[postgis-tickets] [SCM] PostGIS branch master updated. 3.4.0beta1-27-gfa5525813
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Tue Jul 18 17:05:13 PDT 2023
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- Log -----------------------------------------------------------------
commit fa5525813fade6d6a3c21a849ea4d6552780e3c4
Author: Martin Davis <mtnclimb at gmail.com>
Date: Tue Jul 18 17:05:06 2023 -0700
Improve doc for ST_BuildArea
diff --git a/doc/html/images/Makefile.in b/doc/html/images/Makefile.in
index 871d7fcd9..8a268e0e6 100644
--- a/doc/html/images/Makefile.in
+++ b/doc/html/images/Makefile.in
@@ -61,6 +61,8 @@ GENERATED_IMAGES= \
st_buffer12.png \
st_buffer13.png \
st_buildarea01.png \
+ st_buildarea02.png \
+ st_buildarea03.png \
st_closestpoint01.png \
st_closestpoint02.png \
st_clusterkmeans02.png \
diff --git a/doc/html/images/wkt/st_buildarea02.wkt b/doc/html/images/wkt/st_buildarea02.wkt
new file mode 100644
index 000000000..f2522563d
--- /dev/null
+++ b/doc/html/images/wkt/st_buildarea02.wkt
@@ -0,0 +1 @@
+ArgA-endpoints;MULTILINESTRING ((180 40, 30 20, 20 90), (180 40, 160 160), (160 160, 80 190, 80 120, 20 90), (80 60, 120 130, 150 80), (80 60, 150 80))
diff --git a/doc/html/images/wkt/st_buildarea03.wkt b/doc/html/images/wkt/st_buildarea03.wkt
new file mode 100644
index 000000000..4e56f0dab
--- /dev/null
+++ b/doc/html/images/wkt/st_buildarea03.wkt
@@ -0,0 +1 @@
+Result;POLYGON ((180 40, 30 20, 20 90, 80 120, 80 190, 160 160, 180 40), (150 80, 120 130, 80 60, 150 80))
diff --git a/doc/reference_processing.xml b/doc/reference_processing.xml
index 1cab2944d..3f266142a 100644
--- a/doc/reference_processing.xml
+++ b/doc/reference_processing.xml
@@ -403,10 +403,20 @@ POLYGON((236057.59057465 900908.759918696,236028.301252769 900838.049240578,235
The result is a Polygon or MultiPolygon, depending on input.
If the input linework does not form polygons, NULL is returned.
</para>
- <para>This function assumes all inner geometries represent holes</para>
+ <para>Unlike <xref linkend="ST_MakePolygon" />,
+ this function accepts rings formed by multiple lines, and can form any number of polygons.
+ </para>
+ <para>This function assumes all inner geometries represent holes.
+ To turn inner geometries into polygons as well, see <xref linkend="ST_Polygonize" />.
+ </para>
<note>
- <para>Input linework must be correctly noded for this function to work properly</para>
+ <para>Input linework must be correctly noded for this function to work properly.
+ <xref linkend="ST_Node" /> can be used to node lines.
+ </para>
+ <para>If the input linework crosses, this function will produce invalid polygons.
+ <xref linkend="ST_MakeValid" /> can be used to ensure the output is valid.
+ </para>
</note>
<para role="availability" conformance="1.1.0">Availability: 1.1.0</para>
@@ -414,48 +424,77 @@ POLYGON((236057.59057465 900908.759918696,236028.301252769 900838.049240578,235
<refsection>
<title>Examples</title>
- <informaltable>
- <tgroup cols="1">
- <tbody>
- <row>
- <entry><para><informalfigure>
- <mediaobject>
- <imageobject>
- <imagedata fileref="images/st_buildarea01.png" />
- </imageobject>
- <caption><para>These will create a donut</para></caption>
- </mediaobject>
- </informalfigure>
- <programlisting>
-<lineannotation>using polygons</lineannotation>
+
+ <informaltable>
+ <tgroup cols="2">
+ <tbody>
+ <row>
+ <entry><para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_buildarea02.png" />
+ </imageobject>
+ <caption><para>Input lines</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para></entry>
+ <entry><para>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_buildarea03.png" />
+ </imageobject>
+ <caption><para>Area result</para></caption>
+ </mediaobject>
+ </informalfigure>
+ </para></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+
+ <programlisting>WITH data(geom) AS (VALUES
+ ('LINESTRING (180 40, 30 20, 20 90)'::geometry)
+ ,('LINESTRING (180 40, 160 160)'::geometry)
+ ,('LINESTRING (160 160, 80 190, 80 120, 20 90)'::geometry)
+ ,('LINESTRING (80 60, 120 130, 150 80)'::geometry)
+ ,('LINESTRING (80 60, 150 80)'::geometry)
+)
+SELECT ST_AsText( ST_BuildArea( ST_Collect( geom )))
+ FROM data;
+
+ ------------------------------------------------------------------------------------------
+ POLYGON((180 40,30 20,20 90,80 120,80 190,160 160,180 40),(150 80,120 130,80 60,150 80))
+</programlisting>
+
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="images/st_buildarea01.png" />
+ </imageobject>
+ <caption><para>Create a donut from two circular polygons</para></caption>
+ </mediaobject>
+ </informalfigure>
+<programlisting>
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;
- </programlisting>
+</programlisting>
- <programlisting>
-<lineannotation>using linestrings</lineannotation>
-SELECT ST_BuildArea(ST_Collect(smallc,bigc))
-FROM (SELECT
- ST_ExteriorRing(ST_Buffer(
- ST_GeomFromText('POINT(100 90)'), 25)) As smallc,
- ST_ExteriorRing(ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50)) As bigc) As foo;</programlisting>
- </para></entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
</refsection>
<refsection>
<title>See Also</title>
<para>
- <xref linkend="ST_Node" />,
+ <xref linkend="ST_Collect" />,
<xref linkend="ST_MakePolygon" />,
<xref linkend="ST_MakeValid" />,
+ <xref linkend="ST_Node" />,
+ <xref linkend="ST_Polygonize" />,
<xref linkend="ST_BdPolyFromText" />,
<xref linkend="ST_BdMPolyFromText" /> (wrappers to
this function with standard OGC interface)</para>
-----------------------------------------------------------------------
Summary of changes:
doc/html/images/Makefile.in | 2 +
doc/html/images/wkt/st_buildarea02.wkt | 1 +
doc/html/images/wkt/st_buildarea03.wkt | 1 +
doc/reference_processing.xml | 99 +++++++++++++++++++++++-----------
4 files changed, 73 insertions(+), 30 deletions(-)
create mode 100644 doc/html/images/wkt/st_buildarea02.wkt
create mode 100644 doc/html/images/wkt/st_buildarea03.wkt
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