| 等高线的空间关系规则和渐进式图形简化方法 |
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| 引用本文： | 郭庆胜,毋河海,李沛川.等高线的空间关系规则和渐进式图形简化方法[J].武汉大学学报(信息科学版),2000,25(1). |
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| 作者姓名： | 郭庆胜 毋河海 李沛川 |
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| 作者单位： | 武汉测绘科技大学土地科学学院,武汉市珞喻路129号,430079 |
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| 基金项目： | 国家测绘局测绘科技发展基金，教育部霍英东青年教师基金!编号97010 |
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| 摘 要： | 详细讨论了等高线表达地形的规则和以此为基础自动建立等高线关系的方法，对地形特征点、线的提取改进了已有较成熟的方法，建立了一套实用的等高线图形简化的渐进式方法，并对其特殊情况的处理提 出了具体的算法。这种方法把不同比例尺跨度的等高线图形综合融为一体，易于实现，等高线图形简化时的等高线相交可在综合过程中控制。
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| 关 键 词： | 等高线 图形简化 地形特征 渐进式地图综合 |
Spatial Relation Rules and Progressive Graphic Simplification of Contours |
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| GUO Qingsheng,WU Hehai,LI Peichuan.Spatial Relation Rules and Progressive Graphic Simplification of Contours[J].Geomatics and Information Science of Wuhan University,2000,25(1). |
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| Authors: | GUO Qingsheng WU Hehai LI Peichuan |
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| Abstract: | Contour lines are a discrete representation of relief, but topographic stir face is a continuous surface. Contours must be used to represent relief according to some rules. In this paper, two kinds of rules are shown. One is mathematical rule, the other is cartographic rule. With respect to these rules, the relationship between contour lines can be found. The direction of contour can be adjusted automatically. After that, the elevation of left part of contour line is higher than that of right part. The contour tree structure is saved in certain table. The topographic terrain represented by contour lines is not complete. Based on the spatial relationships and the characteristic points of contour lines, the ridge lines and ravine lines can be linked partly. The rivers must be the ravine lines. The intersection between contours and rivers are the characteristic points. The important degrees of characteristic points are given according to complex degree of bends in contour lines. The important degrees of the ridge lines and ravine lines are given according to the important degrees of characteristic points associated with that. This information is stored in two structure tables. The basic idea of progressive graphic simplification of contour lines is that the result of sudden change can be got from the progressive change. The self-closed contour can be handled by using the same method of self-closed linear feature progressive generalization. In generalization of other contours, firstly, the characteristic points, which are not associated with ridge and ravine, are handled progressively; the minimal bend is deleted with respect to the area of bend and important degree of the characteristic point. Then bends associated with ridges and ravines are handled according to important degree of the characteristic points and lines from small important degree to large important degree. The special cases in this method are shown and the algorithms of resolving these problems are given. |
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| Keywords: | contour line graphic simplification topographic terrain feature progressive map generalization |
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