Hi all, I'm not able to compute the area of a polygon using G_area_of_polygon,
I define a square with coords: [(0, 0), (0, 2), (2, 2), (2, 0), (0, 0)]) with: >>> from pygrass.vector.geometry import Boundary >>> bound = Boundary(points=[(0, 0), (0, 2), (2, 2), (2, 0), (0, 0)]) Check the content of the C structure, with: >>> for i in xrange(bound.c_points.contents.n_points): ... print i, " (%.1f, %.1f)" % (bound.c_points.contents.x[i], bound.c_points.contents.y[i]) ... 0 (0.0, 0.0) 1 (0.0, 2.0) 2 (2.0, 2.0) 3 (2.0, 0.0) 4 (0.0, 0.0) It seems ok to me, now use the G_area_polygon function... >>> import grass.lib.gis as libgis >>> libgis.G_area_of_polygon(bound.c_points.contents.x, ... bound.c_points.contents.y, ... bound.c_points.contents.n_points) 0.0 Why G_area_of_polygon doesn't return 4.0? What is it wrong? Best regards Pietro _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
