#2603: provide a lame example with hopes to come up with a better one in future.

git-svn-id: http://svn.osgeo.org/postgis/trunk@14199 b70326c6-7e19-0410-871a-916f4a2858ee

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diff --git a/doc/html/images/st_mapalgebramask02.png b/doc/html/images/st_mapalgebramask02.png
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diff --git a/doc/html/images/st_mapalgebramask03.png b/doc/html/images/st_mapalgebramask03.png
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diff --git a/doc/html/images/st_mapalgebramask04.png b/doc/html/images/st_mapalgebramask04.png
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diff --git a/doc/reference_raster.xml b/doc/reference_raster.xml
index 5c248f638c3229c3f52cc8dd429375d9e343f7fb..0969ed0686fc9121cc4b54ed066db39deac4c402 100644 (file)
--- a/doc/reference_raster.xml
+++ b/doc/reference_raster.xml
@@ -9535,24 +9535,96 @@ WHERE t1.rid = 1
                                
                                <refsection>
                                        <title>Examples: Using Masks</title>
-
-                                       <para>Create our dummy table</para>
                                        <programlisting>
-WITH foo AS (
-       SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast UNION ALL
-       SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI', 300, 0) AS rast
-)
-SELECT
-       ST_MapAlgebra(
-               t1.rast, 2,
-               t2.rast, 1,
-               'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
-       ) AS rast
-FROM foo t1
-CROSS JOIN foo t2
-WHERE t1.rid = 1
-       AND t2.rid = 2
+WITH foo AS (SELECT 
+   ST_SetBandNoDataValue(
+ST_SetValue(ST_SetValue(ST_AsRaster(
+               ST_Buffer(
+                       ST_GeomFromText('LINESTRING(50 50,100 90,100 50)'), 5,'join=bevel'), 
+                       200,200,ARRAY['8BUI'], ARRAY[100], ARRAY[0]), ST_Buffer('POINT(70 70)'::geometry,10,'quad_segs=1') ,50),
+  'LINESTRING(20 20, 100 100, 150 98)'::geometry,1),0)  AS rast )
+SELECT 'original' AS title, rast
+FROM foo
+UNION ALL
+SELECT 'no mask mean value' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure) AS rast
+FROM foo
+UNION ALL
+SELECT 'mask only consider neighbors, exclude center' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure, 
+    '{{1,1,1}, {1,0,1}, {1,1,1}}'::double precision[], false) As rast
+FROM foo
+
+UNION ALL
+SELECT 'mask weighted only consider neighbors, exclude center multi otehr pixel values by 2' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])'::regprocedure, 
+    '{{2,2,2}, {2,0,2}, {2,2,2}}'::double precision[], true) As rast
+FROM foo;
                                        </programlisting>
+                                       
+                               <informaltable>
+                                               <tgroup cols="2">
+                                                       <tbody>
+                                                               <row>
+                                                                       <entry>
+                                                                               <para>
+                                                                                       <informalfigure>
+                                                                                               <mediaobject>
+                                                                                                       <imageobject>
+                                                                                                               <imagedata fileref="images/st_mapalgebramask01.png" />
+                                                                                                       </imageobject>
+                                                                                                       <caption>
+                                                                                                               <para>original</para>
+                                                                                                       </caption>
+                                                                                               </mediaobject>
+                                                                                       </informalfigure>
+                                                                               </para>
+                                                                       </entry>
+                                                                       <entry>
+                                                                               <para>
+                                                                                       <informalfigure>
+                                                                                               <mediaobject>
+                                                                                                       <imageobject>
+                                                                                                               <imagedata fileref="images/st_mapalgebramask02.png" />
+                                                                                                       </imageobject>
+                                                                                                       <caption>
+                                                                                                               <para>no mask mean value (same as having all 1s in mask matrix)</para>
+                                                                                                       </caption>
+                                                                                               </mediaobject>
+                                                                                       </informalfigure>
+                                                                               </para>
+                                                                       </entry>
+                                                               </row>
+                                                               <row>
+                                                                       <entry>
+                                                                               <para>
+                                                                                       <informalfigure>
+                                                                                               <mediaobject>
+                                                                                                       <imageobject>
+                                                                                                               <imagedata fileref="images/st_mapalgebramask03.png" />
+                                                                                                       </imageobject>
+                                                                                                       <caption>
+                                                                                                               <para>mask only consider neighbors, exclude center</para>
+                                                                                                       </caption>
+                                                                                               </mediaobject>
+                                                                                       </informalfigure>
+                                                                               </para>
+                                                                       </entry>
+                                                                       <entry>
+                                                                               <para>
+                                                                                       <informalfigure>
+                                                                                               <mediaobject>
+                                                                                                       <imageobject>
+                                                                                                               <imagedata fileref="images/st_mapalgebramask04.png" />
+                                                                                                       </imageobject>
+                                                                                                       <caption>
+                                                                                                               <para>mask weighted only consider neighbors, exclude center multi other pixel values by 2</para>
+                                                                                                       </caption>
+                                                                                               </mediaobject>
+                                                                                       </informalfigure>
+                                                                               </para>
+                                                                       </entry>
+                                                               </row>
+                                                       </tbody>
+                                               </tgroup>
+                                       </informaltable>
 
                                </refsection>