From: Regina Obe Date: Sun, 24 May 2009 07:52:07 +0000 (+0000) Subject: update to include behavior for 3D and also note this seems to go beyond what the... X-Git-Tag: 1.4.0b1~41 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cf5f2e696347d795c8b202b0881c18d9d07ce8fc;p=postgis update to include behavior for 3D and also note this seems to go beyond what the spec defines. git-svn-id: http://svn.osgeo.org/postgis/trunk@4098 b70326c6-7e19-0410-871a-916f4a2858ee --- diff --git a/doc/reference.xml b/doc/reference.xml index ec63081be..976ac608c 100644 --- a/doc/reference.xml +++ b/doc/reference.xml @@ -11007,7 +11007,17 @@ st_perimeter This method implements the SQL/MM - specification: SQL-MM 3: 8.1.5, 9.5.6 + specification: SQL-MM 3: 8.1.5, 9.5.6. + According to the specs, ST_PointOnSurface works for surface geometries (POLYGONs, MULTIPOLYGONS, CURVED POLYGONS). So PostGIS seems to be extending what + the spec allows here. Most databases Oracle,DB II, ESRI SDE seem to only support this function for surfaces. SQL Server 2008 like PostGIS supports for all common geometries. + + + + + + + + This function supports 3d (only for POINT,MULTIPOINT, LINESTRING, MULTILINESTRING) and will not drop the z-index. @@ -11029,7 +11039,14 @@ SELECT ST_AsText(ST_PointOnSurface('POLYGON((0 0, 0 5, 5 5, 5 0, 0 0))'::geometr st_astext ---------------- POINT(2.5 2.5) -(1 row) +(1 row) + +SELECT ST_AsEWKT(ST_PointOnSurface(ST_GeomFromEWKT('LINESTRING(0 5 1, 0 0 1, 0 10 2)'))); + st_asewkt +---------------- + POINT(0 0 1) +(1 row) +