#!/usr/local/bin/python3.7
# ******************************************************************************
#  $Id: gcps2wld.py 8e263710cb425c4a8b76b1f363b98be41ea0a983 2018-04-30 19:40:20 +1000 Ben Elliston $
#
#  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
#  Copyright (c) 2009-2010, Even Rouault <even dot rouault at mines-paris dot org>
#
#  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.
# ******************************************************************************

import sys

from osgeo import gdal

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 %s' % filename)
    sys.exit(1)

gcps = dataset.GetGCPs()

if gcps is None or not gcps:
    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])
