From 3c87c843eff7478fa3fdf01e66ed2efc1f442524 Mon Sep 17 00:00:00 2001
From: Darafei Praliaskouski <me@komzpa.net>
Date: Sat, 21 Jul 2018 12:16:46 +0000
Subject: [PATCH] Document precision in EncodedPolyline.

Closes #3631



git-svn-id: http://svn.osgeo.org/postgis/trunk@16651 b70326c6-7e19-0410-871a-916f4a2858ee
---
 doc/reference_constructor.xml | 14 +++++++++++---
 doc/reference_output.xml      |  4 ++--
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/doc/reference_constructor.xml b/doc/reference_constructor.xml
index e2f2a01bf..e95ca01ea 100644
--- a/doc/reference_constructor.xml
+++ b/doc/reference_constructor.xml
@@ -1071,6 +1071,8 @@ SELECT
     <title>Description</title>
 
     <para>Creates a LineString from an Encoded Polyline string.</para>
+		<para>Optional <varname>precision</varname> specifies how many decimal places will be preserved in Encoded Polyline. Value should be the same on encoding and decoding, or coordinates will be incorrect.</para>
+
     <para>See http://developers.google.com/maps/documentation/utilities/polylinealgorithm</para>
     <para>Availability: 2.2.0</para>
     </refsection>
@@ -1079,10 +1081,16 @@ SELECT
     <title>Examples</title>
 
     <programlisting>
---Create a line string from a polyline
+-- Create a line string from a polyline
 SELECT ST_AsEWKT(ST_LineFromEncodedPolyline('_p~iF~ps|U_ulLnnqC_mqNvxq`@'));
---result--
-LINESTRING(-120.2 38.5,-120.95 40.7,-126.453 43.252)
+-- result --
+SRID=4326;LINESTRING(-120.2 38.5,-120.95 40.7,-126.453 43.252)
+
+-- Select different precision that was used for polyline encoding
+SELECT ST_AsEWKT(ST_LineFromEncodedPolyline('_p~iF~ps|U_ulLnnqC_mqNvxq`@',6));
+-- result --
+SRID=4326;LINESTRING(-12.02 3.85,-12.095 4.07,-12.6453 4.3252)
+
     </programlisting>
     </refsection>
 
diff --git a/doc/reference_output.xml b/doc/reference_output.xml
index a9c7f747e..92204b973 100644
--- a/doc/reference_output.xml
+++ b/doc/reference_output.xml
@@ -126,8 +126,8 @@
 		<refsection>
 		<title>Description</title>
 
-		<para>Returns the geometry as an Encoded Polyline.  This is a format very useful if you are using google maps</para>
-
+		<para>Returns the geometry as an Encoded Polyline. This format is used by Google Maps with precision=5 and by Open Source Routing Machine with precision=5 and 6.</para>
+		<para>Optional <varname>precision</varname> specifies how many decimal places will be preserved in Encoded Polyline. Value should be the same on encoding and decoding, or coordinates will be incorrect.</para>
 
 		<para>Availability: 2.2.0</para>
 		</refsection>
-- 
2.40.0