From 9cd7a3972d1fb665e1194d52e405c73b6ec3e9b5 Mon Sep 17 00:00:00 2001
From: Pierre Racine <Pierre.Racine@sbf.ulaval.ca>
Date: Thu, 1 Dec 2011 01:10:24 +0000
Subject: [PATCH] Copied from ST_Union

git-svn-id: http://svn.osgeo.org/postgis/trunk@8271 b70326c6-7e19-0410-871a-916f4a2858ee
---
 .../plpgsql/st_multibandmapalgebra.sql        | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 raster/scripts/plpgsql/st_multibandmapalgebra.sql

diff --git a/raster/scripts/plpgsql/st_multibandmapalgebra.sql b/raster/scripts/plpgsql/st_multibandmapalgebra.sql
new file mode 100644
index 000000000..d69d20493
--- /dev/null
+++ b/raster/scripts/plpgsql/st_multibandmapalgebra.sql
@@ -0,0 +1,29 @@
+-----------------------------------------------------------------------
+-- ST_MultiBandMapAlgebra
+-- Return the same map algebra expression to all the band of a raster. 
+-----------------------------------------------------------------------
+CREATE OR REPLACE FUNCTION ST_MultiBandMapAlgebra(rast1 raster, 
+                                            	  rast2 raster, 
+                                                  expression text, 
+                                            	  extentexpr text) 
+    RETURNS raster AS 
+    $$
+    DECLARE
+		numband int;
+		newrast raster;
+		pixeltype text;
+		nodataval float;
+    BEGIN
+        numband := ST_NumBands(rast1);
+        IF numband != ST_NumBands(rast2) THEN
+            RAISE EXCEPTION 'ST_MultiBandMapAlgebra: Rasters do not have the same number of band';
+        END IF;
+        newrast := ST_MakeEmptyRaster(rast1);
+        FOR b IN 1..numband LOOP
+            pixeltype := ST_BandPixelType(rast1, b);
+            nodataval := ST_BandNodataValue(rast1, b);
+            newrast := ST_AddBand(newrast, NULL, ST_MapAlgebraExpr(rast1, b, rast2, b, expression, pixeltype, extentexpr, nodataval), 1);
+        END LOOP;
+    END;
+    $$
+    LANGUAGE 'plpgsql';
\ No newline at end of file
-- 
2.40.0