[GRASS-user] Trying python scripts.

[Marcello Gorini]

Dear all,

This is kind of my first e-mail ever to ANY mailing list, so please forgive
me if I don't express myself in the best way. I will improve eventually.
I am a total beginner in python and GRASS (and any other programming
language), so I am trying to run the first examples found in
http://grass.osgeo.org/wiki/GRASS_and_Python.
I managed to run the shaded_relief one OK, but the one with respect to
mapcalc, I couldn't.
I copied a script found in
http://www.mail-archive.com/grass-dev@lists.osgeo.org/msg14669.html
(transcribed below) and tried to run it:

#!/usr/bin/env python

# g.parser demo script for python programing

#%module
#%  description: g.parser test script (python) TUN
#%end
#%flag
#%  key: f
#%  description: A flag
#%end
#%flag
#%  key: n
#%  description: Another flag
#%end
#%option
#%  key: raster1
#%  type: string
#%  gisprompt: old,cell,raster
#%  description: Raster input map
#%  required : yes
#%end
#%option
#%  key: raster2
#%  type: string
#%  gisprompt: old,cell,raster
#%  description: Raster2 input map
#%  required : yes
#%end
#%option
#%  key: output
#%  type: string
#%  gisprompt: new,cell,raster
#%  description: Output
#%  required : yes
#%end

import os
import sys

import grass.script as grass

def main():
    output = options['output']
    raster1 = options['raster1']
    raster2 = options['raster2']
    grass.mapcalc("$out = $rast1 + $rast2", out = output, rast1 = raster1, 
rast2 = raster2)
    if flags['f']:
        print "Flag -f set"
    else:
        print "Flag -f not set"

    if flags['n']:
        print "Flag -n foi definida mas nao devia"
    else:
        print "Flag -n not set- GOOD"      
    print options
    print flags
    return 0

if __name__ == "__main__":
    options, flags = grass.parser()
    sys.exit(main())


It seems to run OK and “100%” is displayed in the GRASS prompt, but when I
tried to display the map, I found out that it wasn't created at all.
Just for you to know, to run the script I simply create it (say
“myscript.py”), give permissions and run it in a GRASS session with the
necessary options: > ./myscript.py output=outmap raster1=map1 raster2=map2
I am using Ubuntu 9.04 64bits and GRASS 6.4.ORC5. 
Can anyone help me?

Best regards,
Marcello Gorini.
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