[postgis-commits] svn - r3791 - spike/wktraster/scripts

[postgis-commits at postgis.refractions.net]

Author: mloskot
Date: 2009-03-03 10:25:46 -0800 (Tue, 03 Mar 2009)
New Revision: 3791

Added:
   spike/wktraster/scripts/pixval.py
Log:
Added pixval.py script. This is a simple utility based on GDAL which help to compare pixel values while testing WKT Raster functionality.

Added: spike/wktraster/scripts/pixval.py
===================================================================
--- spike/wktraster/scripts/pixval.py	2009-03-03 18:01:11 UTC (rev 3790)
+++ spike/wktraster/scripts/pixval.py	2009-03-03 18:25:46 UTC (rev 3791)
@@ -0,0 +1,78 @@
+#! /usr/bin/env python
+#
+# $Id$
+#
+# This is a simple script based on GDAL and used to retrieve value of single raster pixel.
+# It is used in WKTRaster testing to compare raster samples.
+#
+# Copyright (C) 2009 Mateusz Loskot <mateusz at loskot.net>
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#
+from osgeo import gdal
+from osgeo import osr
+import osgeo.gdalconst as gdalc
+import struct
+import sys
+
+def pt2fmt(pt):
+    fmttypes = {
+        gdalc.GDT_Byte: 'B',
+        gdalc.GDT_Int16: 'h',
+        gdalc.GDT_UInt16: 'H',
+        gdalc.GDT_Int32: 'i',
+        gdalc.GDT_UInt32: 'I',
+        gdalc.GDT_Float32: 'f',
+        gdalc.GDT_Float64: 'f'
+        }
+    return fmttypes.get(pt, 'x')
+
+if len(sys.argv) != 5:
+    print "Usage: pixval.py <raster> <band> <x> <y>"
+    print "\traster - GDAL supported dataset"
+    print "\tband - 1-based number of band"
+    print "\tx - Pixel column - 1..N where N is raster X dimension"
+    print "\ty - Pixel row - 1..N where N is raster Y dimension"
+    sys.exit(1)
+
+infile = sys.argv[1]
+nband = int(sys.argv[2])
+x = int(sys.argv[3])
+y = int(sys.argv[4])
+
+print "File : %s" % infile
+print "Band : %d" % nband
+print "Pixel: %d x %d" % (x, y)
+
+ds = gdal.Open(infile, gdalc.GA_ReadOnly);
+if ds is None:
+    sys.exit('Cannot open input file: ' + str(infile))
+
+if x <= 0 or x > ds.RasterXSize or y <= 0 or y > ds.RasterYSize:
+    print "Invalid pixel coordinates"
+    print "Raster dimensions are %d x %d" % (ds.RasterXSize + 1, ds.RasterYSize + 1)
+    sys.exit(1)
+
+band = ds.GetRasterBand(nband)
+if band is None:
+    sys.exit('Cannot access band %d', nband)
+
+# Pixel index is 0-based
+pixel = band.ReadRaster(x - 1, y - 1, 1, 1, 1, 1)
+
+fmt = pt2fmt(band.DataType)
+pixval = struct.unpack(fmt, pixel)
+
+print "Pixel value -> %s" % str(pixval[0])


Property changes on: spike/wktraster/scripts/pixval.py
___________________________________________________________________
Name: svn:executable
   + *