#!/usr/bin/env python
###############################################################################
# $Id: tolatlong.py,v 1.3 2005/04/22 08:19:00 dron Exp $
#
# Project:  GDAL Python samples
# Purpose:  Script to read coordinate system and geotransformation matrix
#	    from input file and report latitude/longitude coordinates for the
#	    specified pixel.
# Author:   Andrey Kiselev, dron@remotesensing.org
#
###############################################################################
# Copyright (c) 2003, Andrey Kiselev <dron@remotesensing.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.
###############################################################################
# 
#  $Log: tolatlong.py,v $
#  Revision 1.3  2005/04/22 08:19:00  dron
#  Fixed mess with the lat/long variables naming.
#
#  Revision 1.2  2003/09/01 15:04:43  dron
#  More comments, report improved.
#
#  Revision 1.1  2003/07/03 10:27:23  dron
#  New.
#
#

import gdal
from gdalconst import *
import osr
import sys

# =============================================================================
def Usage():
    print
    print 'Read coordinate system and geotransformation matrix from input'
    print 'file and report latitude/longitude coordinates for the center'
    print 'of the specified pixel.'
    print
    print 'Usage: tolatlong.py pixel line infile'
    print
    sys.exit( 1 )

# =============================================================================

infile = None
pixel = None
line = None

# =============================================================================
# Parse command line arguments.
# =============================================================================
i = 1
while i < len(sys.argv):
    arg = sys.argv[i]

    if pixel is None:
	pixel = float(arg)

    elif line is None:
	line = float(arg)

    elif infile is None:
	infile = arg

    else:
	Usage()

    i = i + 1

if infile is None:
    Usage()
if pixel is None:
    Usage()
if line is None:
    Usage()

# Open input dataset
indataset = gdal.Open( infile, GA_ReadOnly )

# Read geotransform matrix and calculate ground coordinates
geomatrix = indataset.GetGeoTransform()
X = geomatrix[0] + geomatrix[1] * pixel + geomatrix[2] * line
Y = geomatrix[3] + geomatrix[4] * pixel + geomatrix[5] * line

# Shift to the center of the pixel
X += geomatrix[1] / 2.0
Y += geomatrix[5] / 2.0

# Build Spatial Reference object based on coordinate system, fethed from the
# opened dataset
srs = osr.SpatialReference()
srs.ImportFromWkt(indataset.GetProjection())

srsLatLong = srs.CloneGeogCS()
ct = osr.CoordinateTransformation(srs, srsLatLong)
(long, lat, height) = ct.TransformPoint(X, Y)

# Report results
print 'pixel: %g\t\t\tline: %g' % (pixel, line)
print 'latitude: %fd\t\tlongitude: %fd' % (lat, long)
print 'latitude: ', gdal.DecToDMS(lat, 'Lat', 2), \
    '\tlongitude: ', gdal.DecToDMS(long, 'Long', 2)

