ST_BuildArea — Creates an areal geometry formed by the constituent linework of given geometry
geometry ST_BuildArea(
geometry A)
;
Creates an areal geometry formed by the constituent linework of given geometry. The return type can be a Polygon or MultiPolygon, depending on input. If the input lineworks do not form polygons NULL is returned. The inputs can be LINESTRINGS, MULTILINESTRINGS, POLYGONS, MULTIPOLYGONS, and GeometryCollections.
This function will assume all inner geometries represent holes
Input linework must be correctly noded for this function to work properly |
Availability: 1.1.0 - requires GEOS >= 2.1.0.
SELECT ST_BuildArea(ST_Collect(smallc,bigc)) FROM (SELECT ST_Buffer( ST_GeomFromText('POINT(100 90)'), 25) As smallc, ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As bigc) As foo;
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SELECT ST_BuildArea(ST_Collect(line,circle)) FROM (SELECT ST_Buffer( ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190)), 5) As line, ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo; --this creates the same gaping hole --but using linestrings instead of polygons SELECT ST_BuildArea( ST_Collect(ST_ExteriorRing(line),ST_ExteriorRing(circle)) ) FROM (SELECT ST_Buffer( ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190)) ,5) As line, ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo;
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ST_Node, ST_MakePolygon, ST_BdPolyFromText, ST_BdMPolyFromTextwrappers to this function with standard OGC interface