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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:17:33 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:17:33 +0000
commit5e45211a64149b3c659b90ff2de6fa982a5a93ed (patch)
tree739caf8c461053357daa9f162bef34516c7bf452 /doc/src/sgml/html/functions-geometry.html
parentInitial commit. (diff)
downloadpostgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.tar.xz
postgresql-15-5e45211a64149b3c659b90ff2de6fa982a5a93ed.zip
Adding upstream version 15.5.upstream/15.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>9.11. Geometric Functions and Operators</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="functions-enum.html" title="9.10. Enum Support Functions" /><link rel="next" href="functions-net.html" title="9.12. Network Address Functions and Operators" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">9.11. Geometric Functions and Operators</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="functions-enum.html" title="9.10. Enum Support Functions">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><th width="60%" align="center">Chapter 9. Functions and Operators</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="functions-net.html" title="9.12. Network Address Functions and Operators">Next</a></td></tr></table><hr /></div><div class="sect1" id="FUNCTIONS-GEOMETRY"><div class="titlepage"><div><div><h2 class="title" style="clear: both">9.11. Geometric Functions and Operators</h2></div></div></div><p>
+ The geometric types <code class="type">point</code>, <code class="type">box</code>,
+ <code class="type">lseg</code>, <code class="type">line</code>, <code class="type">path</code>,
+ <code class="type">polygon</code>, and <code class="type">circle</code> have a large set of
+ native support functions and operators, shown in <a class="xref" href="functions-geometry.html#FUNCTIONS-GEOMETRY-OP-TABLE" title="Table 9.36. Geometric Operators">Table 9.36</a>, <a class="xref" href="functions-geometry.html#FUNCTIONS-GEOMETRY-FUNC-TABLE" title="Table 9.37. Geometric Functions">Table 9.37</a>, and <a class="xref" href="functions-geometry.html#FUNCTIONS-GEOMETRY-CONV-TABLE" title="Table 9.38. Geometric Type Conversion Functions">Table 9.38</a>.
+ </p><div class="table" id="FUNCTIONS-GEOMETRY-OP-TABLE"><p class="title"><strong>Table 9.36. Geometric Operators</strong></p><div class="table-contents"><table class="table" summary="Geometric Operators" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature">
+ Operator
+ </p>
+ <p>
+ Description
+ </p>
+ <p>
+ Example(s)
+ </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">+</code> <code class="type">point</code>
+ → <code class="returnvalue"><em class="replaceable"><code>geometric_type</code></em></code>
+ </p>
+ <p>
+ Adds the coordinates of the second <code class="type">point</code> to those of each
+ point of the first argument, thus performing translation.
+ Available for <code class="type">point</code>, <code class="type">box</code>, <code class="type">path</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(1,1),(0,0)' + point '(2,0)'</code>
+ → <code class="returnvalue">(3,1),(2,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">path</code> <code class="literal">+</code> <code class="type">path</code>
+ → <code class="returnvalue">path</code>
+ </p>
+ <p>
+ Concatenates two open paths (returns NULL if either path is closed).
+ </p>
+ <p>
+ <code class="literal">path '[(0,0),(1,1)]' + path '[(2,2),(3,3),(4,4)]'</code>
+ → <code class="returnvalue">[(0,0),(1,1),(2,2),(3,3),(4,4)]</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">-</code> <code class="type">point</code>
+ → <code class="returnvalue"><em class="replaceable"><code>geometric_type</code></em></code>
+ </p>
+ <p>
+ Subtracts the coordinates of the second <code class="type">point</code> from those
+ of each point of the first argument, thus performing translation.
+ Available for <code class="type">point</code>, <code class="type">box</code>, <code class="type">path</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(1,1),(0,0)' - point '(2,0)'</code>
+ → <code class="returnvalue">(-1,1),(-2,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">*</code> <code class="type">point</code>
+ → <code class="returnvalue"><em class="replaceable"><code>geometric_type</code></em></code>
+ </p>
+ <p>
+ Multiplies each point of the first argument by the second
+ <code class="type">point</code> (treating a point as being a complex number
+ represented by real and imaginary parts, and performing standard
+ complex multiplication). If one interprets
+ the second <code class="type">point</code> as a vector, this is equivalent to
+ scaling the object's size and distance from the origin by the length
+ of the vector, and rotating it counterclockwise around the origin by
+ the vector's angle from the <em class="replaceable"><code>x</code></em> axis.
+ Available for <code class="type">point</code>, <code class="type">box</code>,<a href="#ftn.FUNCTIONS-GEOMETRY-ROTATION-FN" class="footnote"><sup class="footnote" id="FUNCTIONS-GEOMETRY-ROTATION-FN">[a]</sup></a>
+ <code class="type">path</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">path '((0,0),(1,0),(1,1))' * point '(3.0,0)'</code>
+ → <code class="returnvalue">((0,0),(3,0),(3,3))</code>
+ </p>
+ <p>
+ <code class="literal">path '((0,0),(1,0),(1,1))' * point(cosd(45), sind(45))</code>
+ → <code class="returnvalue">((0,0),​(0.7071067811865475,0.7071067811865475),​(0,1.414213562373095))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">/</code> <code class="type">point</code>
+ → <code class="returnvalue"><em class="replaceable"><code>geometric_type</code></em></code>
+ </p>
+ <p>
+ Divides each point of the first argument by the second
+ <code class="type">point</code> (treating a point as being a complex number
+ represented by real and imaginary parts, and performing standard
+ complex division). If one interprets
+ the second <code class="type">point</code> as a vector, this is equivalent to
+ scaling the object's size and distance from the origin down by the
+ length of the vector, and rotating it clockwise around the origin by
+ the vector's angle from the <em class="replaceable"><code>x</code></em> axis.
+ Available for <code class="type">point</code>, <code class="type">box</code>,<a href="functions-geometry.html#ftn.FUNCTIONS-GEOMETRY-ROTATION-FN" class="footnoteref"><sup class="footnoteref">[a]</sup></a> <code class="type">path</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">path '((0,0),(1,0),(1,1))' / point '(2.0,0)'</code>
+ → <code class="returnvalue">((0,0),(0.5,0),(0.5,0.5))</code>
+ </p>
+ <p>
+ <code class="literal">path '((0,0),(1,0),(1,1))' / point(cosd(45), sind(45))</code>
+ → <code class="returnvalue">((0,0),​(0.7071067811865476,-0.7071067811865476),​(1.4142135623730951,0))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="literal">@-@</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes the total length.
+ Available for <code class="type">lseg</code>, <code class="type">path</code>.
+ </p>
+ <p>
+ <code class="literal">@-@ path '[(0,0),(1,0),(1,1)]'</code>
+ → <code class="returnvalue">2</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="literal">@@</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes the center point.
+ Available for <code class="type">box</code>, <code class="type">lseg</code>,
+ <code class="type">polygon</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">@@ box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">(1,1)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="literal">#</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">integer</code>
+ </p>
+ <p>
+ Returns the number of points.
+ Available for <code class="type">path</code>, <code class="type">polygon</code>.
+ </p>
+ <p>
+ <code class="literal"># path '((1,0),(0,1),(-1,0))'</code>
+ → <code class="returnvalue">3</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">#</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes the point of intersection, or NULL if there is none.
+ Available for <code class="type">lseg</code>, <code class="type">line</code>.
+ </p>
+ <p>
+ <code class="literal">lseg '[(0,0),(1,1)]' # lseg '[(1,0),(0,1)]'</code>
+ → <code class="returnvalue">(0.5,0.5)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">box</code> <code class="literal">#</code> <code class="type">box</code>
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Computes the intersection of two boxes, or NULL if there is none.
+ </p>
+ <p>
+ <code class="literal">box '(2,2),(-1,-1)' # box '(1,1),(-2,-2)'</code>
+ → <code class="returnvalue">(1,1),(-1,-1)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">##</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes the closest point to the first object on the second object.
+ Available for these pairs of types:
+ (<code class="type">point</code>, <code class="type">box</code>),
+ (<code class="type">point</code>, <code class="type">lseg</code>),
+ (<code class="type">point</code>, <code class="type">line</code>),
+ (<code class="type">lseg</code>, <code class="type">box</code>),
+ (<code class="type">lseg</code>, <code class="type">lseg</code>),
+ (<code class="type">line</code>, <code class="type">lseg</code>).
+ </p>
+ <p>
+ <code class="literal">point '(0,0)' ## lseg '[(2,0),(0,2)]'</code>
+ → <code class="returnvalue">(1,1)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&lt;-&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes the distance between the objects.
+ Available for all seven geometric types, for all combinations
+ of <code class="type">point</code> with another geometric type, and for
+ these additional pairs of types:
+ (<code class="type">box</code>, <code class="type">lseg</code>),
+ (<code class="type">lseg</code>, <code class="type">line</code>),
+ (<code class="type">polygon</code>, <code class="type">circle</code>)
+ (and the commutator cases).
+ </p>
+ <p>
+ <code class="literal">circle '&lt;(0,0),1&gt;' &lt;-&gt; circle '&lt;(5,0),1&gt;'</code>
+ → <code class="returnvalue">3</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">@&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Does first object contain second?
+ Available for these pairs of types:
+ (<code class="literal">box</code>, <code class="literal">point</code>),
+ (<code class="literal">box</code>, <code class="literal">box</code>),
+ (<code class="literal">path</code>, <code class="literal">point</code>),
+ (<code class="literal">polygon</code>, <code class="literal">point</code>),
+ (<code class="literal">polygon</code>, <code class="literal">polygon</code>),
+ (<code class="literal">circle</code>, <code class="literal">point</code>),
+ (<code class="literal">circle</code>, <code class="literal">circle</code>).
+ </p>
+ <p>
+ <code class="literal">circle '&lt;(0,0),2&gt;' @&gt; point '(1,1)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&lt;@</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object contained in or on second?
+ Available for these pairs of types:
+ (<code class="literal">point</code>, <code class="literal">box</code>),
+ (<code class="literal">point</code>, <code class="literal">lseg</code>),
+ (<code class="literal">point</code>, <code class="literal">line</code>),
+ (<code class="literal">point</code>, <code class="literal">path</code>),
+ (<code class="literal">point</code>, <code class="literal">polygon</code>),
+ (<code class="literal">point</code>, <code class="literal">circle</code>),
+ (<code class="literal">box</code>, <code class="literal">box</code>),
+ (<code class="literal">lseg</code>, <code class="literal">box</code>),
+ (<code class="literal">lseg</code>, <code class="literal">line</code>),
+ (<code class="literal">polygon</code>, <code class="literal">polygon</code>),
+ (<code class="literal">circle</code>, <code class="literal">circle</code>).
+ </p>
+ <p>
+ <code class="literal">point '(1,1)' &lt;@ circle '&lt;(0,0),2&gt;'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&amp;&amp;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Do these objects overlap? (One point in common makes this true.)
+ Available for <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(1,1),(0,0)' &amp;&amp; box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&lt;&lt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object strictly left of second?
+ Available for <code class="type">point</code>, <code class="type">box</code>,
+ <code class="type">polygon</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">circle '&lt;(0,0),1&gt;' &lt;&lt; circle '&lt;(5,0),1&gt;'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&gt;&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object strictly right of second?
+ Available for <code class="type">point</code>, <code class="type">box</code>,
+ <code class="type">polygon</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">circle '&lt;(5,0),1&gt;' &gt;&gt; circle '&lt;(0,0),1&gt;'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&amp;&lt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Does first object not extend to the right of second?
+ Available for <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(1,1),(0,0)' &amp;&lt; box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&amp;&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Does first object not extend to the left of second?
+ Available for <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(3,3),(0,0)' &amp;&gt; box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&lt;&lt;|</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object strictly below second?
+ Available for <code class="type">point</code>, <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(3,3),(0,0)' &lt;&lt;| box '(5,5),(3,4)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">|&gt;&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object strictly above second?
+ Available for <code class="type">point</code>, <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(5,5),(3,4)' |&gt;&gt; box '(3,3),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">&amp;&lt;|</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Does first object not extend above second?
+ Available for <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(1,1),(0,0)' &amp;&lt;| box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">|&amp;&gt;</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Does first object not extend below second?
+ Available for <code class="type">box</code>, <code class="type">polygon</code>,
+ <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">box '(3,3),(0,0)' |&amp;&gt; box '(2,2),(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">box</code> <code class="literal">&lt;^</code> <code class="type">box</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object below second (allows edges to touch)?
+ </p>
+ <p>
+ <code class="literal">box '((1,1),(0,0))' &lt;^ box '((2,2),(1,1))'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">box</code> <code class="literal">&gt;^</code> <code class="type">box</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is first object above second (allows edges to touch)?
+ </p>
+ <p>
+ <code class="literal">box '((2,2),(1,1))' &gt;^ box '((1,1),(0,0))'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">?#</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Do these objects intersect?
+ Available for these pairs of types:
+ (<code class="type">box</code>, <code class="type">box</code>),
+ (<code class="type">lseg</code>, <code class="type">box</code>),
+ (<code class="type">lseg</code>, <code class="type">lseg</code>),
+ (<code class="type">lseg</code>, <code class="type">line</code>),
+ (<code class="type">line</code>, <code class="type">box</code>),
+ (<code class="type">line</code>, <code class="type">line</code>),
+ (<code class="type">path</code>, <code class="type">path</code>).
+ </p>
+ <p>
+ <code class="literal">lseg '[(-1,0),(1,0)]' ?# box '(2,2),(-2,-2)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="literal">?-</code> <code class="type">line</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p class="func_signature">
+ <code class="literal">?-</code> <code class="type">lseg</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is line horizontal?
+ </p>
+ <p>
+ <code class="literal">?- lseg '[(-1,0),(1,0)]'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">point</code> <code class="literal">?-</code> <code class="type">point</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Are points horizontally aligned (that is, have same y coordinate)?
+ </p>
+ <p>
+ <code class="literal">point '(1,0)' ?- point '(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="literal">?|</code> <code class="type">line</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p class="func_signature">
+ <code class="literal">?|</code> <code class="type">lseg</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is line vertical?
+ </p>
+ <p>
+ <code class="literal">?| lseg '[(-1,0),(1,0)]'</code>
+ → <code class="returnvalue">f</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">point</code> <code class="literal">?|</code> <code class="type">point</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Are points vertically aligned (that is, have same x coordinate)?
+ </p>
+ <p>
+ <code class="literal">point '(0,1)' ?| point '(0,0)'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">line</code> <code class="literal">?-|</code> <code class="type">line</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p class="func_signature">
+ <code class="type">lseg</code> <code class="literal">?-|</code> <code class="type">lseg</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Are lines perpendicular?
+ </p>
+ <p>
+ <code class="literal">lseg '[(0,0),(0,1)]' ?-| lseg '[(0,0),(1,0)]'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="type">line</code> <code class="literal">?||</code> <code class="type">line</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p class="func_signature">
+ <code class="type">lseg</code> <code class="literal">?||</code> <code class="type">lseg</code>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Are lines parallel?
+ </p>
+ <p>
+ <code class="literal">lseg '[(-1,0),(1,0)]' ?|| lseg '[(-1,2),(1,2)]'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <em class="replaceable"><code>geometric_type</code></em> <code class="literal">~=</code> <em class="replaceable"><code>geometric_type</code></em>
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Are these objects the same?
+ Available for <code class="type">point</code>, <code class="type">box</code>,
+ <code class="type">polygon</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">polygon '((0,0),(1,1))' ~= polygon '((1,1),(0,0))'</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr></tbody><tbody class="footnotes"><tr><td colspan="1"><div id="ftn.FUNCTIONS-GEOMETRY-ROTATION-FN" class="footnote"><p><a href="#FUNCTIONS-GEOMETRY-ROTATION-FN" class="para"><sup class="para">[a] </sup></a><span class="quote">“<span class="quote">Rotating</span>”</span> a
+ box with these operators only moves its corner points: the box is
+ still considered to have sides parallel to the axes. Hence the box's
+ size is not preserved, as a true rotation would do.</p></div></td></tr></tbody></table></div></div><br class="table-break" /><div class="caution"><h3 class="title">Caution</h3><p>
+ Note that the <span class="quote">“<span class="quote">same as</span>”</span> operator, <code class="literal">~=</code>,
+ represents the usual notion of equality for the <code class="type">point</code>,
+ <code class="type">box</code>, <code class="type">polygon</code>, and <code class="type">circle</code> types.
+ Some of the geometric types also have an <code class="literal">=</code> operator, but
+ <code class="literal">=</code> compares for equal <span class="emphasis"><em>areas</em></span> only.
+ The other scalar comparison operators (<code class="literal">&lt;=</code> and so
+ on), where available for these types, likewise compare areas.
+ </p></div><div class="note"><h3 class="title">Note</h3><p>
+ Before <span class="productname">PostgreSQL</span> 14, the point
+ is strictly below/above comparison operators <code class="type">point</code>
+ <code class="literal">&lt;&lt;|</code> <code class="type">point</code> and <code class="type">point</code>
+ <code class="literal">|&gt;&gt;</code> <code class="type">point</code> were respectively
+ called <code class="literal">&lt;^</code> and <code class="literal">&gt;^</code>. These
+ names are still available, but are deprecated and will eventually be
+ removed.
+ </p></div><div class="table" id="FUNCTIONS-GEOMETRY-FUNC-TABLE"><p class="title"><strong>Table 9.37. Geometric Functions</strong></p><div class="table-contents"><table class="table" summary="Geometric Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature">
+ Function
+ </p>
+ <p>
+ Description
+ </p>
+ <p>
+ Example(s)
+ </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.1.1.1.1" class="indexterm"></a>
+ <code class="function">area</code> ( <em class="replaceable"><code>geometric_type</code></em> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes area.
+ Available for <code class="type">box</code>, <code class="type">path</code>, <code class="type">circle</code>.
+ A <code class="type">path</code> input must be closed, else NULL is returned.
+ Also, if the <code class="type">path</code> is self-intersecting, the result may be
+ meaningless.
+ </p>
+ <p>
+ <code class="literal">area(box '(2,2),(0,0)')</code>
+ → <code class="returnvalue">4</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.2.1.1.1" class="indexterm"></a>
+ <code class="function">center</code> ( <em class="replaceable"><code>geometric_type</code></em> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes center point.
+ Available for <code class="type">box</code>, <code class="type">circle</code>.
+ </p>
+ <p>
+ <code class="literal">center(box '(1,2),(0,0)')</code>
+ → <code class="returnvalue">(0.5,1)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.3.1.1.1" class="indexterm"></a>
+ <code class="function">diagonal</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">lseg</code>
+ </p>
+ <p>
+ Extracts box's diagonal as a line segment
+ (same as <code class="function">lseg(box)</code>).
+ </p>
+ <p>
+ <code class="literal">diagonal(box '(1,2),(0,0)')</code>
+ → <code class="returnvalue">[(1,2),(0,0)]</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.4.1.1.1" class="indexterm"></a>
+ <code class="function">diameter</code> ( <code class="type">circle</code> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes diameter of circle.
+ </p>
+ <p>
+ <code class="literal">diameter(circle '&lt;(0,0),2&gt;')</code>
+ → <code class="returnvalue">4</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.5.1.1.1" class="indexterm"></a>
+ <code class="function">height</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes vertical size of box.
+ </p>
+ <p>
+ <code class="literal">height(box '(1,2),(0,0)')</code>
+ → <code class="returnvalue">2</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.6.1.1.1" class="indexterm"></a>
+ <code class="function">isclosed</code> ( <code class="type">path</code> )
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is path closed?
+ </p>
+ <p>
+ <code class="literal">isclosed(path '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.7.1.1.1" class="indexterm"></a>
+ <code class="function">isopen</code> ( <code class="type">path</code> )
+ → <code class="returnvalue">boolean</code>
+ </p>
+ <p>
+ Is path open?
+ </p>
+ <p>
+ <code class="literal">isopen(path '[(0,0),(1,1),(2,0)]')</code>
+ → <code class="returnvalue">t</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.8.1.1.1" class="indexterm"></a>
+ <code class="function">length</code> ( <em class="replaceable"><code>geometric_type</code></em> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes the total length.
+ Available for <code class="type">lseg</code>, <code class="type">path</code>.
+ </p>
+ <p>
+ <code class="literal">length(path '((-1,0),(1,0))')</code>
+ → <code class="returnvalue">4</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.9.1.1.1" class="indexterm"></a>
+ <code class="function">npoints</code> ( <em class="replaceable"><code>geometric_type</code></em> )
+ → <code class="returnvalue">integer</code>
+ </p>
+ <p>
+ Returns the number of points.
+ Available for <code class="type">path</code>, <code class="type">polygon</code>.
+ </p>
+ <p>
+ <code class="literal">npoints(path '[(0,0),(1,1),(2,0)]')</code>
+ → <code class="returnvalue">3</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.10.1.1.1" class="indexterm"></a>
+ <code class="function">pclose</code> ( <code class="type">path</code> )
+ → <code class="returnvalue">path</code>
+ </p>
+ <p>
+ Converts path to closed form.
+ </p>
+ <p>
+ <code class="literal">pclose(path '[(0,0),(1,1),(2,0)]')</code>
+ → <code class="returnvalue">((0,0),(1,1),(2,0))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.11.1.1.1" class="indexterm"></a>
+ <code class="function">popen</code> ( <code class="type">path</code> )
+ → <code class="returnvalue">path</code>
+ </p>
+ <p>
+ Converts path to open form.
+ </p>
+ <p>
+ <code class="literal">popen(path '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">[(0,0),(1,1),(2,0)]</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.12.1.1.1" class="indexterm"></a>
+ <code class="function">radius</code> ( <code class="type">circle</code> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes radius of circle.
+ </p>
+ <p>
+ <code class="literal">radius(circle '&lt;(0,0),2&gt;')</code>
+ → <code class="returnvalue">2</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.13.1.1.1" class="indexterm"></a>
+ <code class="function">slope</code> ( <code class="type">point</code>, <code class="type">point</code> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes slope of a line drawn through the two points.
+ </p>
+ <p>
+ <code class="literal">slope(point '(0,0)', point '(2,1)')</code>
+ → <code class="returnvalue">0.5</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.6.2.2.14.1.1.1" class="indexterm"></a>
+ <code class="function">width</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">double precision</code>
+ </p>
+ <p>
+ Computes horizontal size of box.
+ </p>
+ <p>
+ <code class="literal">width(box '(1,2),(0,0)')</code>
+ → <code class="returnvalue">1</code>
+ </p></td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-GEOMETRY-CONV-TABLE"><p class="title"><strong>Table 9.38. Geometric Type Conversion Functions</strong></p><div class="table-contents"><table class="table" summary="Geometric Type Conversion Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature">
+ Function
+ </p>
+ <p>
+ Description
+ </p>
+ <p>
+ Example(s)
+ </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.1.1.1.1" class="indexterm"></a>
+ <code class="function">box</code> ( <code class="type">circle</code> )
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Computes box inscribed within the circle.
+ </p>
+ <p>
+ <code class="literal">box(circle '&lt;(0,0),2&gt;')</code>
+ → <code class="returnvalue">(1.414213562373095,1.414213562373095),​(-1.414213562373095,-1.414213562373095)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">box</code> ( <code class="type">point</code> )
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Converts point to empty box.
+ </p>
+ <p>
+ <code class="literal">box(point '(1,0)')</code>
+ → <code class="returnvalue">(1,0),(1,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">box</code> ( <code class="type">point</code>, <code class="type">point</code> )
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Converts any two corner points to box.
+ </p>
+ <p>
+ <code class="literal">box(point '(0,1)', point '(1,0)')</code>
+ → <code class="returnvalue">(1,1),(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">box</code> ( <code class="type">polygon</code> )
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Computes bounding box of polygon.
+ </p>
+ <p>
+ <code class="literal">box(polygon '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">(2,1),(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.5.1.1.1" class="indexterm"></a>
+ <code class="function">bound_box</code> ( <code class="type">box</code>, <code class="type">box</code> )
+ → <code class="returnvalue">box</code>
+ </p>
+ <p>
+ Computes bounding box of two boxes.
+ </p>
+ <p>
+ <code class="literal">bound_box(box '(1,1),(0,0)', box '(4,4),(3,3)')</code>
+ → <code class="returnvalue">(4,4),(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.6.1.1.1" class="indexterm"></a>
+ <code class="function">circle</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">circle</code>
+ </p>
+ <p>
+ Computes smallest circle enclosing box.
+ </p>
+ <p>
+ <code class="literal">circle(box '(1,1),(0,0)')</code>
+ → <code class="returnvalue">&lt;(0.5,0.5),0.7071067811865476&gt;</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">circle</code> ( <code class="type">point</code>, <code class="type">double precision</code> )
+ → <code class="returnvalue">circle</code>
+ </p>
+ <p>
+ Constructs circle from center and radius.
+ </p>
+ <p>
+ <code class="literal">circle(point '(0,0)', 2.0)</code>
+ → <code class="returnvalue">&lt;(0,0),2&gt;</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">circle</code> ( <code class="type">polygon</code> )
+ → <code class="returnvalue">circle</code>
+ </p>
+ <p>
+ Converts polygon to circle. The circle's center is the mean of the
+ positions of the polygon's points, and the radius is the average
+ distance of the polygon's points from that center.
+ </p>
+ <p>
+ <code class="literal">circle(polygon '((0,0),(1,3),(2,0))')</code>
+ → <code class="returnvalue">&lt;(1,1),1.6094757082487299&gt;</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.9.1.1.1" class="indexterm"></a>
+ <code class="function">line</code> ( <code class="type">point</code>, <code class="type">point</code> )
+ → <code class="returnvalue">line</code>
+ </p>
+ <p>
+ Converts two points to the line through them.
+ </p>
+ <p>
+ <code class="literal">line(point '(-1,0)', point '(1,0)')</code>
+ → <code class="returnvalue">{0,-1,0}</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.10.1.1.1" class="indexterm"></a>
+ <code class="function">lseg</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">lseg</code>
+ </p>
+ <p>
+ Extracts box's diagonal as a line segment.
+ </p>
+ <p>
+ <code class="literal">lseg(box '(1,0),(-1,0)')</code>
+ → <code class="returnvalue">[(1,0),(-1,0)]</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">lseg</code> ( <code class="type">point</code>, <code class="type">point</code> )
+ → <code class="returnvalue">lseg</code>
+ </p>
+ <p>
+ Constructs line segment from two endpoints.
+ </p>
+ <p>
+ <code class="literal">lseg(point '(-1,0)', point '(1,0)')</code>
+ → <code class="returnvalue">[(-1,0),(1,0)]</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.12.1.1.1" class="indexterm"></a>
+ <code class="function">path</code> ( <code class="type">polygon</code> )
+ → <code class="returnvalue">path</code>
+ </p>
+ <p>
+ Converts polygon to a closed path with the same list of points.
+ </p>
+ <p>
+ <code class="literal">path(polygon '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">((0,0),(1,1),(2,0))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.13.1.1.1" class="indexterm"></a>
+ <code class="function">point</code> ( <code class="type">double precision</code>, <code class="type">double precision</code> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Constructs point from its coordinates.
+ </p>
+ <p>
+ <code class="literal">point(23.4, -44.5)</code>
+ → <code class="returnvalue">(23.4,-44.5)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">point</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes center of box.
+ </p>
+ <p>
+ <code class="literal">point(box '(1,0),(-1,0)')</code>
+ → <code class="returnvalue">(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">point</code> ( <code class="type">circle</code> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes center of circle.
+ </p>
+ <p>
+ <code class="literal">point(circle '&lt;(0,0),2&gt;')</code>
+ → <code class="returnvalue">(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">point</code> ( <code class="type">lseg</code> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes center of line segment.
+ </p>
+ <p>
+ <code class="literal">point(lseg '[(-1,0),(1,0)]')</code>
+ → <code class="returnvalue">(0,0)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">point</code> ( <code class="type">polygon</code> )
+ → <code class="returnvalue">point</code>
+ </p>
+ <p>
+ Computes center of polygon (the mean of the
+ positions of the polygon's points).
+ </p>
+ <p>
+ <code class="literal">point(polygon '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">(1,0.3333333333333333)</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <a id="id-1.5.8.17.7.2.2.18.1.1.1" class="indexterm"></a>
+ <code class="function">polygon</code> ( <code class="type">box</code> )
+ → <code class="returnvalue">polygon</code>
+ </p>
+ <p>
+ Converts box to a 4-point polygon.
+ </p>
+ <p>
+ <code class="literal">polygon(box '(1,1),(0,0)')</code>
+ → <code class="returnvalue">((0,0),(0,1),(1,1),(1,0))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">polygon</code> ( <code class="type">circle</code> )
+ → <code class="returnvalue">polygon</code>
+ </p>
+ <p>
+ Converts circle to a 12-point polygon.
+ </p>
+ <p>
+ <code class="literal">polygon(circle '&lt;(0,0),2&gt;')</code>
+ → <code class="returnvalue">((-2,0),​(-1.7320508075688774,0.9999999999999999),​(-1.0000000000000002,1.7320508075688772),​(-1.2246063538223773e-16,2),​(0.9999999999999996,1.7320508075688774),​(1.732050807568877,1.0000000000000007),​(2,2.4492127076447545e-16),​(1.7320508075688776,-0.9999999999999994),​(1.0000000000000009,-1.7320508075688767),​(3.673819061467132e-16,-2),​(-0.9999999999999987,-1.732050807568878),​(-1.7320508075688767,-1.0000000000000009))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">polygon</code> ( <code class="type">integer</code>, <code class="type">circle</code> )
+ → <code class="returnvalue">polygon</code>
+ </p>
+ <p>
+ Converts circle to an <em class="replaceable"><code>n</code></em>-point polygon.
+ </p>
+ <p>
+ <code class="literal">polygon(4, circle '&lt;(3,0),1&gt;')</code>
+ → <code class="returnvalue">((2,0),​(3,1),​(4,1.2246063538223773e-16),​(3,-1))</code>
+ </p></td></tr><tr><td class="func_table_entry"><p class="func_signature">
+ <code class="function">polygon</code> ( <code class="type">path</code> )
+ → <code class="returnvalue">polygon</code>
+ </p>
+ <p>
+ Converts closed path to a polygon with the same list of points.
+ </p>
+ <p>
+ <code class="literal">polygon(path '((0,0),(1,1),(2,0))')</code>
+ → <code class="returnvalue">((0,0),(1,1),(2,0))</code>
+ </p></td></tr></tbody></table></div></div><br class="table-break" /><p>
+ It is possible to access the two component numbers of a <code class="type">point</code>
+ as though the point were an array with indexes 0 and 1. For example, if
+ <code class="literal">t.p</code> is a <code class="type">point</code> column then
+ <code class="literal">SELECT p[0] FROM t</code> retrieves the X coordinate and
+ <code class="literal">UPDATE t SET p[1] = ...</code> changes the Y coordinate.
+ In the same way, a value of type <code class="type">box</code> or <code class="type">lseg</code> can be treated
+ as an array of two <code class="type">point</code> values.
+ </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="functions-enum.html" title="9.10. Enum Support Functions">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="functions-net.html" title="9.12. Network Address Functions and Operators">Next</a></td></tr><tr><td width="40%" align="left" valign="top">9.10. Enum Support Functions </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 9.12. Network Address Functions and Operators</td></tr></table></div></body></html> \ No newline at end of file