Space Graphic Expression Recognition And Synthesis

People always want to solve the problem of map automatic generalization since computer technology was applied in cartography. Until the 21st century, there is not a perfect method to solve it. After analyzing and studying the interrelated literature, the author puts forward the theory of automatic generalization for spatial graphics from a fire-new point of view, and there are also some new arithmetic and new models in this dissertation. From theory to practice, a systemic research is made by the author. The main achievements are the follows:1. The aim, essence, object and method of map automatic generalization are disused. The study makes a summarization including the history of map generalization concept, its theory, arithmetic, research institution and production, and then defines the concept of automatic generalization for spatial graphics. The author thinks that the main conflict is the infinite geography objects and the finite capability, the course of generalization should be spire. And forecast the developing orientation.2. The map space can be divided into graphics space and attribute space. The complicated geography objects are abstracted into simple spatial graphics, including point(s), line(s) and area(s). They are depicted using a math way and their spatial relationship are studied. A new theory of automatic generalization for spatial graphics is educed. That is representation, identification and generalization.3. To represent point-cluster, the study builds Delaunay triangular network. The shape identification includes outline, inside structure, center- axis and the extension of single point. The model of point-cluster automatic generalization is formed and applied in the seabed terrain.4. On the basis of analyzing the line object structure, the study presents curve Douglas binary tree to represent it. The shape identification includes the local character point and its direction, the curve structure, the global parameter and topology trait. The model of line automatic generalization accords with the seeing continuity theory. The coastline and the isobath are selected in the experimentation.5. The study represents net object by designing the path system model and identifies the shape parameter. A test is made using the road net and the river net which are typical.6. Using the contour tree and the similar Douglas conversion, the physiognomy is represented. The contour relationship, terrain character point, orographic character line and physiognomy style are identified. At last, the model of physiognomy automatic generalization is building and its validity is validated by the experiment.