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<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>8.7.Geometric Types</title>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="datatype-geometric"></a>8.7.Geometric Types</h2></div></div></div>
<p>    Geometric data types represent two-dimensional spatial
    objects. <a href="datatype-geometric.html#datatype-geo-table" title="Table8.16.Geometric Types">Table8.16, &#8220;Geometric Types&#8221;</a> shows the geometric
    types available in <span class="productname">PostgreSQL</span>.  The
    most fundamental type, the point, forms the basis for all of the
    other types.
   </p>
<div class="table">
<a name="datatype-geo-table"></a><p class="title"><b>Table8.16.Geometric Types</b></p>
<div class="table-contents"><table summary="Geometric Types" border="1">
<colgroup>
<col>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Name</th>
<th>Storage Size</th>
<th>Representation</th>
<th>Description</th>
</tr></thead>
<tbody>
<tr>
<td><code class="type">point</code></td>
<td>16 bytes</td>
<td>Point on the plane</td>
<td>(x,y)</td>
</tr>
<tr>
<td><code class="type">line</code></td>
<td>32 bytes</td>
<td>Infinite line (not fully implemented)</td>
<td>((x1,y1),(x2,y2))</td>
</tr>
<tr>
<td><code class="type">lseg</code></td>
<td>32 bytes</td>
<td>Finite line segment</td>
<td>((x1,y1),(x2,y2))</td>
</tr>
<tr>
<td><code class="type">box</code></td>
<td>32 bytes</td>
<td>Rectangular box</td>
<td>((x1,y1),(x2,y2))</td>
</tr>
<tr>
<td><code class="type">path</code></td>
<td>16+16n bytes</td>
<td>Closed path (similar to polygon)</td>
<td>((x1,y1),...)</td>
</tr>
<tr>
<td><code class="type">path</code></td>
<td>16+16n bytes</td>
<td>Open path</td>
<td>[(x1,y1),...]</td>
</tr>
<tr>
<td><code class="type">polygon</code></td>
<td>40+16n bytes</td>
<td>Polygon (similar to closed path)</td>
<td>((x1,y1),...)</td>
</tr>
<tr>
<td><code class="type">circle</code></td>
<td>24 bytes</td>
<td>Circle</td>
<td>&lt;(x,y),r&gt; (center and radius)</td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break"><p>    A rich set of functions and operators is available to perform various geometric
    operations such as scaling, translation, rotation, and determining 
    intersections.  They are explained in <a href="functions-geometry.html" title="9.10.Geometric Functions and Operators">Section9.10, &#8220;Geometric Functions and Operators&#8221;</a>.
   </p>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id589831"></a>8.7.1.Points</h3></div></div></div>
<a name="id589835"></a><p>     Points are the fundamental two-dimensional building block for geometric types.
     Values of type <code class="type">point</code> are specified using the following syntax:

</p>
<pre class="synopsis">( <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em> )
  <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em></pre>
<p>

     where <em class="replaceable"><code>x</code></em> and <em class="replaceable"><code>y</code></em> are the respective
     coordinates as floating-point numbers.
    </p>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id589880"></a>8.7.2.Line Segments</h3></div></div></div>
<a name="id589884"></a><a name="id589890"></a><p>     Line segments (<code class="type">lseg</code>) are represented by pairs of points.
     Values of type <code class="type">lseg</code> are specified using the following syntax:

</p>
<pre class="synopsis">( ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ( <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em> ) )
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ( <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em> )  
    <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   ,   <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em></pre>
<p>

     where
     <code class="literal">(<em class="replaceable"><code>x1</code></em>,<em class="replaceable"><code>y1</code></em>)</code>
     and
     <code class="literal">(<em class="replaceable"><code>x2</code></em>,<em class="replaceable"><code>y2</code></em>)</code>
     are the end points of the line segment.
    </p>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id589988"></a>8.7.3.Boxes</h3></div></div></div>
<a name="id589992"></a><a name="id589999"></a><p>     Boxes are represented by pairs of points that are opposite
     corners of the box.
     Values of type <code class="type">box</code> are specified using the following syntax:

</p>
<pre class="synopsis">( ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ( <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em> ) )
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ( <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em> )  
    <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   ,   <em class="replaceable"><code>x2</code></em> , <em class="replaceable"><code>y2</code></em></pre>
<p>

     where
     <code class="literal">(<em class="replaceable"><code>x1</code></em>,<em class="replaceable"><code>y1</code></em>)</code>
     and
     <code class="literal">(<em class="replaceable"><code>x2</code></em>,<em class="replaceable"><code>y2</code></em>)</code>
     are any two opposite corners of the box.
    </p>
<p>     Boxes are output using the first syntax.
     The corners are reordered on input to store
     the upper right corner, then the lower left corner.
     Other corners of the box can be entered, but the lower
     left and upper right corners are determined from the input and stored.
    </p>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id590100"></a>8.7.4.Paths</h3></div></div></div>
<a name="id590104"></a><p>     Paths are represented by lists of connected points. Paths can be
     <em class="firstterm">open</em>, where
     the first and last points in the list are not considered connected, or
     <em class="firstterm">closed</em>,
     where the first and last points are considered connected.
    </p>
<p>     Values of type <code class="type">path</code> are specified using the following syntax:

</p>
<pre class="synopsis">( ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ... , ( <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> ) )
[ ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ... , ( <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> ) ]
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ... , ( <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> )  
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   , ... ,   <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> )  
    <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   , ... ,   <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em>    </pre>
<p>

     where the points are the end points of the line segments
     comprising the path.  Square brackets (<code class="literal">[]</code>) indicate
     an open path, while parentheses (<code class="literal">()</code>) indicate a
     closed path.
    </p>
<p>     Paths are output using the first syntax.
    </p>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id590235"></a>8.7.5.Polygons</h3></div></div></div>
<a name="id590239"></a><p>     Polygons are represented by lists of points (the vertexes of the
     polygon). Polygons should probably be
     considered equivalent to closed paths, but are stored differently 
     and have their own set of support routines.
    </p>
<p>     Values of type <code class="type">polygon</code> are specified using the following syntax:

</p>
<pre class="synopsis">( ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ... , ( <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> ) )
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em> ) , ... , ( <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> )  
  ( <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   , ... ,   <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em> )  
    <em class="replaceable"><code>x1</code></em> , <em class="replaceable"><code>y1</code></em>   , ... ,   <em class="replaceable"><code>xn</code></em> , <em class="replaceable"><code>yn</code></em>    </pre>
<p>

     where the points are the end points of the line segments
     comprising the boundary of the polygon.
    </p>
<p>     Polygons are output using the first syntax.
    </p>
</div>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="id590332"></a>8.7.6.Circles</h3></div></div></div>
<a name="id590336"></a><p>     Circles are represented by a center point and a radius.
     Values of type <code class="type">circle</code> are specified using the following syntax:

</p>
<pre class="synopsis">&lt; ( <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em> ) , <em class="replaceable"><code>r</code></em> &gt;
( ( <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em> ) , <em class="replaceable"><code>r</code></em> )
  ( <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em> ) , <em class="replaceable"><code>r</code></em>  
    <em class="replaceable"><code>x</code></em> , <em class="replaceable"><code>y</code></em>   , <em class="replaceable"><code>r</code></em>  </pre>
<p>

     where
     <code class="literal">(<em class="replaceable"><code>x</code></em>,<em class="replaceable"><code>y</code></em>)</code>
     is the center and <em class="replaceable"><code>r</code></em> is the radius of the circle.
    </p>
<p>     Circles are output using the first syntax.
    </p>
</div>
</div></body>
</html>