Commit bba7d111 authored by Sandro Santilli's avatar Sandro Santilli

Improve documentation for GetRingEdges (#3046)

git-svn-id: http://svn.osgeo.org/postgis/[email protected] b70326c6-7e19-0410-871a-916f4a2858ee
parent aab816f8
......@@ -2145,7 +2145,8 @@ SELECT ST_AsText(topology.ST_GetFaceGeometry('ma_topo', 1)) As facegeomwkt;
<refname>GetRingEdges</refname>
<refpurpose>
Returns an ordered set of edges forming a ring with the given edge .
Returns the ordered set of signed edge identifiers met by walking on an
a given edge side.
</refpurpose>
</refnamediv>
......@@ -2164,12 +2165,18 @@ Returns an ordered set of edges forming a ring with the given edge .
<title>Description</title>
<para>
Returns an ordered set of edges forming a ring with the given edge.
Returns the ordered set of signed edge identifiers met by walking on an
a given edge side.
Each output consists of a sequence and a signed edge id.
Sequence numbers start with value 1.
A negative edge identifier means that the given edge is taken backward.
You can pass a negative edge id to start walking backward.
</para>
</para>
<para>
If you pass a positive edge id, the walk starts on the left side
of the corresponding edge and follows the edge direction.
If you pass a negative edge id, the walk starts on the right side
of it and goes backward.
</para>
<para>
If <varname>max_edges</varname> is not null no more than those records
......@@ -2177,9 +2184,12 @@ are returned by that function. This is meant to be a safety parameter
when dealing with possibly invalid topologies.
</para>
<note><para>
This function uses edge ring linking metadata.
</para></note>
<!-- use this format if new function -->
<para>Availability: 2.0 </para>
<para>Availability: 2.0.0 </para>
</refsection>
......
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