本程序是用C编写的数字地图制图实习的源程序，主要实现四个功能：绘制晕线，晕线填充，绘制土堤以及绘制点状符号-this process is the preparation of the C Digital Cartography internship program, the four main functions : Drawing halo lines, Halo filled with earth berms and the mapping of drawing point symbols