vc＋＋ 平台实现的，采用对话框形式，利用mapx工具编程，实现 放大，缩小，还原，测量距离，查看图层信息等功能，适合初学者-vc platform to achieve, using the dialog box, using MapX tool for programming, to achieve amplification, reduced, reduction, measuring the distance to see features such as layers of i