[Gdal-dev] rgb2pct.py question
Frank Warmerdam
warmerdam at pobox.com
Tue Jun 1 09:27:17 EDT 2004
bartvde at xs4all.nl wrote:
> Hi list,
>
> I have been using rgb2pct.py recently. My input files are compressed TIFF
> with TFW files. The geoTIFF files that get written don't have the correct
> coordinates in them. Is there any way to have the rgb2pct.py read the
> extents from the TFW files, or any way to update the GeoTiff files with
> the right extents from the TFW files?
>
> Also, is my impression correct that the GeoTIFF files written are totally
> uncompressed?
Bart,
I am somewhat surprised to see that rgb2pct.py does not currently make any
attempt to preserve the georeferencing, or projection of the source image.
I have corrected this in CVS, and attached a new version to this email.
In general the python scripts like rgb2pct.py aren't very sophisticated
and don't offer the ability to set output creation options like those used
to control compression. So you would need to use gdal_translate with the
"-co COMPRESS=DEFLATE" or something similar to re-compress the data after
processing.
Ideally the various python scripts should be updated to include more of
this sort of control.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
-------------- next part --------------
#!/usr/bin/env python
#******************************************************************************
# $Id: rgb2pct.py,v 1.5 2004/06/01 13:24:09 warmerda Exp $
#
# Name: rgb2pct
# Project: GDAL Python Interface
# Purpose: Application for converting an RGB image to a pseudocolored image.
# Author: Frank Warmerdam, warmerdam at pobox.com
#
#******************************************************************************
# Copyright (c) 2001, 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: rgb2pct.py,v $
# Revision 1.5 2004/06/01 13:24:09 warmerda
# Added step to preserve georeferencing.
#
# Revision 1.4 2004/04/02 17:40:44 warmerda
# added GDALGeneralCmdLineProcessor() support
#
# Revision 1.3 2003/05/28 19:47:34 warmerda
# upgrade progress reporting
#
# Revision 1.2 2002/12/04 15:49:13 warmerda
# re-enable cleanup, and fix color count support
#
# Revision 1.1 2001/01/22 22:34:28 warmerda
# New
#
#
import gdal
import sys
import os.path
def Usage():
print 'Usage: rgb2pct.py [-n colors] [-of format] source_file dest_file'
sys.exit(1)
# =============================================================================
# Mainline
# =============================================================================
color_count = 256
format = 'GTiff'
src_filename = None
dst_filename = None
gdal.AllRegister()
argv = gdal.GeneralCmdLineProcessor( sys.argv )
if argv is None:
sys.exit( 0 )
# Parse command line arguments.
i = 1
while i < len(argv):
arg = argv[i]
if arg == '-of':
i = i + 1
format = argv[i]
elif arg == '-n':
i = i + 1
color_count = int(argv[i])
elif src_filename is None:
src_filename = argv[i]
elif dst_filename is None:
dst_filename = argv[i]
else:
Usage()
i = i + 1
if dst_filename is None:
Usage()
# Open source file
src_ds = gdal.Open( src_filename )
if src_ds is None:
print 'Unable to open ', src_filename
sys.exit(1)
if src_ds.RasterCount < 3:
print '%s has %d bands, need 3 for inputs red, green and blue.' \
% src_ds.RasterCount
sys.exit(1)
# Ensure we recognise the driver.
dst_driver = gdal.GetDriverByName(format)
if dst_driver is None:
print '"%s" driver not registered.' % format
sys.exit(1)
# Generate the median cut PCT
ct = gdal.ColorTable()
err = gdal.ComputeMedianCutPCT( src_ds.GetRasterBand(1),
src_ds.GetRasterBand(2),
src_ds.GetRasterBand(3),
color_count, ct,
callback = gdal.TermProgress,
callback_data = 'Generate PCT' )
# Create the working file. We have to use TIFF since there are few formats
# that allow setting the color table after creation.
if format == 'GTiff':
tif_filename = dst_filename
else:
tif_filename = 'temp.tif'
gtiff_driver = gdal.GetDriverByName( 'GTiff' )
tif_ds = gtiff_driver.Create( tif_filename,
src_ds.RasterXSize, src_ds.RasterYSize, 1)
tif_ds.GetRasterBand(1).SetRasterColorTable( ct )
# ----------------------------------------------------------------------------
# We should copy projection information and so forth at this point.
tif_ds.SetProjection( src_ds.GetProjection() )
tif_ds.SetGeoTransform( src_ds.GetGeoTransform() )
# ----------------------------------------------------------------------------
# Actually transfer and dither the data.
err = gdal.DitherRGB2PCT( src_ds.GetRasterBand(1),
src_ds.GetRasterBand(2),
src_ds.GetRasterBand(3),
tif_ds.GetRasterBand(1),
ct,
callback = gdal.TermProgress,
callback_data = 'Generate PCT' )
tif_ds = None
if tif_filename <> dst_filename:
tif_ds = gdal.Open( tif_filename )
dst_driver.CreateCopy( dst_filename, tif_ds )
tif_ds = None
gtiff_driver.Delete( tif_filename )
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