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git-svn-id: http://svn.osgeo.org/postgis/trunk@14869 b70326c6-7e19-0410-871a-916f4a2858ee
42 lines
1.9 KiB
SQL
42 lines
1.9 KiB
SQL
-- Tests to confirm the concave hull area is <= convex hull and
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-- covers the original geometry (can't use covers because always gives topo errors with 3.3
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SELECT
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'ST_ConcaveHull MultiPolygon 0.95', ST_Area(ST_Intersection(geom,ST_ConcaveHull(
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geom, 0.95) )) = ST_Area(geom) As encloses_geom,
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(ST_Area(ST_ConvexHull(geom))
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- ST_Area(ST_ConcaveHull(geom, 0.95))) < (0.95 * ST_Area(ST_ConvexHull(geom) ) ) As reached_target
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FROM ST_Union(ST_GeomFromText('POLYGON((175 150, 20 40,
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50 60, 125 100, 175 150))'),
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ST_Buffer(ST_GeomFromText('POINT(110 170)'), 20)
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) As geom;
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SELECT
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'ST_ConcaveHull Lines 0.80', ST_Intersection(geom,ST_ConcaveHull(
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geom, 0.80) ) = geom As encloses_geom,
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(ST_Area(ST_ConvexHull(geom))
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- ST_Area(ST_ConcaveHull(geom, 0.80))) < (0.80 * ST_Area(ST_ConvexHull(geom) ) ) As reached_target
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FROM ST_GeomFromText('MULTILINESTRING((106 164,30 112,74 70,82 112,130 94,
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130 62,122 40,156 32,162 76,172 88),
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(132 178,134 148,128 136,96 128,132 108,150 130,
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170 142,174 110,156 96,158 90,158 88),
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(22 64,66 28,94 38,94 68,114 76,112 30,
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132 10,168 18,178 34,186 52,184 74,190 100,
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190 122,182 148,178 170,176 184,156 164,146 178,
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132 186,92 182,56 158,36 150,62 150,76 128,88 118))') As geom;
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-- test holes vs. no holes - holes should still enclose but have smaller area than no holes --
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SELECT
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'ST_ConcaveHull Lines 0.80 holes', ST_Intersection(geom,ST_ConcaveHull(
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geom, 0.80, true) ) = geom As encloses_geom,
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ST_Area(ST_ConcaveHull(geom, 0.80, true)) < ST_Area(ST_ConcaveHull(geom, 0.80)) As reached_target
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FROM ST_GeomFromText('MULTILINESTRING((106 164,30 112,74 70,82 112,130 94,
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130 62,122 40,156 32,162 76,172 88),
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(132 178,134 148,128 136,96 128,132 108,150 130,
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170 142,174 110,156 96,158 90,158 88),
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(22 64,66 28,94 38,94 68,114 76,112 30,
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132 10,168 18,178 34,186 52,184 74,190 100,
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190 122,182 148,178 170,176 184,156 164,146 178,
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132 186,92 182,56 158,36 150,62 150,76 128,88 118))') As geom;
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