<title>

Polygon

</title>

<para>

The aggregate function

The functions <literal>spoly</literal> and <literal>spoly_deg</literal>

can be used to create spherical polygons. Function <literal>spoly</literal>

is overloaded and can accept arrays of float8 or spoint elements.

There are the same restrictions as for using the input function of

spherical polygon (see <xref linkend="dt.spoly"/>).

</para>

<funcsynopsis>

<funcprototype>

<funcdef><function>spoly</function></funcdef>

<paramdef>spoint <parameter>edge</parameter></paramdef>

</funcprototype>

</funcsynopsis>

<para>

can be used to create apolygon froma set ofspherical points.

<literal>NULL</literal>, if the polygon couldn't be created.

Create a sphericalpolygon froman array ofpair-consecutive

</programlisting>

</para>

<para>

Create a spherical polygon from an array of spoint elements.

<programlisting>

<![CDATA[sql> SELECT spoly(ARRAY[spoint(0, 0), spoint(0, 0.5), spoint(0.5, 0.5), spoint(0.5, 0)])]]>

</programlisting>

</para>

<para>

Create a spherical polygon from an array of pair-consecutive

numbers (lng, lat). The coordinates are specified in degrees.

<programlisting>

<![CDATA[sql> SELECT spoly_deg(ARRAY[0, 0, 0, 10, 10, 10, 10, 0])]]>

</programlisting>

</para>

<para>

The aggregate function <literal>spoly</literal> can be used to

create a polygon from a set of spherical points. The function

returns <literal>NULL</literal>, if the polygon could not be

created.

</para>

<example>

<title>

Create a spherical polygon using a set of spherical points