In regards to a convcave hull you might want to check this thread: http://www.mail-archive.com/[email protected]/msg05979.html
nico [email protected] schrieb: > Hallo > > you can read about it here: > http://www.postgis.org/documentation/manual-svn/ST_ConvexHull.html > ST_ConvexHull will give you a better result but as you see in the > documentation there is no function that gives a concave hull as you have in > your example link. > > /Nicklas > > > > 2009-02-12 My Pid wrote: > > Hello, >> I am really a newbie in the postgis world. >> >> I am a developper for http://www.openbmap.org/ website >> which identify GSM cell area from measures of GSM data >> and GPS coordinates. >> >> So I am planning to go from mysql to postgresql/postgis >> and I am looking for a function that does the following: >> >> I have a table containing the gps coordinates mentionned above. >> I would like to generate a enveloppe or a boundary of the area >> of the GSM cell. >> >> What I have tried (among others) >> >> SELECT ST_AsText(ST_Envelope(ST_Collect(gps_coordinates))) FROM >> "208_1_14592_gps"; >> >> with gps_coordinates - POINT geometry >> >> It seems to output a 4 points polygons and I would like to get something like >> >> http://realtimeblog.free.fr/cell_map.php?mcc=208&mnc=1&lac=14592&cellid=62403&display=Display >> >> >> >> Is it possible to use postgis functions to generate this kind of envelope ? >> >> regards, >> Nick >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> 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
