Area of a single closed polygon (simple x-y coordinate input) or of multiple polygons, possibly with holes.
一个单一的封闭的多边形(简单的xy坐标输入)或多个多边形的区域,可能有孔。
用法----------Usage----------
polyarea(xy, ha = TRUE)
参数----------Arguments----------
参数:xy
dataframe or list with components "x" and "y", or a SpatialPolygons or SpatialPolygonsDataFrame object from package sp
数据框或与组件×和y,或SpatialPolygons或SpatialPolygonsDataFrame对象列表从套件sp
参数:ha
logical if TRUE output is converted from square metres to hectares
如果真正输出转换逻辑平方米公顷
Details
详细信息----------Details----------
For SpatialPolygons or SpatialPolygonsDataFrame objects it is necessary to have installed the packages sp and rgeos.
对于SpatialPolygons或SpatialPolygonsDataFrame对象是必要的,已经安装的包sp和rgeos。