多边形的求差算法。可以实现两个任意多边形（没有岛的存在）之间的剪裁。

这个源码的功能为在arcgis技术的基础之上，对地图进行瓦片剪裁的效果，希望对大家有用处。-The source function is based on technology in the arcgis, cut tiles on the effect of the map, I hope to be useful

用python操作arcgis，实现矢量剪裁栅格数据的批量处理，而且用户可以安装wxpython看到操作界面，也可以只复制中间代码直接操作。-Cutting operation in python arcgis, the realization of vector raster data of batch processing, and user can install wxpython see operation interface, direct manipulation can only