gpt.py

#!/usr/bin/env python
#==============================================================================
#                         <gpt.py>
#==============================================================================
# Project   : Co-ReSyF
# Company   : Deimos Engenharia
# Component : Co-ReSyF Tools (snap command line api)
# Language  : Python (v.2.7)
#------------------------------------------------------------------------------
# Scope : (see the following docstring)
# Usage : ---
#==============================================================================
# $LastChangedRevision:  $:
# $LastChangedBy:  $:
# $LastChangedDate:  $:
#==============================================================================

'''
This module is used to run the gpt executable in batch-mode.

'''

''' SYSTEM MODULES '''
import os
import subprocess



def parameter(prefix, value):
    f = ("-%s=\"%s\"" if isinstance(value, basestring) else "-%s=%s")
    return f % (prefix, value)


def call_gpt(operator, source, target, options):
    # ------------------------------------#
    # Building gpt command line #
    # ------------------------------------#
    gpt_options = ' '.join([parameter(key, value) for key, value in options.items() if value is not None])
    targetopt = ("-t \"%s\"" % target if target else "")
    gpt_command = "gpt %s -f GeoTIFF %s -Ssource=\"%s\" %s" % (operator, targetopt, source, gpt_options)  
    # ------------------------------------#
    #    Run gpt command line   #
    # ------------------------------------#
    print ('\n invoking: ' + gpt_command)
    try:
        process = subprocess.Popen(gpt_command,
                                   shell=True,
                                   stdin=subprocess.PIPE,
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE, )
        # Reads the output and waits for the process to exit before returning
        stdout, stderr = process.communicate()
        print (stdout)
        if stderr:
            raise Exception(stderr)  # or  if process.returncode:
        if 'Error' in stdout:
            raise Exception()
    except Exception, message:
        print(str(message))
        # sys.exit(1)  # or sys.exit(process.returncode)
    
    # Change output name (dummy resolution to solve SNAP bug of automatically adding extension)
#    os.rename(target + ".tif", target)