#!/usr/bin/env python
#******************************************************************************
#  $Id: gcps2wld.py 6687 2004-10-19 20:16:28Z fwarmerdam $
# 
#  Name:     gcps2wld
#  Project:  GDAL Python Interface
#  Purpose:  Translate the set of GCPs on a file into first order approximation
#            in world file format.
#  Author:   Frank Warmerdam, warmerdam@pobox.com
# 
#******************************************************************************
#  Copyright (c) 2002, Frank Warmerdam
# 
#  Permission is hereby granted, free of charge, to any person obtaining a
#  copy of this software and associated documentation files (the "Software"),
#  to deal in the Software without restriction, including without limitation
#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
#  and/or sell copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following conditions:
# 
#  The above copyright notice and this permission notice shall be included
#  in all copies or substantial portions of the Software.
# 
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
#  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
#  DEALINGS IN THE SOFTWARE.
#******************************************************************************
# 
# $Log$
# Revision 1.2  2004/10/19 20:16:28  fwarmerdam
# Fixed up error reporting somewhat.
#
# Revision 1.1  2002/05/07 03:12:25  warmerda
# New
#
#

import gdal
import sys
import os.path

if len(sys.argv) < 2:
    print "Usage: gcps2wld.py source_file"
    sys.exit(1)

    

filename = sys.argv[1]
dataset = gdal.Open( filename )
if dataset is None:
    print 'Unable to open ', filename
    sys.exit(1)

gcps = dataset.GetGCPs()

if gcps is None or len(gcps) == 0:
    print 'No GCPs found on file ' + filename
    sys.exit(1)

geotransform = gdal.GCPsToGeoTransform( gcps )

if geotransform is None:
    print 'Unable to extract a geotransform.'
    sys.exit( 1 ) 

print geotransform[1]
print geotransform[4]
print geotransform[2]
print geotransform[5]
print geotransform[0] + 0.5 * geotransform[1] + 0.5 * geotransform[2]
print geotransform[3] + 0.5 * geotransform[4] + 0.5 * geotransform[5]