From: Regina Obe Date: Tue, 7 Oct 2008 17:39:00 +0000 (+0000) Subject: Move over ST_ConvexHull X-Git-Tag: 1.4.0b1~651 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=aff378de9f78cda5575337cec466388a62f40190;p=postgis Move over ST_ConvexHull git-svn-id: http://svn.osgeo.org/postgis/trunk@3071 b70326c6-7e19-0410-871a-916f4a2858ee --- diff --git a/doc/reference.xml b/doc/reference.xml index 3408e1cf7..90e2c40d1 100644 --- a/doc/reference.xml +++ b/doc/reference.xml @@ -113,30 +113,6 @@ - - ST_ConvexHull(geometry) - - - The convex hull of a geometry represents the minimum closed - geometry that encloses all geometries within the set. - - It is usually used with MULTI and Geometry Collections. - Although it is not an aggregate - you can use it in conjunction - with ST_Collect to get the convex hull of a set of points. - ST_ConvexHull(ST_Collect(somepointfield)). It is often used to - determine an affected area based on a set of point - observations. - - SELECT d.disease_type, ST_ConvexHull(ST_Collect(d.the_geom)) As the_geom - FROM disease_obs As d - GROUP BY d.disease_type - - Performed by the GEOS module - - OGC SPEC s2.1.1.3 - - - ST_Shift_Longitude(geometry) @@ -1657,24 +1633,6 @@ WHERE n*100.00/length < 1; SQL-MM 3: 5.1.14 - - - ST_ConvexHull - - - The convex hull of a geometry represents the minimum geometry - that encloses all geometries within the set. - - It is usually used with MULTI and Geometry Collections. - Although it is not an aggregate - you can use it in conjunction with - ST_Collect to get the convex hull of a set of points. - ST_ConvexHull(ST_Collect(somepointfield)). It is often used to - determine an affected area based on a set of point - observations. - - SQL-MM 3: 5.1.16 - - ST_CoordDim diff --git a/doc/reference_new.xml b/doc/reference_new.xml index 9c31c9f06..f44899ac1 100644 --- a/doc/reference_new.xml +++ b/doc/reference_new.xml @@ -5040,6 +5040,83 @@ SELECT ST_AsEWKT(ST_Collect(ST_GeomFromEWKT('POINT(1 2 3)'), , + + + + ST_ConvexHull + The convex hull of a geometry represents the minimum closed + geometry that encloses all geometries within the set. + + + + + + geometryST_ConvexHull + geometry geomA + + + + + + Description + The convex hull of a geometry represents the minimum closed + geometry that encloses all geometries within the set. + + It is usually used with MULTI and Geometry Collections. + Although it is not an aggregate - you can use it in conjunction + with ST_Collect to get the convex hull of a set of points. + ST_ConvexHull(ST_Collect(somepointfield)). + + It is often used to + determine an affected area based on a set of point + observations. + + Performed by the GEOS module + + + + This method implements the + OpenGIS Simple + Features Implementation Specification for SQL OGC SPEC s2.1.1.3 + + + + + + + This function supports 3d and will not drop the z-index, but sometimes does something goofy with + the z-index (elevation) when polygons are involved. + + + + + + + This method implements the SQL/MM specification: SQL-MM 3: 5.1.16 + + + + + Examples +SELECT d.disease_type, + ST_ConvexHull(ST_Collect(d.the_geom)) As the_geom + FROM disease_obs As d + GROUP BY d.disease_type; + + SELECT ST_AsEWKT(ST_ConvexHull( + ST_Collect( + ST_GeomFromEWKT('LINESTRING(1 2 3,3 4 5)'), + ST_MakePoint(0, 2, 0)) + )); + ---st_asewkt-- + POLYGON((0 2 0,3 4 5,1 2 3,0 2 0)) + + + + See Also + + +