[postgis-tickets] [SCM] PostGIS branch master updated. 3.2.0-791-gbefb35508
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- Log -----------------------------------------------------------------
commit befb35508018f4e860139d9fba5ef63d575c86f6
Author: Regina Obe <lr at pcorp.us>
Date: Wed May 4 14:17:18 2022 -0400
More standardization of examples, fix copy paste, sort functions
diff --git a/doc/html/image_src/st_alphashape01.wkt b/doc/html/image_src/st_alphashape01.wkt
index c781fb7c7..04eb400df 100644
--- a/doc/html/image_src/st_alphashape01.wkt
+++ b/doc/html/image_src/st_alphashape01.wkt
@@ -1,2 +1,2 @@
-Result;POLYGON((26 20,32 36,35 45,39 55,43 69,50 84,57 100,63 118,68 133,74 149,81 164,88 180,101 180,112 180,119 164,126 149,132 131,139 113,143 100,150 84,157 69,163 51,168 36,174 20,163 20,150 20,143 36,139 49,132 64,114 64,99 64,90 69,81 64,63 64,57 49,52 36,46 20,37 20,26 20),(74 93,81 109,88 124,92 138,103 138,110 122,114 109,121 96,112 82,99 82,83 82,74 93))
-ArgA-thin;MULTIPOINT ((132 64), (114 64), (99 64), (81 64), (63 64), (57 49), (52 36), (46 20), (37 20), (26 20), (32 36), (39 55), (43 69), (50 84), (57 100), (63 118), (68 133), (74 149), (81 164), (88 180), (101 180), (112 180), (119 164), (126 149), (132 131), (139 113), (143 100), (150 84), (157 69), (163 51), (168 36), (174 20), (163 20), (150 20), (143 36), (139 49), (132 64), (99 151), (92 138), (88 124), (81 109), (74 93), (70 82), (83 82), (99 82), (112 82), (126 82), (121 96), (114 109), (110 122), (103 138), (99 151), (34 27), (43 31), (48 44), (46 58), (52 73), (63 73), (61 84), (72 71), (90 69), (101 76), (123 71), (141 62), (166 27), (150 33), (159 36), (146 44), (154 53), (152 62), (146 73), (134 76), (143 82), (141 91), (130 98), (126 104), (132 113), (128 127), (117 122), (112 133), (119 144), (108 147), (119 153), (110 171), (103 164), (92 171), (86 160), (88 142), (79 140), (72 124), (83 131), (79 118), (68 113), (63 102), (68 93), (35 45))
+Result;POLYGON((134 80,136 75,130 63,126 52,135 45,132 44,126 28,117 24,110 24,98 24,93 33,80 27,82 39,72 51,60 48,52 52,42 50,34 54,39 66,40 81,34 90,36 100,48 98,54 110,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,90 135,104 129,108 142,114 132,112 126,112 116,116 110,120 108,125 108,128 106,125 96,132 87,134 80))
+ArgA-thin;MULTIPOINT((94 126),(114 132),(102 110),(80 27),(136 75),(122 105),(132 44),(36 123),(48 76),(56 34),(40 81),(126 28),(112 130),(66 63),(116 100),(135 45),(54 92),(48 98),(122 70),(132 87),(102 110),(74 142),(122 90),(130 75),(117 24),(118 32),(45 33),(117 64),(39 128),(72 51),(52 52),(54 60),(46 118),(125 44),(40 126),(78 147),(108 142),(128 106),(112 126),(112 116),(122 44),(116 110),(61 63),(125 108),(34 54),(134 80),(40 86),(86 146),(40 116),(58 132),(90 122),(120 108),(81 48),(82 39),(93 33),(105 30),(114 40),(126 52),(130 63),(123 81),(125 96),(104 129),(90 135),(75 129),(64 120),(54 110),(54 102),(60 112),(36 100),(34 90),(39 66),(42 50),(60 48),(64 28),(98 24),(110 24),(57 69),(46 88),(51 129),(68 135),(96 146))
diff --git a/doc/reference_sfcgal.xml b/doc/reference_sfcgal.xml
index 36e8013e4..8eb6c478d 100644
--- a/doc/reference_sfcgal.xml
+++ b/doc/reference_sfcgal.xml
@@ -84,21 +84,18 @@
</refentry>
- <refentry id="ST_Extrude">
+ <refentry id="ST_3DArea">
<refnamediv>
- <refname>ST_Extrude</refname>
+ <refname>ST_3DArea</refname>
- <refpurpose>Extrude a surface to a related volume</refpurpose>
+ <refpurpose>Computes area of 3D surface geometries. Will return 0 for solids.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_Extrude</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
- <paramdef><type>float</type> <parameter>x</parameter></paramdef>
- <paramdef><type>float</type> <parameter>y</parameter></paramdef>
- <paramdef><type>float</type> <parameter>z</parameter></paramdef>
+ <funcdef>float<function>ST_3DArea</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -114,87 +111,40 @@
</refsection>
<refsection><title>Examples</title>
- <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
+ <para>Note: By default a PolyhedralSurface built from WKT is a surface geometry, not solid. It therefore has surface area. Once converted to a solid, no area.</para>
+<programlisting>SELECT ST_3DArea(geom) As cube_surface_area,
+ ST_3DArea(ST_MakeSolid(geom)) As solid_surface_area
+ FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
+ ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
+ ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
+ ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
+ ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
+ ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para>
- <programlisting>SELECT ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30);</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_extrude01.png" />
- </imageobject>
- <caption><para>Original octagon formed from buffering point</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30);</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_extrude02.png" />
- </imageobject>
- <caption><para>Hexagon extruded 30 units along Z produces a PolyhedralSurfaceZ</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
+ cube_surface_area | solid_surface_area
+-------------------+--------------------
+ 6 | 0 </programlisting>
- <row>
- <entry><para>
- <programlisting>SELECT ST_GeomFromText('LINESTRING(50 50, 100 90, 95 150)')</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_extrude03.png" />
- </imageobject>
- <caption><para>Original linestring</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>SELECT ST_Extrude(
- ST_GeomFromText('LINESTRING(50 50, 100 90, 95 150)'),0,0,10));</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_extrude04.png" />
- </imageobject>
- <caption><para>LineString Extruded along Z produces a PolyhedralSurfaceZ</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
</refsection>
<refsection>
- <title>See Also</title>
+ <title>See Also</title>
- <para><xref linkend="ST_AsX3D" /></para>
- </refsection>
+ <para><xref linkend="ST_Area" />, <xref linkend="ST_MakeSolid" />, <xref linkend="ST_IsSolid" />, <xref linkend="ST_Area" /></para>
+ </refsection>
</refentry>
-
- <refentry id="ST_StraightSkeleton">
+ <refentry id="ST_3DConvexHull">
<refnamediv>
- <refname>ST_StraightSkeleton</refname>
+ <refname>ST_3DConvexHull</refname>
- <refpurpose>Compute a straight skeleton from a geometry</refpurpose>
+ <refpurpose>Computes the 3D convex hull of a geometry.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_StraightSkeleton</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <funcdef>geometry <function>ST_3DConvexHull</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -202,151 +152,249 @@
<refsection>
<title>Description</title>
- <para>Availability: 2.1.0</para>
+ <para>Availability: 3.3.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- <refsection><title>Examples</title>
- <programlisting>SELECT ST_StraightSkeleton(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, 190 20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));</programlisting>
+ <refsection>
+ <title>Examples</title>
+ <programlisting>SELECT ST_AsText(ST_3DConvexHull('LINESTRING Z(0 0 5, 1 5 3, 5 7 6, 9 5 3 , 5 7 5, 6 3 5)'::geometry));</programlisting>
+ <screen>POLYHEDRALSURFACE Z (((1 5 3,9 5 3,0 0 5,1 5 3)),((1 5 3,0 0 5,5 7 6,1 5 3)),((5 7 6,5 7 5,1 5 3,5 7 6)),((0 0 5,6 3 5,5 7 6,0 0 5)),((6 3 5,9 5 3,5 7 6,6 3 5)),((0 0 5,9 5 3,6 3 5,0 0 5)),((9 5 3,5 7 5,5 7 6,9 5 3)),((1 5 3,5 7 5,9 5 3,1 5 3)))</screen>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para><informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_straightskeleton01.png" />
- </imageobject>
- <caption><para>Original polygon</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para><informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_straightskeleton02.png" />
- </imageobject>
- <caption><para>Straight Skeleton of polygon</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
+ <programlisting>WITH f AS (SELECT i, ST_Extrude(geom, 0,0, i ) AS geom
+FROM ST_Subdivide(ST_Letters('CH'),5) WITH ORDINALITY AS sd(geom,i)
+ )
+ SELECT ST_3DConvexHull(ST_Collect(f.geom) )
+ FROM f;</programlisting>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3dconvexhull.png" />
+ </imageobject>
+ <caption><para>Original geometry overlaid with 3D convex hull</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para>
+ </refsection>
+ <refsection>
+ <title>See Also</title>
+ <para><xref linkend="ST_Letters" />, <xref linkend="ST_AsX3D" /></para>
</refsection>
-
</refentry>
- <refentry id="ST_ApproximateMedialAxis">
+ <refentry id="ST_3DIntersection">
<refnamediv>
- <refname>ST_ApproximateMedialAxis</refname>
+ <refname>ST_3DIntersection</refname>
- <refpurpose>Compute the approximate medial axis of an areal geometry.</refpurpose>
+ <refpurpose>Perform 3D intersection</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_ApproximateMedialAxis</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <funcdef>geometry <function>ST_3DIntersection</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
+ <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
-
- <para>
-Return an approximate medial axis for the areal input based on
-its straight skeleton. Uses an SFCGAL specific API when built against
-a capable version (1.2.0+). Otherwise the function is just a wrapper
-around ST_StraightSkeleton (slower case).
- </para>
-
- <para>Availability: 2.2.0</para>
+ <para>Return a geometry that is the shared portion between geom1 and geom2.</para>
+ <para>Availability: 2.1.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- <refsection><title>Examples</title>
- <programlisting>SELECT ST_ApproximateMedialAxis(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, 190 20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));</programlisting>
-
- <informaltable>
- <tgroup cols="1">
- <tbody>
- <row>
- <entry><para><informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_approximatemedialaxis01.png" />
- </imageobject>
- <caption><para>A polygon and its approximate medial axis</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
- </refsection>
-
<refsection>
- <title>See Also</title>
+ <title>Examples</title>
+ <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2;
+ </programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3ddifference01.png" />
+ </imageobject>
+ <caption><para>Original 3D geometries overlaid. geom2 is shown semi-transparent</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>SELECT ST_3DIntersection(geom1,geom2)
+FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3dintersection01.png" />
+ </imageobject>
+ <caption><para>Intersection of geom1 and geom2</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
- <para><xref linkend="ST_StraightSkeleton" /></para>
- </refsection>
+ <para>3D linestrings and polygons</para>
+ <programlisting> SELECT ST_AsText(ST_3DIntersection(linestring, polygon)) As wkt
+FROM ST_GeomFromText('LINESTRING Z (2 2 6,1.5 1.5 7,1 1 8,0.5 0.5 8,0 0 10)') AS linestring
+ CROSS JOIN ST_GeomFromText('POLYGON((0 0 8, 0 1 8, 1 1 8, 1 0 8, 0 0 8))') AS polygon;
- </refentry>
+ wkt
+--------------------------------
+ LINESTRING Z (1 1 8,0.5 0.5 8)
+ </programlisting>
+ <para>Cube (closed Polyhedral Surface) and Polygon Z</para>
+ <programlisting>SELECT ST_AsText(ST_3DIntersection(
+ ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
+ ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
+ ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
+ ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'),
+ 'POLYGON Z ((0 0 0, 0 0 0.5, 0 0.5 0.5, 0 0.5 0, 0 0 0))'::geometry))</programlisting>
+ <screen>TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))</screen>
- <refentry id="ST_IsPlanar">
- <refnamediv>
- <refname>ST_IsPlanar</refname>
+ <para>Intersection of 2 solids that result in volumetric intersection is also a solid (ST_Dimension returns 3)</para>
+ <programlisting>SELECT ST_AsText(ST_3DIntersection( ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1),0,0,30),
+ ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1),2,0,10) ));</programlisting>
+ <screen>POLYHEDRALSURFACE Z (((13.3333333333333 13.3333333333333 10,20 20 0,20 20 10,13.3333333333333 13.3333333333333 10)),
+ ((20 20 10,16.6666666666667 23.3333333333333 10,13.3333333333333 13.3333333333333 10,20 20 10)),
+ ((20 20 0,16.6666666666667 23.3333333333333 10,20 20 10,20 20 0)),
+ ((13.3333333333333 13.3333333333333 10,10 10 0,20 20 0,13.3333333333333 13.3333333333333 10)),
+ ((16.6666666666667 23.3333333333333 10,12 28 10,13.3333333333333 13.3333333333333 10,16.6666666666667 23.3333333333333 10)),
+ ((20 20 0,9.99999999999995 30 0,16.6666666666667 23.3333333333333 10,20 20 0)),
+ ((10 10 0,9.99999999999995 30 0,20 20 0,10 10 0)),((13.3333333333333 13.3333333333333 10,12 12 10,10 10 0,13.3333333333333 13.3333333333333 10)),
+ ((12 28 10,12 12 10,13.3333333333333 13.3333333333333 10,12 28 10)),
+ ((16.6666666666667 23.3333333333333 10,9.99999999999995 30 0,12 28 10,16.6666666666667 23.3333333333333 10)),
+ ((10 10 0,0 20 0,9.99999999999995 30 0,10 10 0)),
+ ((12 12 10,11 11 10,10 10 0,12 12 10)),((12 28 10,11 11 10,12 12 10,12 28 10)),
+ ((9.99999999999995 30 0,11 29 10,12 28 10,9.99999999999995 30 0)),((0 20 0,2 20 10,9.99999999999995 30 0,0 20 0)),
+ ((10 10 0,2 20 10,0 20 0,10 10 0)),((11 11 10,2 20 10,10 10 0,11 11 10)),((12 28 10,11 29 10,11 11 10,12 28 10)),
+ ((9.99999999999995 30 0,2 20 10,11 29 10,9.99999999999995 30 0)),((11 11 10,11 29 10,2 20 10,11 11 10)))</screen>
+
+ </refsection>
+
+ </refentry>
+
+ <refentry id="ST_3DDifference">
+ <refnamediv>
+ <refname>ST_3DDifference</refname>
- <refpurpose>Check if a surface is or not planar</refpurpose>
+ <refpurpose>Perform 3D difference</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>boolean <function>ST_IsPlanar</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <funcdef>geometry <function>ST_3DDifference</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
+ <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
-
- <para>Availability: 2.2.0: This was documented in 2.1.0 but got accidentally left out in 2.1 release.</para>
+ <para>Returns that part of geom1 that is not part of geom2.</para>
+ <para>Availability: 2.2.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- </refentry>
+ <refsection>
+ <title>Examples</title>
+ <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2;
+ </programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3ddifference01.png" />
+ </imageobject>
+ <caption><para>Original 3D geometries overlaid. geom2 is the part that will be removed.</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>SELECT ST_3DDifference(geom1,geom2)
+FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3ddifference02.png" />
+ </imageobject>
+ <caption><para>What's left after removing geom2</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+
+ </refsection>
+ <refsection>
+ <title>See Also</title>
- <refentry id="ST_Orientation">
+ <para>
+ <xref linkend="ST_Extrude" />,
+ <xref linkend="ST_AsX3D" />, <xref linkend="ST_3DIntersection" />
+ <xref linkend="ST_3DUnion" />
+ </para>
+ </refsection>
+ </refentry>
+
+ <refentry id="ST_3DUnion">
<refnamediv>
- <refname>ST_Orientation</refname>
+ <refname>ST_3DUnion</refname>
- <refpurpose>Determine surface orientation</refpurpose>
+ <refpurpose>Perform 3D union.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>integer <function>ST_Orientation</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <funcdef>geometry <function>ST_3DUnion</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
+ <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
+ </funcprototype>
+ <funcprototype>
+ <funcdef>geometry <function>ST_3DUnion</function></funcdef>
+ <paramdef><type>geometry set</type> <parameter>g1field</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -354,57 +402,178 @@ around ST_StraightSkeleton (slower case).
<refsection>
<title>Description</title>
- <para>The function only applies to polygons. It returns -1 if the polygon is counterclockwise oriented and 1 if the polygon is clockwise oriented.</para>
- <para>Availability: 2.1.0</para>
+ <para>Availability: 2.2.0</para>
+ <para>Availability: 3.3.0 aggregate variant was added</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
+ <para>&P_support;</para>
+ <para>&T_support;</para>
+
+ <para>
+ <emphasis role="bold">Aggregate variant:</emphasis>
+ returns a geometry that is the 3D union of a rowset of geometries.
+ The ST_3DUnion() function is an "aggregate"
+ function in the terminology of PostgreSQL. That means that it
+ operates on rows of data, in the same way the SUM() and AVG()
+ functions do and like most aggregates, it also ignores NULL geometries.
+ </para>
</refsection>
- </refentry>
+ <refsection>
+ <title>Examples</title>
+ <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2;
+ </programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3ddifference01.png" />
+ </imageobject>
+ <caption><para>Original 3D geometries overlaid. geom2 is the one with transparency.</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>SELECT ST_3DUnion(geom1,geom2)
+FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30) AS geom1,
+ ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
+ 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_3dunion01.png" />
+ </imageobject>
+ <caption><para>Union of geom1 and geom2</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+
+ </refsection>
+ <refsection>
+ <title>See Also</title>
- <refentry id="ST_ForceLHR">
+ <para>
+ <xref linkend="ST_Extrude" />,
+ <xref linkend="ST_AsX3D" />, <xref linkend="ST_3DIntersection" />
+ <xref linkend="ST_3DDifference" />
+ </para>
+ </refsection>
+ </refentry>
+
+ <refentry id="ST_AlphaShape">
<refnamediv>
- <refname>ST_ForceLHR</refname>
+ <refname>ST_AlphaShape</refname>
- <refpurpose>Force LHR orientation</refpurpose>
+ <refpurpose>Computes a possible concave geometry using the CGAL Alpha Shapes algorithm.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_ForceLHR</function></funcdef>
+ <funcdef>geometry <function>ST_AlphaShape</function></funcdef>
<paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <paramdef choice="opt"><type>float </type> <parameter>alpha</parameter></paramdef>
+ <paramdef choice="opt"><type>boolean </type> <parameter>allow_holes = false</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
- <title>Description</title>
+ <title>Description</title>
- <para>Availability: 2.1.0</para>
+ <para>Assume we are given a set S of points in 2D [...] and we would like to have something like "the shape formed by these points". This is quite a vague notion and there are probably many possible interpretations, the α-shape being one of them. Alpha shapes can be used for shape reconstruction from a dense unorganized set of data points. Indeed, an α-shape is demarcated by a frontier, which is a linear approximation of the original shape [1].
+ [1] F. Bernardini and C. Bajaj. Sampling and reconstructing manifolds using alpha-shapes. Technical Report CSD-TR-97-013, Dept. Comput. Sci., Purdue Univ., West Lafayette, IN, 1997.
+
+ Source: <ulink url="https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes">CGAL ALpha Shapes</ulink>
+
+ This function compute the concave hull of a set of geometry, but using CGAL and a different algorithm than ST_ConcaveHull performed by the GEOS module.
+ See : <ulink url="http://lin-ear-th-inking.blogspot.com/2022/01/concave-hulls-in-jts.html">Concave Hulls in JTS</ulink></para>
+
+ <para>Availability: 3.3.0 - requires SFCGAL >= 1.4.1.</para>
<para>&sfcgal_required;</para>
- <para>&Z_support;</para>
- <para>&P_support;</para>
- <para>&T_support;</para>
+ </refsection>
+
+ <refsection>
+ <title>Examples</title>
+<para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_alphashape01.png" />
+ </imageobject>
+ <caption><para>Concave Hull of a MultiPoint (same example As ST_OptimalAlphaShape)</para></caption>
+ </mediaobject>
+ </informalfigure>
+ <programlisting>SELECT ST_AsText(ST_AlphaShape('MULTIPOINT((94 126),(114 132),(102 110),(80 27),(136 75),(122 105),(132 44),(36 123),(48 76),(56 34),(40 81),(126 28),(112 130),(66 63),(116 100),(135 45),(54 92),(48 98),(122 70),(132 87),(102 110),(74 142),(122 90),(130 75),(117 24),(118 32),(45 33),(117 64),(39 128),(72 51),(52 52),(54 60),(46 118),(125 44),(40 126),(78 147),(108 142),(128 106),(112 126),(112 116),(122 44),(116 110),(61 63),(125 108),(34 54),(134 80),(40 86),(86 146),(40 116),(58 132),(90 122),(120 108),(81 48),(82 39),(93 33),(105 30),(114 40),(126 52),(130 63),(123 81),(125 96),(104 129),(90 135),(75 129),(64 120),(54 110),(54 102),(60 112),(36 100),(34 90),(39 66),(42 50),(60 48),(64 28),(98 24),(110 24),(57 69),(46 88),(51 129),(68 135),(96 146))'::geometry,80.2));</programlisting>
+ <screen>POLYGON((134 80,136 75,130 63,126 52,135 45,132 44,126 28,117 24,110 24,98 24,93 33,80 27,82 39,72 51,60 48,52 52,42 50,34 54,39 66,40 81,34 90,36 100,48 98,54 110,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,90 135,104 129,108 142,114 132,112 126,112 116,116 110,120 108,125 108,128 106,125 96,132 87,134 80))</screen>
+ </para>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_alphashape02.png" />
+ </imageobject>
+ <caption><para>Concave Hull of a MultiPoint, allowing holes (same example as ST_OptimalAlphaShape)</para></caption>
+ </mediaobject>
+ </informalfigure>
+ <programlisting>SELECT ST_AsText(ST_AlphaShape('MULTIPOINT((63 84),(76 88),(68 73),(53 18),(91 50),(81 70),(88 29),(24 82),(32 51),(37 23),(27 54),(84 19),(75 87),(44 42),(77 67),(90 30),(36 61),(32 65),(81 47),(88 58),(68 73),(49 95),(81 60),(87 50),
+ (78 16),(79 21),(30 22),(78 43),(26 85),(48 34),(35 35),(36 40),(31 79),(83 29),(27 84),(52 98),(72 95),(85 71),
+ (75 84),(75 77),(81 29),(77 73),(41 42),(83 72),(23 36),(89 53),(27 57),(57 97),(27 77),(39 88),(60 81),
+ (80 72),(54 32),(55 26),(62 22),(70 20),(76 27),(84 35),(87 42),(82 54),(83 64),(69 86),(60 90),(50 86),(43 80),(36 73),
+ (36 68),(40 75),(24 67),(23 60),(26 44),(28 33),(40 32),(43 19),(65 16),(73 16),(38 46),(31 59),(34 86),(45 90),(64 97))'::geometry, 100.1,true))</programlisting>
+ <screen>POLYGON((89 53,91 50,87 42,90 30,84 19,78 16,73 16,65 16,53 18,43 19,30 22,28 33,23 36,26 44,27 54,23 60,24 67,27 77,24 82,26 85,34 86,39 88,45 90,49 95,52 98,57 97,64 97,72 95,76 88,75 84,83 72,85 71,88 58,89 53),(36 61,36 68,40 75,43 80,60 81,68 73,77 67,81 60,82 54,81 47,78 43,76 27,62 22,54 32,44 42,38 46,36 61))/screen>
+ </para>
+
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_alphashape03.png" />
+ </imageobject>
+ <caption><para>Concave Hull of a MultiPoint, allowing holes (same example as ST_ConcaveHull)</para></caption>
+ </mediaobject>
+ </informalfigure>
+ <programlisting>SELECT ST_AlphaShape(
+ 'MULTIPOINT ((132 64), (114 64), (99 64), (81 64), (63 64), (57 49), (52 36), (46 20), (37 20), (26 20), (32 36), (39 55), (43 69), (50 84), (57 100), (63 118), (68 133), (74 149), (81 164), (88 180), (101 180), (112 180), (119 164), (126 149), (132 131), (139 113), (143 100), (150 84), (157 69), (163 51), (168 36), (174 20), (163 20), (150 20), (143 36), (139 49), (132 64), (99 151), (92 138), (88 124), (81 109), (74 93), (70 82), (83 82), (99 82), (112 82), (126 82), (121 96), (114 109), (110 122), (103 138), (99 151), (34 27), (43 31), (48 44), (46 58), (52 73), (63 73), (61 84), (72 71), (90 69), (101 76), (123 71), (141 62), (166 27), (150 33), (159 36), (146 44), (154 53), (152 62), (146 73), (134 76), (143 82), (141 91), (130 98), (126 104), (132 113), (128 127), (117 122), (112 133), (119 144), (108 147), (119 153), (110 171), (103 164), (92 171), (86 160), (88 142), (79 140), (72 124), (83 131), (79 118), (68 113), (63 102), (68 93), (35 45))'::geometry,102.2, t
rue);</programlisting>
+ <screen>POLYGON((134 80,136 75,130 63,135 45,132 44,126 28,117 24,110 24,98 24,80 27,82 39,72 51,60 48,56 34,52 52,42 50,
+ 34 54,39 66,40 81,34 90,36 100,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,
+ 108 142,114 132,112 126,112 116,116 110,120 108,125 108,128 106,125 96,132 87,134 80))</screen>
+ </para>
+ </refsection>
+ <refsection>
+ <title>See Also</title>
+ <para><xref linkend="ST_ConcaveHull" />, <xref linkend="ST_OptimalAlphaShape" /></para>
</refsection>
</refentry>
- <refentry id="ST_MinkowskiSum">
+ <refentry id="ST_ApproximateMedialAxis">
<refnamediv>
- <refname>ST_MinkowskiSum</refname>
+ <refname>ST_ApproximateMedialAxis</refname>
- <refpurpose>Performs Minkowski sum</refpurpose>
+ <refpurpose>Compute the approximate medial axis of an areal geometry.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_MinkowskiSum</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
+ <funcdef>geometry <function>ST_ApproximateMedialAxis</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -412,110 +581,50 @@ around ST_StraightSkeleton (slower case).
<refsection>
<title>Description</title>
- <para>This function performs a 2D minkowski sum of a point, line or polygon with a polygon.</para>
- <para>A minkowski sum of two geometries A and B is the set of all points that are the sum of any point in A and B. Minkowski sums are often used in motion planning and computer-aided design. More details on <ulink url="https://en.wikipedia.org/wiki/Minkowski_addition">Wikipedia Minkowski addition</ulink>.</para>
- <para>The first parameter can be any 2D geometry (point, linestring, polygon). If a 3D geometry is passed, it will be converted to 2D by forcing Z to 0, leading to possible cases of invalidity. The second parameter must be a 2D polygon.</para>
-
- <para>Implementation utilizes <ulink url="http://doc.cgal.org/latest/Minkowski_sum_2/">CGAL 2D Minkowskisum</ulink>.</para>
-
+ <para>
+Return an approximate medial axis for the areal input based on
+its straight skeleton. Uses an SFCGAL specific API when built against
+a capable version (1.2.0+). Otherwise the function is just a wrapper
+around ST_StraightSkeleton (slower case).
+ </para>
- <para>Availability: 2.1.0</para>
+ <para>Availability: 2.2.0</para>
<para>&sfcgal_required;</para>
+ <para>&Z_support;</para>
+ <para>&P_support;</para>
+ <para>&T_support;</para>
</refsection>
- <refsection><title>Examples</title>
- <para>Minkowski Sum of Linestring and circle polygon where Linestring cuts thru the circle</para>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_minkowskisum01.png" />
- </imageobject>
- <caption><para>Before Summing</para></caption>
- </mediaobject>
- </informalfigure>
- </para>
- </entry>
- <entry>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_minkowskisum02.png" />
- </imageobject>
- <caption><para>After summing</para></caption>
- </mediaobject>
- </informalfigure>
- </para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
- <programlisting>
-SELECT ST_MinkowskiSum(line, circle))
-FROM (SELECT
- ST_MakeLine(ST_Point(10, 10),ST_Point(100, 100)) As line,
- ST_Buffer(ST_GeomFromText('POINT(50 50)'), 30) As circle) As foo;
-
--- wkt --
-MULTIPOLYGON(((30 59.9999999999999,30.5764415879031 54.1472903395161,32.2836140246614 48.5194970290472,35.0559116309237 43.3328930094119,38.7867965644036 38.7867965644035,43.332893009412 35.0559116309236,48.5194970290474 32.2836140246614,54.1472903395162 30.5764415879031,60.0000000000001 30,65.8527096604839 30.5764415879031,71.4805029709527 32.2836140246614,76.6671069905881 35.0559116309237,81.2132034355964 38.7867965644036,171.213203435596 128.786796564404,174.944088369076 133.332893009412,177.716385975339 138.519497029047,179.423558412097 144.147290339516,180 150,179.423558412097 155.852709660484,177.716385975339 161.480502970953,174.944088369076 166.667106990588,171.213203435596 171.213203435596,166.667106990588 174.944088369076,
-161.480502970953 177.716385975339,155.852709660484 179.423558412097,150 180,144.147290339516 179.423558412097,138.519497029047 177.716385975339,133.332893009412 174.944088369076,128.786796564403 171.213203435596,38.7867965644035 81.2132034355963,35.0559116309236 76.667106990588,32.2836140246614 71.4805029709526,30.5764415879031 65.8527096604838,30 59.9999999999999)))
- </programlisting>
+ <refsection><title>Examples</title>
+ <programlisting>SELECT ST_ApproximateMedialAxis(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, 190 20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));</programlisting>
- <para>Minkowski Sum of a polygon and multipoint</para>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_minkowskisum03.png" />
- </imageobject>
- <caption><para>Before Summing</para></caption>
- </mediaobject>
- </informalfigure>
- </para>
- </entry>
- <entry>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_minkowskisum04.png" />
- </imageobject>
- <caption><para>After summing: polygon is duplicated and translated to position of points</para></caption>
- </mediaobject>
- </informalfigure>
- </para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
- <programlisting>SELECT ST_MinkowskiSum(mp, poly)
-FROM (SELECT 'MULTIPOINT(25 50,70 25)'::geometry As mp,
- 'POLYGON((130 150, 20 40, 50 60, 125 100, 130 150))'::geometry As poly
- ) As foo
+ <informaltable>
+ <tgroup cols="1">
+ <tbody>
+ <row>
+ <entry><para><informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_approximatemedialaxis01.png" />
+ </imageobject>
+ <caption><para>A polygon and its approximate medial axis</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ </refsection>
+ <refsection>
+ <title>See Also</title>
--- wkt --
-MULTIPOLYGON(
- ((70 115,100 135,175 175,225 225,70 115)),
- ((120 65,150 85,225 125,275 175,120 65))
- )
- </programlisting>
- </refsection>
+ <para><xref linkend="ST_StraightSkeleton" /></para>
+ </refsection>
</refentry>
+
<refentry id="ST_ConstrainedDelaunayTriangles">
<refnamediv>
<refname>ST_ConstrainedDelaunayTriangles</refname>
@@ -598,26 +707,29 @@ select ST_DelaunayTriangles(
</para>
</refsection>
</refentry>
- <refentry id="ST_3DIntersection">
+
+ <refentry id="ST_Extrude">
<refnamediv>
- <refname>ST_3DIntersection</refname>
+ <refname>ST_Extrude</refname>
- <refpurpose>Perform 3D intersection</refpurpose>
+ <refpurpose>Extrude a surface to a related volume</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_3DIntersection</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
+ <funcdef>geometry <function>ST_Extrude</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <paramdef><type>float</type> <parameter>x</parameter></paramdef>
+ <paramdef><type>float</type> <parameter>y</parameter></paramdef>
+ <paramdef><type>float</type> <parameter>z</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
- <para>Return a geometry that is the shared portion between geom1 and geom2.</para>
+
<para>Availability: 2.1.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
@@ -625,188 +737,143 @@ select ST_DelaunayTriangles(
<para>&T_support;</para>
</refsection>
- <refsection>
- <title>Examples</title>
- <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para>
- <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2;
- </programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3ddifference01.png" />
- </imageobject>
- <caption><para>Original 3D geometries overlaid. geom2 is shown semi-transparent</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>SELECT ST_3DIntersection(geom1,geom2)
-FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3dintersection01.png" />
- </imageobject>
- <caption><para>Intersection of geom1 and geom2</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
+ <refsection><title>Examples</title>
+ <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
- <para>3D linestrings and polygons</para>
- <programlisting> SELECT ST_AsText(ST_3DIntersection(linestring, polygon)) As wkt
-FROM ST_GeomFromText('LINESTRING Z (2 2 6,1.5 1.5 7,1 1 8,0.5 0.5 8,0 0 10)') AS linestring
- CROSS JOIN ST_GeomFromText('POLYGON((0 0 8, 0 1 8, 1 1 8, 1 0 8, 0 0 8))') AS polygon;
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30);</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_extrude01.png" />
+ </imageobject>
+ <caption><para>Original octagon formed from buffering point</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
+ 50, 'quad_segs=2'),0,0,30);</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_extrude02.png" />
+ </imageobject>
+ <caption><para>Hexagon extruded 30 units along Z produces a PolyhedralSurfaceZ</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
- wkt
---------------------------------
- LINESTRING Z (1 1 8,0.5 0.5 8)
- </programlisting>
-
- <para>Cube (closed Polyhedral Surface) and Polygon Z</para>
- <programlisting>SELECT ST_AsText(ST_3DIntersection(
- ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
- ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
- ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
- ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'),
- 'POLYGON Z ((0 0 0, 0 0 0.5, 0 0.5 0.5, 0 0.5 0, 0 0 0))'::geometry))</programlisting>
- <screen>TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))</screen>
-
- <para>Intersection of 2 solids that result in volumetric intersection is also a solid (ST_Dimension returns 3)</para>
- <programlisting>SELECT ST_AsText(ST_3DIntersection( ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1),0,0,30),
- ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1),2,0,10) ));</programlisting>
- <screen>POLYHEDRALSURFACE Z (((13.3333333333333 13.3333333333333 10,20 20 0,20 20 10,13.3333333333333 13.3333333333333 10)),
- ((20 20 10,16.6666666666667 23.3333333333333 10,13.3333333333333 13.3333333333333 10,20 20 10)),
- ((20 20 0,16.6666666666667 23.3333333333333 10,20 20 10,20 20 0)),
- ((13.3333333333333 13.3333333333333 10,10 10 0,20 20 0,13.3333333333333 13.3333333333333 10)),
- ((16.6666666666667 23.3333333333333 10,12 28 10,13.3333333333333 13.3333333333333 10,16.6666666666667 23.3333333333333 10)),
- ((20 20 0,9.99999999999995 30 0,16.6666666666667 23.3333333333333 10,20 20 0)),
- ((10 10 0,9.99999999999995 30 0,20 20 0,10 10 0)),((13.3333333333333 13.3333333333333 10,12 12 10,10 10 0,13.3333333333333 13.3333333333333 10)),
- ((12 28 10,12 12 10,13.3333333333333 13.3333333333333 10,12 28 10)),
- ((16.6666666666667 23.3333333333333 10,9.99999999999995 30 0,12 28 10,16.6666666666667 23.3333333333333 10)),
- ((10 10 0,0 20 0,9.99999999999995 30 0,10 10 0)),
- ((12 12 10,11 11 10,10 10 0,12 12 10)),((12 28 10,11 11 10,12 12 10,12 28 10)),
- ((9.99999999999995 30 0,11 29 10,12 28 10,9.99999999999995 30 0)),((0 20 0,2 20 10,9.99999999999995 30 0,0 20 0)),
- ((10 10 0,2 20 10,0 20 0,10 10 0)),((11 11 10,2 20 10,10 10 0,11 11 10)),((12 28 10,11 29 10,11 11 10,12 28 10)),
- ((9.99999999999995 30 0,2 20 10,11 29 10,9.99999999999995 30 0)),((11 11 10,11 29 10,2 20 10,11 11 10)))</screen>
-
- </refsection>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_GeomFromText('LINESTRING(50 50, 100 90, 95 150)')</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_extrude03.png" />
+ </imageobject>
+ <caption><para>Original linestring</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>SELECT ST_Extrude(
+ ST_GeomFromText('LINESTRING(50 50, 100 90, 95 150)'),0,0,10));</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_extrude04.png" />
+ </imageobject>
+ <caption><para>LineString Extruded along Z produces a PolyhedralSurfaceZ</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ </refsection>
+ <refsection>
+ <title>See Also</title>
+ <para><xref linkend="ST_AsX3D" /></para>
+ </refsection>
</refentry>
- <refentry id="ST_3DDifference">
+ <refentry id="ST_ForceLHR">
<refnamediv>
- <refname>ST_3DDifference</refname>
+ <refname>ST_ForceLHR</refname>
- <refpurpose>Perform 3D difference</refpurpose>
+ <refpurpose>Force LHR orientation</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_3DDifference</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
+ <funcdef>geometry <function>ST_ForceLHR</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
- <para>Returns that part of geom1 that is not part of geom2.</para>
- <para>Availability: 2.2.0</para>
+
+ <para>Availability: 2.1.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- <refsection>
- <title>Examples</title>
- <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para>
- <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2;
- </programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3ddifference01.png" />
- </imageobject>
- <caption><para>Original 3D geometries overlaid. geom2 is the part that will be removed.</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>SELECT ST_3DDifference(geom1,geom2)
-FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3ddifference02.png" />
- </imageobject>
- <caption><para>What's left after removing geom2</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
+ </refentry>
- </refsection>
+ <refentry id="ST_IsPlanar">
+ <refnamediv>
+ <refname>ST_IsPlanar</refname>
- <refsection>
- <title>See Also</title>
+ <refpurpose>Check if a surface is or not planar</refpurpose>
+ </refnamediv>
- <para>
- <xref linkend="ST_Extrude" />,
- <xref linkend="ST_AsX3D" />, <xref linkend="ST_3DIntersection" />
- <xref linkend="ST_3DUnion" />
- </para>
- </refsection>
- </refentry>
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>boolean <function>ST_IsPlanar</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
- <refentry id="ST_3DUnion">
+ <refsection>
+ <title>Description</title>
+
+ <para>Availability: 2.2.0: This was documented in 2.1.0 but got accidentally left out in 2.1 release.</para>
+ <para>&sfcgal_required;</para>
+ <para>&Z_support;</para>
+ <para>&P_support;</para>
+ <para>&T_support;</para>
+ </refsection>
+
+ </refentry>
+
+ <refentry id="ST_IsSolid">
<refnamediv>
- <refname>ST_3DUnion</refname>
+ <refname>ST_IsSolid</refname>
- <refpurpose>Perform 3D union.</refpurpose>
+ <refpurpose>Test if the geometry is a solid. No validity check is performed.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_3DUnion</function></funcdef>
+ <funcdef>boolean <function>ST_IsSolid</function></funcdef>
<paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
- </funcprototype>
- <funcprototype>
- <funcdef>geometry <function>ST_3DUnion</function></funcdef>
- <paramdef><type>geometry set</type> <parameter>g1field</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -814,91 +881,26 @@ FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
<refsection>
<title>Description</title>
-
<para>Availability: 2.2.0</para>
- <para>Availability: 3.3.0 aggregate variant was added</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
-
- <para>
- <emphasis role="bold">Aggregate variant:</emphasis>
- returns a geometry that is the 3D union of a rowset of geometries.
- The ST_3DUnion() function is an "aggregate"
- function in the terminology of PostgreSQL. That means that it
- operates on rows of data, in the same way the SUM() and AVG()
- functions do and like most aggregates, it also ignores NULL geometries.
- </para>
- </refsection>
-
- <refsection>
- <title>Examples</title>
- <para>3D images were generated using PostGIS <xref linkend="ST_AsX3D" /> and rendering in HTML using <ulink url="http://www.x3dom.org">X3Dom HTML Javascript rendering library</ulink>.</para>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para>
- <programlisting>SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2;
- </programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3ddifference01.png" />
- </imageobject>
- <caption><para>Original 3D geometries overlaid. geom2 is the one with transparency.</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>SELECT ST_3DUnion(geom1,geom2)
-FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
- 50, 'quad_segs=2'),0,0,30) AS geom1,
- ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
- 50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3dunion01.png" />
- </imageobject>
- <caption><para>Union of geom1 and geom2</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
-
</refsection>
- <refsection>
- <title>See Also</title>
-
- <para>
- <xref linkend="ST_Extrude" />,
- <xref linkend="ST_AsX3D" />, <xref linkend="ST_3DIntersection" />
- <xref linkend="ST_3DDifference" />
- </para>
- </refsection>
</refentry>
-
- <refentry id="ST_3DArea">
+ <refentry id="ST_MakeSolid">
<refnamediv>
- <refname>ST_3DArea</refname>
+ <refname>ST_MakeSolid</refname>
- <refpurpose>Computes area of 3D surface geometries. Will return 0 for solids.</refpurpose>
+ <refpurpose>Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a closed Polyhedral Surface or a closed TIN.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>float<function>ST_3DArea</function></funcdef>
+ <funcdef>geometry <function>ST_MakeSolid</function></funcdef>
<paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
</funcprototype>
</funcsynopsis>
@@ -907,89 +909,300 @@ FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
<refsection>
<title>Description</title>
- <para>Availability: 2.1.0</para>
+ <para>Availability: 2.2.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- <refsection><title>Examples</title>
- <para>Note: By default a PolyhedralSurface built from WKT is a surface geometry, not solid. It therefore has surface area. Once converted to a solid, no area.</para>
-<programlisting>SELECT ST_3DArea(geom) As cube_surface_area,
- ST_3DArea(ST_MakeSolid(geom)) As solid_surface_area
- FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
- ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
- ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
- ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
- ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
- ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);
-
- cube_surface_area | solid_surface_area
--------------------+--------------------
- 6 | 0 </programlisting>
-
- </refsection>
- <refsection>
- <title>See Also</title>
-
- <para><xref linkend="ST_Area" />, <xref linkend="ST_MakeSolid" />, <xref linkend="ST_IsSolid" />, <xref linkend="ST_Area" /></para>
- </refsection>
</refentry>
- <refentry id="ST_Tesselate">
+
+ <refentry id="ST_MinkowskiSum">
<refnamediv>
- <refname>ST_Tesselate</refname>
+ <refname>ST_MinkowskiSum</refname>
- <refpurpose>Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or collection of TINS</refpurpose>
+ <refpurpose>Performs Minkowski sum</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_Tesselate</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ <funcdef>geometry <function>ST_MinkowskiSum</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
+ <paramdef><type>geometry</type> <parameter>geom2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
- <para>Takes as input a surface such a MULTI(POLYGON) or POLYHEDRALSURFACE and returns a TIN representation via the process of tessellation using triangles.</para>
+
+ <para>This function performs a 2D minkowski sum of a point, line or polygon with a polygon.</para>
+ <para>A minkowski sum of two geometries A and B is the set of all points that are the sum of any point in A and B. Minkowski sums are often used in motion planning and computer-aided design. More details on <ulink url="https://en.wikipedia.org/wiki/Minkowski_addition">Wikipedia Minkowski addition</ulink>.</para>
+ <para>The first parameter can be any 2D geometry (point, linestring, polygon). If a 3D geometry is passed, it will be converted to 2D by forcing Z to 0, leading to possible cases of invalidity. The second parameter must be a 2D polygon.</para>
+
+ <para>Implementation utilizes <ulink url="http://doc.cgal.org/latest/Minkowski_sum_2/">CGAL 2D Minkowskisum</ulink>.</para>
+
+
<para>Availability: 2.1.0</para>
<para>&sfcgal_required;</para>
- <para>&Z_support;</para>
- <para>&P_support;</para>
- <para>&T_support;</para>
</refsection>
- <refsection><title>Examples</title>
- <informaltable>
- <tgroup cols="2">
- <tbody>
- <row>
- <entry><para>
- <programlisting>SELECT ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
- ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
- ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
- ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )');</programlisting>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_tesselate01.png" />
- </imageobject>
- <caption><para>Original Cube</para></caption>
- </mediaobject>
- </informalfigure></para>
- </entry>
- <entry><para>
- <programlisting>SELECT ST_Tesselate(ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
- ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
- ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
- ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));</programlisting></para>
- <para>ST_AsText output:</para>
- <screen>TIN Z (((0 0 0,0 0 1,0 1 1,0 0 0)),((0 1 0,0 0 0,0 1 1,0 1 0)),
- ((0 0 0,0 1 0,1 1 0,0 0 0)),
+ <refsection><title>Examples</title>
+ <para>Minkowski Sum of Linestring and circle polygon where Linestring cuts thru the circle</para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_minkowskisum01.png" />
+ </imageobject>
+ <caption><para>Before Summing</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_minkowskisum02.png" />
+ </imageobject>
+ <caption><para>After summing</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ <programlisting>
+SELECT ST_MinkowskiSum(line, circle))
+FROM (SELECT
+ ST_MakeLine(ST_Point(10, 10),ST_Point(100, 100)) As line,
+ ST_Buffer(ST_GeomFromText('POINT(50 50)'), 30) As circle) As foo;
+
+-- wkt --
+MULTIPOLYGON(((30 59.9999999999999,30.5764415879031 54.1472903395161,32.2836140246614 48.5194970290472,35.0559116309237 43.3328930094119,38.7867965644036 38.7867965644035,43.332893009412 35.0559116309236,48.5194970290474 32.2836140246614,54.1472903395162 30.5764415879031,60.0000000000001 30,65.8527096604839 30.5764415879031,71.4805029709527 32.2836140246614,76.6671069905881 35.0559116309237,81.2132034355964 38.7867965644036,171.213203435596 128.786796564404,174.944088369076 133.332893009412,177.716385975339 138.519497029047,179.423558412097 144.147290339516,180 150,179.423558412097 155.852709660484,177.716385975339 161.480502970953,174.944088369076 166.667106990588,171.213203435596 171.213203435596,166.667106990588 174.944088369076,
+161.480502970953 177.716385975339,155.852709660484 179.423558412097,150 180,144.147290339516 179.423558412097,138.519497029047 177.716385975339,133.332893009412 174.944088369076,128.786796564403 171.213203435596,38.7867965644035 81.2132034355963,35.0559116309236 76.667106990588,32.2836140246614 71.4805029709526,30.5764415879031 65.8527096604838,30 59.9999999999999)))
+ </programlisting>
+
+ <para>Minkowski Sum of a polygon and multipoint</para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_minkowskisum03.png" />
+ </imageobject>
+ <caption><para>Before Summing</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_minkowskisum04.png" />
+ </imageobject>
+ <caption><para>After summing: polygon is duplicated and translated to position of points</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ <programlisting>SELECT ST_MinkowskiSum(mp, poly)
+FROM (SELECT 'MULTIPOINT(25 50,70 25)'::geometry As mp,
+ 'POLYGON((130 150, 20 40, 50 60, 125 100, 130 150))'::geometry As poly
+ ) As foo
+
+
+-- wkt --
+MULTIPOLYGON(
+ ((70 115,100 135,175 175,225 225,70 115)),
+ ((120 65,150 85,225 125,275 175,120 65))
+ )
+ </programlisting>
+ </refsection>
+
+ </refentry>
+
+ <refentry id="ST_OptimalAlphaShape">
+ <refnamediv>
+ <refname>ST_OptimalAlphaShape</refname>
+
+ <refpurpose>Computes a possible concave geometry using the CGAL Alpha Shapes algorithm after have computed the "optimal" alpha value.</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>geometry<function>ST_OptimalAlphaShape</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>param_geom</parameter></paramdef>
+ <paramdef choice="opt"><type>boolean </type> <parameter>allow_holes = false</parameter></paramdef>
+ <paramdef choice="opt"><type>integer </type> <parameter>nb_components</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsection>
+ <title>Description</title>
+
+ <para>Computes the "optimal" alpha-shapes of the set of geometry.
+
+ CGAL can automatically find the optimal value of alpha. This version uses it to find an "optimal" alpha-shape.
+ The result is a single polygon. It will not contain holes unless the optional <varname>param_allow_holes</varname> argument is specified as true.
+
+ The result will be generated such that the number of solid component of the alpha shape is equal to or smaller than <varname>param_nb_components</varname>.</para>
+
+ <para>Availability: 3.3.0 - requires SFCGAL >= 1.4.1.</para>
+ <para>&sfcgal_required;</para>
+ </refsection>
+
+ <refsection>
+ <title>Examples</title>
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_optimalalphashape01.png" />
+ </imageobject>
+ <caption><para>Concave Hull of a MultiPoint (same example as ST_AlphaShape)</para></caption>
+ </mediaobject>
+ </informalfigure>
+ <programlisting>SELECT ST_AsText(ST_OptimalAlphaShape('MULTIPOINT((63 84),(76 88),(68 73),(53 18),(91 50),(81 70),
+ (88 29),(24 82),(32 51),(37 23),(27 54),(84 19),(75 87),(44 42),(77 67),(90 30),(36 61),(32 65),
+ (81 47),(88 58),(68 73),(49 95),(81 60),(87 50),
+ (78 16),(79 21),(30 22),(78 43),(26 85),(48 34),(35 35),(36 40),(31 79),(83 29),(27 84),(52 98),(72 95),(85 71),
+ (75 84),(75 77),(81 29),(77 73),(41 42),(83 72),(23 36),(89 53),(27 57),(57 97),(27 77),(39 88),(60 81),
+ (80 72),(54 32),(55 26),(62 22),(70 20),(76 27),(84 35),(87 42),(82 54),(83 64),(69 86),(60 90),(50 86),(43 80),(36 73),
+ (36 68),(40 75),(24 67),(23 60),(26 44),(28 33),(40 32),(43 19),(65 16),(73 16),(38 46),(31 59),(34 86),(45 90),(64 97))'::geometry));</programlisting>
+ <screen>POLYGON((89 53,91 50,87 42,90 30,88 29,84 19,78 16,73 16,65 16,53 18,43 19,37 23,30 22,28 33,23 36,
+ 26 44,27 54,23 60,24 67,27 77,24 82,26 85,34 86,39 88,45 90,49 95,52 98,57 97,64 97,72 95,76 88,75 84,75 77,83 72,85 71,83 64,88 58,89 53))</screen>
+ </para>
+
+ <para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_optimalalphashape02.png" />
+ </imageobject>
+ <caption><para>Concave Hull of a MultiPoint, allowing holes (same example as ST_AlphaShape)</para></caption>
+ </mediaobject>
+ </informalfigure>
+ <programlisting>SELECT ST_AsText(ST_OptimalAlphaShape('MULTIPOINT((63 84),(76 88),(68 73),(53 18),(91 50),(81 70),(88 29),(24 82),(32 51),(37 23),(27 54),(84 19),(75 87),(44 42),(77 67),(90 30),(36 61),(32 65),(81 47),(88 58),(68 73),(49 95),(81 60),(87 50),
+ (78 16),(79 21),(30 22),(78 43),(26 85),(48 34),(35 35),(36 40),(31 79),(83 29),(27 84),(52 98),(72 95),(85 71),
+ (75 84),(75 77),(81 29),(77 73),(41 42),(83 72),(23 36),(89 53),(27 57),(57 97),(27 77),(39 88),(60 81),
+ (80 72),(54 32),(55 26),(62 22),(70 20),(76 27),(84 35),(87 42),(82 54),(83 64),(69 86),(60 90),(50 86),(43 80),(36 73),
+ (36 68),(40 75),(24 67),(23 60),(26 44),(28 33),(40 32),(43 19),(65 16),(73 16),(38 46),(31 59),(34 86),(45 90),(64 97))'::geometry, allow_holes => true));</programlisting>
+ <screen>POLYGON((89 53,91 50,87 42,90 30,88 29,84 19,78 16,73 16,65 16,53 18,43 19,37 23,30 22,28 33,23 36,26 44,27 54,23 60,24 67,27 77,24 82,26 85,34 86,39 88,45 90,49 95,52 98,57 97,64 97,72 95,76 88,75 84,75 77,83 72,85 71,83 64,88 58,89 53),(36 61,36 68,40 75,43 80,50 86,60 81,68 73,77 67,81 60,82 54,81 47,78 43,81 29,76 27,70 20,62 22,55 26,54 32,48 34,44 42,38 46,36 61))</screen>
+ </para>
+ </refsection>
+ <refsection>
+ <title>See Also</title>
+ <para><xref linkend="ST_ConcaveHull" />, <xref linkend="ST_AlphaShape" /></para>
+ </refsection>
+
+ </refentry>
+
+ <refentry id="ST_Orientation">
+ <refnamediv>
+ <refname>ST_Orientation</refname>
+
+ <refpurpose>Determine surface orientation</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>integer <function>ST_Orientation</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsection>
+ <title>Description</title>
+
+ <para>The function only applies to polygons. It returns -1 if the polygon is counterclockwise oriented and 1 if the polygon is clockwise oriented.</para>
+
+ <para>Availability: 2.1.0</para>
+ <para>&sfcgal_required;</para>
+ <para>&Z_support;</para>
+ </refsection>
+
+ </refentry>
+
+ <refentry id="ST_Tesselate">
+ <refnamediv>
+ <refname>ST_Tesselate</refname>
+
+ <refpurpose>Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or collection of TINS</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>geometry <function>ST_Tesselate</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsection>
+ <title>Description</title>
+ <para>Takes as input a surface such a MULTI(POLYGON) or POLYHEDRALSURFACE and returns a TIN representation via the process of tessellation using triangles.</para>
+ <para>Availability: 2.1.0</para>
+ <para>&sfcgal_required;</para>
+ <para>&Z_support;</para>
+ <para>&P_support;</para>
+ <para>&T_support;</para>
+ </refsection>
+
+ <refsection><title>Examples</title>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <programlisting>SELECT ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
+ ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
+ ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
+ ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )');</programlisting>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_tesselate01.png" />
+ </imageobject>
+ <caption><para>Original Cube</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para>
+ <programlisting>SELECT ST_Tesselate(ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
+ ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
+ ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
+ ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));</programlisting></para>
+ <para>ST_AsText output:</para>
+ <screen>TIN Z (((0 0 0,0 0 1,0 1 1,0 0 0)),((0 1 0,0 0 0,0 1 1,0 1 0)),
+ ((0 0 0,0 1 0,1 1 0,0 0 0)),
((1 0 0,0 0 0,1 1 0,1 0 0)),((0 0 1,1 0 0,1 0 1,0 0 1)),
((0 0 1,0 0 0,1 0 0,0 0 1)),
((1 1 0,1 1 1,1 0 1,1 1 0)),((1 0 0,1 1 0,1 0 1,1 0 0)),
@@ -1103,75 +1316,18 @@ FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
</refentry>
- <refentry id="ST_MakeSolid">
- <refnamediv>
- <refname>ST_MakeSolid</refname>
-
- <refpurpose>Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a closed Polyhedral Surface or a closed TIN.</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>geometry<function>ST_MakeSolid</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsection>
- <title>Description</title>
-
- <para>Availability: 2.2.0</para>
- <para>&sfcgal_required;</para>
- <para>&Z_support;</para>
- <para>&P_support;</para>
- <para>&T_support;</para>
- </refsection>
-
- </refentry>
-
- <refentry id="ST_IsSolid">
- <refnamediv>
- <refname>ST_IsSolid</refname>
-
- <refpurpose>Test if the geometry is a solid. No validity check is performed.</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>boolean<function>ST_IsSolid</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsection>
- <title>Description</title>
-
- <para>Availability: 2.2.0</para>
- <para>&sfcgal_required;</para>
- <para>&Z_support;</para>
- <para>&P_support;</para>
- <para>&T_support;</para>
- </refsection>
-
- </refentry>
-
-
- <refentry id="ST_3DConvexHull">
+ <refentry id="ST_StraightSkeleton">
<refnamediv>
- <refname>ST_3DConvexHull</refname>
+ <refname>ST_StraightSkeleton</refname>
- <refpurpose>Computes the 3D convex hull of a geometry.</refpurpose>
+ <refpurpose>Compute a straight skeleton from a geometry</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
- <funcdef>geometry <function>ST_3DConvexHull</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom1</parameter></paramdef>
+ <funcdef>geometry <function>ST_StraightSkeleton</function></funcdef>
+ <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
@@ -1179,208 +1335,44 @@ FROM ( SELECT ST_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
<refsection>
<title>Description</title>
- <para>Availability: 3.3.0</para>
+ <para>Availability: 2.1.0</para>
<para>&sfcgal_required;</para>
<para>&Z_support;</para>
<para>&P_support;</para>
<para>&T_support;</para>
</refsection>
- <refsection>
- <title>Examples</title>
- <programlisting>SELECT ST_AsText(ST_3DConvexHull('LINESTRING Z(0 0 5, 1 5 3, 5 7 6, 9 5 3 , 5 7 5, 6 3 5)'::geometry));</programlisting>
- <screen>POLYHEDRALSURFACE Z (((1 5 3,9 5 3,0 0 5,1 5 3)),((1 5 3,0 0 5,5 7 6,1 5 3)),((5 7 6,5 7 5,1 5 3,5 7 6)),((0 0 5,6 3 5,5 7 6,0 0 5)),((6 3 5,9 5 3,5 7 6,6 3 5)),((0 0 5,9 5 3,6 3 5,0 0 5)),((9 5 3,5 7 5,5 7 6,9 5 3)),((1 5 3,5 7 5,9 5 3,1 5 3)))</screen>
-
- <programlisting>WITH f AS (SELECT i, ST_Extrude(geom, 0,0, i ) AS geom
-FROM ST_Subdivide(ST_Letters('CH'),5) WITH ORDINALITY AS sd(geom,i)
- )
- SELECT ST_3DConvexHull(ST_Collect(f.geom) )
- FROM f;</programlisting>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_3dconvexhull.png" />
- </imageobject>
- <caption><para>Original geometry overlaid with 3D convex hull</para></caption>
- </mediaobject>
- </informalfigure>
- </para>
- </refsection>
- <refsection>
- <title>See Also</title>
- <para><xref linkend="ST_Letters" />, <xref linkend="ST_AsX3D" /></para>
- </refsection>
-
- </refentry>
-
- <refentry id="ST_AlphaShape">
- <refnamediv>
- <refname>ST_AlphaShape</refname>
-
- <refpurpose>Computes a possible concave geometry using the CGAL Alpha Shapes algorithm.</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>geometry <function>ST_AlphaShape</function></funcdef>
- <paramdef><type>geometry</type> <parameter>geom</parameter></paramdef>
- <paramdef choice="opt"><type>float </type> <parameter>alpha</parameter></paramdef>
- <paramdef choice="opt"><type>boolean </type> <parameter>allow_holes = false</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsection>
- <title>Description</title>
-
- <para>Assume we are given a set S of points in 2D [...] and we would like to have something like "the shape formed by these points". This is quite a vague notion and there are probably many possible interpretations, the α-shape being one of them. Alpha shapes can be used for shape reconstruction from a dense unorganized set of data points. Indeed, an α-shape is demarcated by a frontier, which is a linear approximation of the original shape [1].
- [1] F. Bernardini and C. Bajaj. Sampling and reconstructing manifolds using alpha-shapes. Technical Report CSD-TR-97-013, Dept. Comput. Sci., Purdue Univ., West Lafayette, IN, 1997.
-
- Source: <ulink url="https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes">CGAL ALpha Shapes</ulink>
-
- This function compute the concave hull of a set of geometry, but using CGAL and a different algorithm than ST_ConcaveHull performed by the GEOS module.
- See : <ulink url="http://lin-ear-th-inking.blogspot.com/2022/01/concave-hulls-in-jts.html">Concave Hulls in JTS</ulink></para>
-
- <para>Availability: 3.3.0 - requires SFCGAL >= 1.4.1.</para>
- <para>&sfcgal_required;</para>
- </refsection>
-
- <refsection>
- <title>Examples</title>
-<para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_alphashape01.png" />
- </imageobject>
- <caption><para>Concave Hull of a MultiPoint</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>SELECT ST_AsText(ST_AlphaShape('MULTIPOINT((94 126),(114 132),(102 110),(80 27),(136 75),(122 105),(132 44),(36 123),(48 76),(56 34),(40 81),(126 28),(112 130),(66 63),(116 100),(135 45),(54 92),(48 98),(122 70),(132 87),(102 110),(74 142),(122 90),(130 75),(117 24),(118 32),(45 33),(117 64),(39 128),(72 51),(52 52),(54 60),(46 118),(125 44),(40 126),(78 147),(108 142),(128 106),(112 126),(112 116),(122 44),(116 110),(61 63),(125 108),(34 54),(134 80),(40 86),(86 146),(40 116),(58 132),(90 122),(120 108),(81 48),(82 39),(93 33),(105 30),(114 40),(126 52),(130 63),(123 81),(125 96),(104 129),(90 135),(75 129),(64 120),(54 110),(54 102),(60 112),(36 100),(34 90),(39 66),(42 50),(60 48),(64 28),(98 24),(110 24),(57 69),(46 88),(51 129),(68 135),(96 146))'::geometry,80.2));</programlisting>
- <screen>POLYGON((134 80,136 75,130 63,126 52,135 45,132 44,126 28,117 24,110 24,98 24,93 33,80 27,82 39,72 51,60 48,52 52,42 50,34 54,39 66,40 81,34 90,36 100,48 98,54 110,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,90 135,104 129,108 142,114 132,112 126,112 116,116 110,120 108,125 108,128 106,125 96,132 87,134 80))</screen>
- </para>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_alphashape02.png" />
- </imageobject>
- <caption><para>Concave Hull of a MultiPoint, allowing holes (same example as ST_OptimalAlphaShape)</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>SELECT ST_AsText(ST_AlphaShape('MULTIPOINT((63 84),(76 88),(68 73),(53 18),(91 50),(81 70),(88 29),(24 82),(32 51),
- (37 23),(27 54),(84 19),(75 87),(44 42),(77 67),(90 30),(36 61),(32 65),(81 47),(88 58),(68 73),(49 95),(81 60),(87 50),(78 16),
- (79 21),(30 22),(78 43),(26 85),(48 34),(35 35),(36 40),(31 79),(83 29),(27 84),(52 98),(72 95),(85 71),(75 84),(75 77),(81 29),
- (77 73),(41 42),(83 72),(23 36),(89 53),(27 57),(57 97),(27 77),(39 88),(60 81),(80 72),(54 32),(55 26),(62 22),(70 20),(76 27),
- (84 35),(87 42),(82 54),(83 64),(69 86),(60 90),(50 86),(43 80),(36 73),(36 68),(40 75),(24 67),(23 60),(26 44),(28 33),(40 32),
- (43 19),(65 16),(73 16),(38 46),(31 59),(34 86),(45 90),(64 97))'::geometry, 100.1,true))</programlisting>
- <screen>POLYGON((89 53,91 50,87 42,90 30,84 19,78 16,73 16,65 16,53 18,43 19,30 22,28 33,23 36,26 44,27 54,
- 23 60,24 67,27 77,24 82,26 85,34 86,39 88,45 90,49 95,52 98,57 97,64 97,72 95,76 88,75 84,83 72,85 71,88 58,89 53),
- (36 61,36 68,40 75,43 80,60 81,68 73,77 67,81 60,82 54,81 47,78 43,76 27,62 22,54 32,44 42,38 46,36 61))</screen>
- </para>
+ <refsection><title>Examples</title>
+ <programlisting>SELECT ST_StraightSkeleton(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, 190 20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));</programlisting>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_alphashape03.png" />
- </imageobject>
- <caption><para>Concave Hull of a MultiPoint, allowing holes (same example as ST_ConcaveHull)</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>SELECT ST_AlphaShape(
- 'MULTIPOINT ((132 64), (114 64), (99 64), (81 64), (63 64), (57 49), (52 36), (46 20), (37 20), (26 20), (32 36), (39 55), (43 69), (50 84), (57 100), (63 118), (68 133), (74 149), (81 164), (88 180), (101 180), (112 180), (119 164), (126 149), (132 131), (139 113), (143 100), (150 84), (157 69), (163 51), (168 36), (174 20), (163 20), (150 20), (143 36), (139 49), (132 64), (99 151), (92 138), (88 124), (81 109), (74 93), (70 82), (83 82), (99 82), (112 82), (126 82), (121 96), (114 109), (110 122), (103 138), (99 151), (34 27), (43 31), (48 44), (46 58), (52 73), (63 73), (61 84), (72 71), (90 69), (101 76), (123 71), (141 62), (166 27), (150 33), (159 36), (146 44), (154 53), (152 62), (146 73), (134 76), (143 82), (141 91), (130 98), (126 104), (132 113), (128 127), (117 122), (112 133), (119 144), (108 147), (119 153), (110 171), (103 164), (92 171), (86 160), (88 142), (79 140), (72 124), (83 131), (79 118), (68 113), (63 102), (68 93), (35 45))'::geometry,102.2, t
rue);</programlisting>
- <screen>POLYGON((134 80,136 75,130 63,135 45,132 44,126 28,117 24,110 24,98 24,80 27,82 39,72 51,60 48,56 34,52 52,42 50,
- 34 54,39 66,40 81,34 90,36 100,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,
- 108 142,114 132,112 126,112 116,116 110,120 108,125 108,128 106,125 96,132 87,134 80))</screen>
- </para>
- </refsection>
- <refsection>
- <title>See Also</title>
- <para><xref linkend="ST_ConcaveHull" />, <xref linkend="ST_OptimalAlphaShape" /></para>
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para><informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_straightskeleton01.png" />
+ </imageobject>
+ <caption><para>Original polygon</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ <entry><para><informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_straightskeleton02.png" />
+ </imageobject>
+ <caption><para>Straight Skeleton of polygon</para></caption>
+ </mediaobject>
+ </informalfigure></para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
</refsection>
</refentry>
- <refentry id="ST_OptimalAlphaShape">
- <refnamediv>
- <refname>ST_OptimalAlphaShape</refname>
-
- <refpurpose>Computes a possible concave geometry using the CGAL Alpha Shapes algorithm after have computed the "optimal" alpha value.</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>geometry<function>ST_OptimalAlphaShape</function></funcdef>
- <paramdef><type>geometry</type> <parameter>param_geom</parameter></paramdef>
- <paramdef choice="opt"><type>boolean </type> <parameter>allow_holes = false</parameter></paramdef>
- <paramdef choice="opt"><type>integer </type> <parameter>nb_components</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsection>
- <title>Description</title>
-
- <para>Computes the "optimal" alpha-shapes of the set of geometry.
-
- CGAL can automatically find the optimal value of alpha. This version uses it to find an "optimal" alpha-shape.
- The result is a single polygon. It will not contain holes unless the optional <varname>param_allow_holes</varname> argument is specified as true.
-
- The result will be generated such that the number of solid component of the alpha shape is equal to or smaller than <varname>param_nb_components</varname>.</para>
-
- <para>Availability: 3.3.0 - requires SFCGAL >= 1.4.1.</para>
- <para>&sfcgal_required;</para>
- </refsection>
-
- <refsection>
- <title>Examples</title>
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_optimalalphashape01.png" />
- </imageobject>
- <caption><para>Concave Hull of a MultiPoint</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>SELECT ST_AsText(ST_OptimalAlphaShape('MULTIPOINT((94 126),(114 132),(102 110),(80 27),
- (136 75),(122 105),(132 44),(36 123),(48 76),(56 34),(40 81),(126 28),(112 130),(66 63),(116 100),(135 45),
- (54 92),(48 98),(122 70),(132 87),(102 110),(74 142),(122 90),(130 75),(117 24),(118 32),(45 33),(117 64),
- (39 128),(72 51),(52 52),(54 60),(46 118),(125 44),(40 126),(78 147),(108 142),(128 106),(112 126),(112 116),
- (122 44),(116 110),(61 63),(125 108),(34 54),(134 80),(40 86),(86 146),(40 116),(58 132),(90 122),(120 108),
- (81 48),(82 39),(93 33),(105 30),(114 40),(126 52),(130 63),(123 81),(125 96),(104 129),(90 135),(75 129),
- (64 120),(54 110),(54 102),(60 112),(36 100),(34 90),(39 66),(42 50),(60 48),(64 28),(98 24),(110 24),(57 69),
- (46 88),(51 129),(68 135),(96 146))'::geometry));</programlisting>
- <screen>POLYGON((134 80,136 75,130 63,135 45,132 44,126 28,117 24,110 24,98 24,80 27,64 28,56 34,45 33,42 50,34 54,
- 39 66,40 81,34 90,36 100,40 116,36 123,39 128,51 129,58 132,68 135,74 142,78 147,86 146,96 146,108 142,
- 114 132,112 126,112 116,125 108,128 106,125 96,132 87,134 80))</screen>
- </para>
-
- <para>
- <informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_optimalalphashape02.png" />
- </imageobject>
- <caption><para>Concave Hull of a MultiPoint, allowing holes</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>SELECT ST_AsText(ST_OptimalAlphaShape('MULTIPOINT((63 84),(76 88),(68 73),(53 18),(91 50),(81 70),(88 29),(24 82),(32 51),(37 23),(27 54),(84 19),(75 87),(44 42),(77 67),(90 30),(36 61),(32 65),(81 47),(88 58),(68 73),(49 95),(81 60),(87 50),
- (78 16),(79 21),(30 22),(78 43),(26 85),(48 34),(35 35),(36 40),(31 79),(83 29),(27 84),(52 98),(72 95),(85 71),
- (75 84),(75 77),(81 29),(77 73),(41 42),(83 72),(23 36),(89 53),(27 57),(57 97),(27 77),(39 88),(60 81),
- (80 72),(54 32),(55 26),(62 22),(70 20),(76 27),(84 35),(87 42),(82 54),(83 64),(69 86),(60 90),(50 86),(43 80),(36 73),
- (36 68),(40 75),(24 67),(23 60),(26 44),(28 33),(40 32),(43 19),(65 16),(73 16),(38 46),(31 59),(34 86),(45 90),(64 97))'::geometry, allow_holes => true));</programlisting>
- <screen>POLYGON((89 53,91 50,87 42,90 30,88 29,84 19,78 16,73 16,65 16,53 18,43 19,37 23,30 22,28 33,23 36,26 44,27 54,23 60,24 67,27 77,24 82,26 85,34 86,39 88,45 90,49 95,52 98,57 97,64 97,72 95,76 88,75 84,75 77,83 72,85 71,83 64,88 58,89 53),(36 61,36 68,40 75,43 80,50 86,60 81,68 73,77 67,81 60,82 54,81 47,78 43,81 29,76 27,70 20,62 22,55 26,54 32,48 34,44 42,38 46,36 61))</screen>
- </para>
- </refsection>
- <refsection>
- <title>See Also</title>
- <para><xref linkend="ST_ConcaveHull" />, <xref linkend="ST_AlphaShape" /></para>
- </refsection>
-
- </refentry>
</sect1>
-----------------------------------------------------------------------
Summary of changes:
doc/html/image_src/st_alphashape01.wkt | 4 +-
doc/reference_sfcgal.xml | 1606 ++++++++++++++++----------------
2 files changed, 801 insertions(+), 809 deletions(-)
hooks/post-receive
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