专题图符号扫描输出中的图案方法

本文基于用图案来组成图形符号的基本思想,引入图案拓扑等价的观点,较系统地对专题地图中点、线、面三类符号的绘制作了一些探讨。

A Patterning Method for Mapping by Using Thematic Symbols in Raster Form

There are many symbols in thematic cartography.These symbols can be classified into three kinds:point symbls,line symbols and area symbols.For computer-aided cartography it would he wasteful if we give each symbol a special drawing program. Therefore,We try to make a commonly used program that draws as many thematic symbols as possible. This paper is a trial in this aspect.The paper is based on the idea that we can use patterns to form the thematic symbols.Some researches were made systematicly for drawing the point,line and area thematic symbols. The basic ideas of drawing the point,line and area thematic symbols are as follows 1.Point symbols The point thematic symbols include geometric symbols,literal symbols and art sym- bols.The symbols themselves can be regarded as patterns.The patterns arc stored in the pattern base.when a symbol is to be drawn,the symbolic pattern is obtained from the pattern base.Then after egual or similar transformation the pattern is put on the correct place of the map. 2.Line symbols we can say the line symbols are made of patterns if we make some topologic trans- formation on the patterns.The line thematic symbols can be formed by a series of pat- terns on which the topologic transformation is made. 3.Area symbols we suppose that the area symbols can be made by filling reqularly in the defined area with the symbolic patterns. Furthermore,the paper discusses also the method of creating and using the pattern base.