PostGIS 实现了点、线、面、多点、多线、多面等的SQL实现参考。...select npoints(polygon '((1,1),(0,0))');2pclose(path)path将开放path转换为闭合pathselect pclose(path '[(0,0),(...1,1),(2,0)]');((0,0),(1,1),(2,0))popen(path)path将闭合path转换为开放pathselect popen(path '((0,0),(1,1),(2,0)...)获取多边形的第N个内边界ST_EndPoint(geometry)获取线的终点ST_StartPoint(geometry)获取线的起始点ST_GeometryType(geometry)获取几何对象的类型...(box ‘((0,0),(1,1))’);((0,0),(0,1),(1,1),(1,0))polygon(circle)polygon圆形转12点多边形select polygon(circle ‘