这是我写的一个实现点选中多边形的数值算法，算法进行了特别设计，速度很快，可以判断点在浮点型的多变形中或在多边形外，可以移植到UNIX或linux平台，因为这两个平台没有CRect的PtInRect() 和 CRgn的PtInRgn（）函数，这是一个很高效的算法-This is the one I wrote to achieve Polygon click the numerical algorithm, the algorithm specifically designed, very fas

The grass documentation for beginners, and Grass is one of the largest GIS open source application. Widely spread in Europe, hopefully in the future, open source will be growing the same speed as it is in Europe. Now let begin with the basic manipula