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-- ST_ConcaveHull --
WITH hull AS (
SELECT ST_Buffer(ST_MakePoint(0,0),1) AS geom
)
SELECT 'concavehull01-poly' as test,
abs(ST_Area(geom) - ST_Area(ST_ConcaveHull(geom, 1.0))) < 0.01 AS area_convex
FROM hull;
WITH hull AS (
SELECT ST_Difference(
ST_Buffer(ST_MakePoint(0,0),10),
ST_Translate(ST_Buffer(ST_MakePoint(0,0),10), 5, 0)) AS geom
)
SELECT 'concavehull02-poly' as test,
ST_Area(ST_ConcaveHull(geom, 0.5)) > 0.0 AS area_non_zero,
ST_GeometryType(ST_ConcaveHull(geom, 0.5)) AS type,
ST_Area(ST_ConcaveHull(geom, 0.5, true)) > 0.0 AS nohole_area_non_zero
FROM hull;
-- ST_ConcaveHull --
WITH hull AS (
SELECT ST_Buffer(ST_MakePoint(0,0),1) AS geom
)
SELECT 'concavehull01-points' as test,
abs(ST_Area(geom) - ST_Area(ST_ConcaveHull(ST_Points(geom), 1.0))) < 0.01 AS area_convex
FROM hull;
WITH hull AS (
SELECT ST_Difference(
ST_Buffer(ST_MakePoint(0,0),10),
ST_Translate(ST_Buffer(ST_MakePoint(0,0),10), 5, 0)) AS geom
)
SELECT 'concavehull02-points' as test,
ST_Area(ST_ConcaveHull(ST_Points(geom), 0.5)) > 0.0 AS area_non_zero,
ST_GeometryType(ST_ConcaveHull(ST_Points(geom), 0.5)) AS type,
ST_Area(ST_ConcaveHull(ST_Points(geom), 0.5, true)) > 0.0 AS nohole_area_non_zero
FROM hull;
-- ST_SimplifyPolygonHull
SELECT 'simplifypolygonhull-1' AS test,
ST_AsText(ST_SimplifyPolygonHull('POLYGON((0 0, 0 1, 1 1, 1 0, 0 0))'::geometry, 0.5),1);
SELECT 'simplifypolygonhull-2' AS test,
ST_AsText(ST_SimplifyPolygonHull(
'POLYGON((0 0, 0 1, 0.5 0.1, 1 1, 1 0, 0 0))'::geometry,
0.5),1);
SELECT 'simplifypolygonhull-3' AS test,
ST_AsText(ST_SimplifyPolygonHull(
'POLYGON((0 0, 0 1, 0.5 0.1, 0.5 0.1, 1 1, 1 0, 0 0))'::geometry,
0.85),1);
-- ST_TriangulatePolygon --
select 'triangulatepolygon-1' AS text,
ST_AsText(ST_Normalize(ST_TriangulatePolygon('POLYGON((0 0, 0 1, 1 1, 1 0, 0 0))')), 1);
select 'triangulatepolygon-2' AS text,
ST_AsText(ST_Normalize(ST_TriangulatePolygon('MULTIPOLYGON(((0 0, 0 1, 1 1, 1 0, 0 0)))')), 1);
select 'triangulatepolygon-3' AS text,
ST_AsText(ST_Normalize(ST_TriangulatePolygon('LINESTRING(0 0, 0 1, 1 1, 1 0, 0 0)')), 1);
select 'triangulatepolygon-4' AS text,
ST_AsText(ST_Normalize(ST_TriangulatePolygon('POINT(1 0)')), 1);
select 'triangulatepolygon-5' AS text,
ST_AsText(ST_Normalize(ST_TriangulatePolygon(
'GEOMETRYCOLLECTION(POLYGON((0 0,0 1,1 1,0 0)),POLYGON((1 1,1 0,0 0,1 1)), POINT(1 1))'
)), 1);
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