Convert i.image.mosaic to Python

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@33601 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/i.image.mosaic/i.image.mosaic.html

@@ -1,7 +1,7 @@
 <H2>DESCRIPTION</H2>
 
 
-<EM>i.image.mosaic</EM> Mosaics up to 4 images or raster maps using map calculator, and extends colormap to range of all images.
+<EM>i.image.mosaic</EM> Mosaics several images or raster maps using map calculator, and extends colormap to range of all images.
 <br>
 
 

scripts/i.image.mosaic/i.image.mosaic.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python
+
+# written by Markus Neteler 18. August 1998 / 20. Jan. 1999
+#            neteler geog.uni-hannover.de
+# mosaic code from Felix Gershunov (Felix spsl.nsc.ru)
+# updated for GRASS 5.7 by Michael Barton 2004/04/05
+# converted to Python by Glynn Clements
+#
+# COPYRIGHT:    (C) 1999,2007,2008 by the GRASS Development Team
+#
+#               This program is free software under the GNU General Public
+#               License (>=v2). Read the file COPYING that comes with GRASS
+#               for details.
+#
+# TODO: - implement g.findfile for 3 and 4 maps (currently only current mapset supported)
+#            [done for 2 maps]
+#       - fix isnull() in r.mapcalc for 3 and 4 maps composites
+#            [done for 2 maps]
+#       - fix color table length (currently only 256 cols supported, make
+#         flexible)
+#            [done for 2 maps]
+#--------------------------------------------------
+
+
+#% Module
+#%  description: Mosaics several images and extends colormap
+#%  keywords: raster, imagery, mosaicking
+#% End
+#% option
+#% key: images
+#% type: string
+#% gisprompt: old,cell,raster
+#% description: maps for mosaic.
+#% required: yes
+#% multiple: yes
+#% end
+#%option
+#% key: output
+#% type: string
+#% gisprompt: new,cell,raster
+#% description: reclass raster output map
+#% required : no
+#%END
+
+import sys
+import os
+import string
+import grass
+
+def copy_colors(fh, map, offset):
+    p = grass.pipe_command('r.colors.out', map = map)
+    for line in p.stdout:
+	f = line.rstrip('\r\n').split(' ')
+	if offset:
+	    if f[0] in ['nv', 'default']:
+		continue
+	    f[0] = str(float(f[0]) + offset)
+	fh.write(' '.join(f) + '\n')
+    p.wait()
+
+def get_limit(map):
+    s = grass.read_command('r.info', flags = 'r', map = map)
+    kv = grass.parse_key_val(s)
+    return float(kv['max'])
+
+def make_expression(i, count):
+    if i > count:
+	return "null()"
+    else:
+	e = make_expression(i + 1, count)
+	return "if(isnull($image%d),%s,$image%d+$offset%d)" % (i, e, i, i)
+
+def main():
+    images = options['images'].split(',')
+    output = options['output']
+
+    if not output:
+	output = '.'.join(images) + '.mosaic'
+
+    count = len(images)
+
+    grass.warning('Do not forget to set region properly to cover all images.')
+
+    offset = 0
+    offsets = []
+    parms = {}
+    for n, img in enumerate(images):
+	offsets.append(offset)
+	parms['image%d' % (n + 1)] = img
+	parms['offset%d' % (n + 1)] = offset
+	offset += get_limit(img) + 1
+
+    grass.message("Mosaicing %d images..." % count)
+
+    t = string.Template("$output = " + make_expression(1, count))
+    print t.template
+    e = t.substitute(output = output, **parms)
+    grass.run_command('r.mapcalc', expression = e)
+
+    #modify the color table:
+    p = grass.feed_command('r.colors', map = output, rules='-')
+    for img, offset in zip(images, offsets):
+	print img, offset
+	copy_colors(p.stdin, img, offset)
+    p.stdin.close()
+    p.wait()
+
+    grass.message("Ready. File %s created." % output)
+
+    # write cmd history:
+    grass.run_command('r.support', map = output, history = os.environ['CMDLINE'])
+
+if __name__ == "__main__":
+    options, flags = grass.parser()
+    main()