psychology-physics experimentation to discuss the color scheme of electronic map and verify the effect of the electronic map's multi-scale representation. Finally, sum up the rules of electronic map's representation from map area load.