Document maxerr in ST_Rescale.

Patch by Sunveer Singh.

Closes https://github.com/postgis/postgis/pull/334
Closes #2921

git-svn-id: http://svn.osgeo.org/postgis/trunk@17014 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/doc/reference_raster.xml b/doc/reference_raster.xml
index 5e5995269cbc2ec854d8c3c67811ec08323f6ccb..4f2beea6c17001c92d4dbf910cba653d2252b3b4 100644 (file)
--- a/doc/reference_raster.xml
+++ b/doc/reference_raster.xml
@@ -6568,7 +6568,7 @@ FROM (
 
                                <para>When the new scalex or scaley is not a divisor of the raster width or height, the extent of the resulting raster is expanded to encompass the extent of the provided raster. If you want to be sure to retain exact input extent see <xref linkend="RT_ST_Resize" /></para>
 
-                               <para>A maxerror percent of 0.125 is used if no <varname>maxerr</varname> is specified.</para>
+                               <para><varname>maxerr</varname> is the threshold for transformation approximation by the resampling algorithm (in pixel units). A default of 0.125 is used if no <varname>maxerr</varname> is specified, which is the same value used in GDAL gdalwarp utility. If set to zero, no approximation takes place.</para>
 
                                <note><para>Refer to: <ulink url="http://www.gdal.org/gdalwarp.html">GDAL Warp resampling methods</ulink> for more details. </para></note>