由直线和曲线混合组成的地形符号在DCS中的处理

在ＤＣＳ输出的地籍图上，有许多由直线段和曲线段组成的地物符号，用传统方法处理难以取得理想的绘图效果。本文在分析ＤＣＳ数据结构和属性码的基础上，提出了曲线部分按三次参数样条曲线逼近，讨论了直线段和曲线段的各种组合情况，并且通过正确地选择边值条件使二者之间．的连接比较符合实际。最后扼要分析了该类线段按虚线绘出时的处理方法。

The Treatment of Topographical Figures Containing Lines With Straight and Curve Parts in DCS

There are lots of figures containing both straight and curve parts on the cadastre maps output by DCS. It is difficult to reach an ideal plotting result for this sort of figures with traditional methods. On the basis of analysing the data structure and attribute codes. a method of treating this kind of lines is put forward. i. e. approximating the curve part with the cubic parameter spline function and linking the straight and curve parts smoothly or arbitrarily by properly choosing the end conditions. All of the possible conditions between the straight and curve parts are discussed. At last. the methods of plotting this sort of lines in the form of dash lines are also briefly analysed.