PostGIS 1.5.8 Manual - Fedora Project Packages GIT repositories

PostGIS 1.5.8 Manual217 / 310This method implements the SQL/MM specification. SQL-MM 3: 5.1.16This function supports 3d and will not drop the z-index.Examples--Get estimate of infected area based on point observationsSELECT d.disease_type,ST_ConvexHull(ST_Collect(d.the_geom)) As the_geomFROM disease_obs As dGROUP BY d.disease_type;Convex Hull of a MultiLinestring and a MultiPoint seen together with the MultiLinestring and MultiPointSELECT ST_AsText(ST_ConvexHull(ST_Collect(ST_GeomFromText(’MULTILINESTRING((100 190,10 8),(150 10, 20 30))’),ST_GeomFromText(’MULTIPOINT(50 5, 150 30, 50 10, 10 10)’))) );---st_astext--POLYGON((50 5,10 8,10 10,100 190,150 30,150 10,50 5))See AlsoST_Collect, ST_MinimumBoundingCircle7.9.5 ST_CurveToLineST_CurveToLine — Converts a CIRCULARSTRING/CURVEDPOLYGON to a LINESTRING/POLYGONSynopsisgeometry ST_CurveToLine(geometry curveGeom);geometry ST_CurveToLine(geometry curveGeom, integer segments_per_qtr_circle);