Then use ForceRHR to get the rings clockwise followed by Reverse to get the order you want (counter clockwise).
P On Wed, Sep 30, 2009 at 11:09 AM, Peter Freimuth <[email protected]> wrote: > Picavet Vincent schrieb: >> Hello, >> >> >>> today i am searching for a postgis based solution which gives >>> me an answer on the question >>> >>> isClockwise(POLYGON) >>> >>> and if this is true >>> >>> reverseWindingOrder(POLYGON) >>> >>> >> >> PostGIS provides the following function : >> >> ST_ForceRHR(geometry) >> Force polygons of the collection to obey Right-Hand-Rule. >> >> Does that suit your needs or you really want to test if your polygon is >> clockwise ? >> >> Regards, >> Vincent >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > Hi Vincent, > thanks for the quick and good response. Yes, i would like to check if > the vertices of a polygon without inner rings are in a > clockwise/counterclockwise order so that i can use |ST_Reverse to change > this. > At the end i want to dump the coordinates of a polygon in > counterclockwise order using something like the dump_points function as > described here > http://www.spatialdbadvisor.com/postgis_tips_tricks/109/implementing-oracles-getvertices-function-in-postgis-st_dumppoints/ > ! > Kind regards, > Peter > > | > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
