测试点是否落在多边形内，其中包括多边形内岛的判断。此文件使用时必须包含shapefil.h, openshp.c, 和opendbf.c等shape lib中的文件。-Whether test points fall within the polygon, including polygons, i. judgments. This document must be included when used shapefil.h, openshp.c, and opendbf.c such as s