一个简单的图形处理程序，读取地理数据，绘制显示地图，实现了地物的符号化。具有放大、缩小、漫游，元素选取、拖动、选取、删除等基本功能-A simple graphical procedure, read the geographic data, map display maps, to achieve the features of the symbol. With enlarged, reduced, roaming, select e