delphi开发的计算机地图制图演示程序，数据格式是bna以及xys。功能包括地图显示（放大、缩小、漫游）以及图层管理和符号设计-computer cartography delphi development demonstration program, the data format is bna and xys. Functions including map display (zoom in, zoom out, roaming), and layer management and des