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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="DATATYPE-GEOMETRIC"
>8.8. Geometric Types</A
></H1
><P
> Geometric data types represent two-dimensional spatial
objects. <A
HREF="datatype-geometric.html#DATATYPE-GEO-TABLE"
>Table 8-19</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
><B
>Table 8-19. Geometric Types</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><THEAD
><TR
><TH
>Name</TH
><TH
>Storage Size</TH
><TH
>Representation</TH
><TH
>Description</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="TYPE"
>point</TT
></TD
><TD
>16 bytes</TD
><TD
>Point on a plane</TD
><TD
>(x,y)</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>line</TT
></TD
><TD
>32 bytes</TD
><TD
>Infinite line (not fully implemented)</TD
><TD
>((x1,y1),(x2,y2))</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>lseg</TT
></TD
><TD
>32 bytes</TD
><TD
>Finite line segment</TD
><TD
>((x1,y1),(x2,y2))</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>box</TT
></TD
><TD
>32 bytes</TD
><TD
>Rectangular box</TD
><TD
>((x1,y1),(x2,y2))</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>path</TT
></TD
><TD
>16+16n bytes</TD
><TD
>Closed path (similar to polygon)</TD
><TD
>((x1,y1),...)</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>path</TT
></TD
><TD
>16+16n bytes</TD
><TD
>Open path</TD
><TD
>[(x1,y1),...]</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>polygon</TT
></TD
><TD
>40+16n bytes</TD
><TD
>Polygon (similar to closed path)</TD
><TD
>((x1,y1),...)</TD
></TR
><TR
><TD
><TT
CLASS="TYPE"
>circle</TT
></TD
><TD
>24 bytes</TD
><TD
>Circle</TD
><TD
><(x,y),r> (center point and radius)</TD
></TR
></TBODY
></TABLE
></DIV
><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"
>Section 9.11</A
>.
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN6191"
>8.8.1. Points</A
></H2
><P
> Points are the fundamental two-dimensional building block for geometric types.
Values of type <TT
CLASS="TYPE"
>point</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>( <TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> )
<TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
></PRE
><P>
where <TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> and <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> are the respective
coordinates, as floating-point numbers.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN6204"
>8.8.2. Line Segments</A
></H2
><P
> Line segments (<TT
CLASS="TYPE"
>lseg</TT
>) are represented by pairs of points.
Values of type <TT
CLASS="TYPE"
>lseg</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>( ( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ( <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
> ) )
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ( <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
> )
<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
></PRE
><P>
where
<TT
CLASS="LITERAL"
>(<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
>,<TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
>)</TT
>
and
<TT
CLASS="LITERAL"
>(<TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
>,<TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
>)</TT
>
are the end points of the line segment.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN6232"
>8.8.3. Boxes</A
></H2
><P
> Boxes are represented by pairs of points that are opposite
corners of the box.
Values of type <TT
CLASS="TYPE"
>box</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>( ( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ( <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
> ) )
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ( <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
> )
<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
></PRE
><P>
where
<TT
CLASS="LITERAL"
>(<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
>,<TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
>)</TT
>
and
<TT
CLASS="LITERAL"
>(<TT
CLASS="REPLACEABLE"
><I
>x2</I
></TT
>,<TT
CLASS="REPLACEABLE"
><I
>y2</I
></TT
>)</TT
>
are any two opposite corners of the box.
</P
><P
> Boxes are output using the first syntax.
Any two opposite corners can be supplied on input, but the values
will be reordered as needed to store the
upper right and lower left corners.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN6260"
>8.8.4. Paths</A
></H2
><P
> Paths are represented by lists of connected points. Paths can be
<I
CLASS="FIRSTTERM"
>open</I
>, where
the first and last points in the list are considered not connected, or
<I
CLASS="FIRSTTERM"
>closed</I
>,
where the first and last points are considered connected.
</P
><P
> Values of type <TT
CLASS="TYPE"
>path</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>( ( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ... , ( <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> ) )
[ ( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ... , ( <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> ) ]
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ... , ( <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> )
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , ... , <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> )
<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , ... , <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> </PRE
><P>
where the points are the end points of the line segments
comprising the path. Square brackets (<TT
CLASS="LITERAL"
>[]</TT
>) indicate
an open path, while parentheses (<TT
CLASS="LITERAL"
>()</TT
>) indicate a
closed path.
</P
><P
> Paths are output using the first or second syntax, as appropriate.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN6293"
>8.8.5. Polygons</A
></H2
><P
> Polygons are represented by lists of points (the vertexes of the
polygon). Polygons are very similar to closed paths, but are
stored differently
and have their own set of support routines.
</P
><P
> Values of type <TT
CLASS="TYPE"
>polygon</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>( ( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ... , ( <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> ) )
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> ) , ... , ( <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> )
( <TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , ... , <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> )
<TT
CLASS="REPLACEABLE"
><I
>x1</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y1</I
></TT
> , ... , <TT
CLASS="REPLACEABLE"
><I
>xn</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>yn</I
></TT
> </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"
><H2
CLASS="SECT2"
><A
NAME="AEN6318"
>8.8.6. Circles</A
></H2
><P
> Circles are represented by a center point and radius.
Values of type <TT
CLASS="TYPE"
>circle</TT
> are specified using the following syntax:
</P><PRE
CLASS="SYNOPSIS"
>< ( <TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> ) , <TT
CLASS="REPLACEABLE"
><I
>r</I
></TT
> >
( ( <TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> ) , <TT
CLASS="REPLACEABLE"
><I
>r</I
></TT
> )
( <TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> ) , <TT
CLASS="REPLACEABLE"
><I
>r</I
></TT
>
<TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
> , <TT
CLASS="REPLACEABLE"
><I
>r</I
></TT
> </PRE
><P>
where
<TT
CLASS="LITERAL"
>(<TT
CLASS="REPLACEABLE"
><I
>x</I
></TT
>,<TT
CLASS="REPLACEABLE"
><I
>y</I
></TT
>)</TT
>
is the center point and <TT
CLASS="REPLACEABLE"
><I
>r</I
></TT
> is the radius of the circle.
</P
><P
> Circles are output using the first syntax.
</P
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