ST_SimplifyVW — Returns a "simplified" version of the given geometry using the Visvalingam-Whyatt algorithm
geometry ST_SimplifyVW(
geometry geomA, float tolerance)
;
Returns a "simplified" version of the given geometry using the Visvalingam-Whyatt algorithm. Will actually do something only with (multi)lines and (multi)polygons but you can safely call it with any kind of geometry. Since simplification occurs on a object-by-object basis you can also feed a GeometryCollection to this function.
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Note that returned geometry might loose its simplicity (see ST_IsSimple) |
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Note topology may not be preserved and may result in invalid geometries. Use (see ST_SimplifyPreserveTopology) to preserve topology. |
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This function handles 3D and the third dimmension will affect the result |
Availability: 2.2.0
A linestring that get the efffective area calculated. All points is returned since we give 0 as themin area threashold
select ST_AStext(ST_SimplifyVW(geom,30)) simplified FROM (SELECT 'LINESTRING(5 2, 3 8, 6 20, 7 25, 10 10)'::geometry geom) As foo; -result simplified -----------+-------------------+ LINESTRING(5 2,7 25,10 10)