[GRASS-user] script in python

[Jose A. Ruiz-Arias]

Hi Gabriele,

I suggest to try

grass.run_command('v.buffer','input = vect_1','output = 
buffer_200m','buffer= 200')

assuming that grass.run_command is a wrapper to subprocess.popen or so.
Specifically, you could try

import subprocess
vbuffer=subprocess.Popen('v.buffer', 'input=vect_1', 
'output=buffer_200m', 'buffer=200')
retcode=vbuffer.wait()

within the proper GRASS environment session. Read Python's Reference 
Manual regarding subprocess

Cheers,
Jose

Gabriele Nolè escribió:
> Hi Glynn.	
> I use ubuntu 8.10 and grass64 svn
> I made the changes based on your claims.
> This is my code: 
> -------------------------------------------------------------------------------------
> def main():
> 	# con = assegno le variabili
> 	vect1 = options['vect_1']
> 	vect2 = options['vect_2']
> 	vect3 = options['vect_3']	
> 
> 	grass.run_command('v.buffer', input = vect_1, output = buffer_200m, buffer
> = 200)         
> 
> if __name__ == "__main__":
>             options, flags = grass.parser()
>             main()
> ---------------------------------------------------------------------------------------------
> But  if __name__ == "__main__": etc      ...... what is your job? 
> 
> Unfortunately, I made several attempts, but I have an error: 
> Traceback (most recent call last):
>   File "/home/gab/scripts_grass/v.rischio_incendi.py", line
> 75, in <module>
>     main()
>   File "/home/gab/scripts_grass/v.rischio_incendi.py", line
> 70, in main
>     grass.run_command('v.buffer', input = vect_1, output =
> buffer_200m, buffer = 200)
> NameError: global name 'vect_1' is not defined
> 
> I do not know how "to treat" the output of the v.buffer (in this case,
> buffer_200m).
> 
> Thanks Glynn
> 
> Gabriele
> 
> PS
> With grass 7 will work scripts in bash?
> 
> 
> 
> Glynn Clements wrote:
>>
>> Gabriele Nolè wrote:
>>
>>> I'm trying to write a little script in python but I have difficulty (I
>>> know
>>> a bit the bash).
>>> The script must first run a buffer and then some overlay.	
>>> I am following the wiki and seeing some script as v.type.py,
>>> color_table.py
>>> etc. ..
>>> Now I am at this point:
>>>     print "Value of GIS_OPT_vect_1: %s" % os.getenv("GIS_OPT_vect_1")
>>>     print "Value of GIS_OPT_vect_2:  %s" % os.getenv("GIS_OPT_vect_2")
>>>     print "Value of GIS_OPT_vect_3:    %s" % os.getenv("GIS_OPT_vect_3")
>>> if __name__ == "__main__":
>>>     args = ""
>>>     for arg in sys.argv:
>>>         args += arg+" "
>>>     try:
>>>         if ( sys.argv[1] != "@ARGS_PARSED@" ):
>>>             os.system("g.parser %s " % (args))
>>>     except IndexError:
>>>         os.system("g.parser %s" % (args))
>>>
>>>     if sys.argv[1] == "@ARGS_PARSED@":
>>>         main(); 
>> Look at the Python scripts in 7.0 for reference:
>>
>> http://trac.osgeo.org/grass/browser/grass/trunk/scripts
>>
>> Explicitly calling g.parser and reading GIS_OPT_* environment
>> variables is no longer necessary (or desirable; g.parser may
>> eventually be changed to use some other mechanism for passing data
>> back to the script). Instead:
>>
>> 	def main():
>> 	    vect1 = options['vect_1']
>> 	    vect2 = options['vect_2']
>> 	    vect3 = options['vect_3']
>> 	
>> 	    ...
>> 	
>> 	if __name__ == "__main__":
>> 	    options, flags = grass.parser()
>> 	    main()
>>
>>>     grass.run_command('v.buffer', input = vect_1 output = buffer_200m
>>> buffer = 200)
>> You need commas between arguments, i.e.:
>>
>>     grass.run_command('v.buffer', input = vect_1, output = buffer_200m,
>> buffer = 200)
>>
>>>    # or grass.exec_command ?
>> Usually not; exec_command will effectively terminate the script. Use
>> run_command if you want control to return to the script once the
>> command completes.
>>
>> -- 
>> Glynn Clements <glynn at gclements.plus.com>
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>
>>
> 

-- 
José A. Ruiz-Arias
Solar Radiation and Atmosphere Modelling Group
http://www.ujaen.es/investiga/tep220
Physics Department, University of Jaén
Campus Lagunillas, Building A3 066
23071 Jaén Spain
Tlf: +34 953 212 474
Fax: +34 953 212 838