Use libgeotiff to change or delete GeoTiff-TAGs

[AndreasLuckert]

Dear community,

I'm using Linux Lubuntu 18.04 with exiftool command line and python libraries in order to modify TIFF-Tags of a land cover classification GeoTIFF-file. I wonder if using libgeotiff can make a difference. So far, I don't even know how to start using it, since I haven't found very telling examples for my specific task (change or delete GeoTiff-TAGs).

As the Python libraries

import exifread
import PIL
import tifffile as tf
from skimage.external import tifffile as sk_tf

don't even list the GeoTiff tags, since they are "blind on that eye", I found that exiftool lists, but cannot change them.

The output of my example file, using exiftool in the terminal, is: Input: exiftool -D -G -a -u -U -f "newfile.tif" Output:

[ExifTool]          - ExifTool Version Number         : 10.80
[File]              - File Name                       : newfile.tif
[File]              - Directory                       : .
[File]              - File Size                       : 1503 kB
[File]              - File Modification Date/Time     : 2019:12:19 17:32:17+01:00
[File]              - File Access Date/Time           : 2019:12:19 17:32:17+01:00
[File]              - File Inode Change Date/Time     : 2019:12:19 17:32:17+01:00
[File]              - File Permissions                : rw-rw-r--
[File]              - File Type                       : TIFF
[File]              - File Type Extension             : tif
[File]              - MIME Type                       : image/tiff
[File]              - Exif Byte Order                 : Little-endian (Intel, II)
[File]              - Current IPTC Digest             : 79ffcf282ca6974ff99640a7421b40b7
[EXIF]            256 Image Width                     : 1148
[EXIF]            257 Image Height                    : 1337
[EXIF]            258 Bits Per Sample                 : 8
[EXIF]            259 Compression                     : Uncompressed
[EXIF]            262 Photometric Interpretation      : RGB Palette
[EXIF]            273 Strip Offsets                   : (Binary data 1390 bytes, use -b option to extract)
[EXIF]            274 Orientation                     : Horizontal (normal)
[EXIF]            277 Samples Per Pixel               : 1
[EXIF]            278 Rows Per Strip                  : 7
[EXIF]            279 Strip Byte Counts               : (Binary data 954 bytes, use -b option to extract)
[EXIF]            282 X Resolution                    : 1
[EXIF]            283 Y Resolution                    : 1
[EXIF]            284 Planar Configuration            : Chunky
[EXIF]            296 Resolution Unit                 : None
[EXIF]            305 Software                        : IMAGINE TIFF Support.Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved.@(#)$RCSfile: etif.c $ $Revision: 1.11 $ $Date$
[EXIF]            320 Color Map                       : (Binary data 1536 bytes, use -b option to extract)
[EXIF]            339 Sample Format                   : Unsigned
[EXIF]          33550 Pixel Scale                     : 30 30 0
[EXIF]          33922 Model Tie Point                 : 0 0 0 1514925 1583985 0
[IPTC]             25 Keywords                        : word
[IPTC]              0 Application Record Version      : 4
[GeoTiff]           1 Geo Tiff Version                : 1.1.0
[GeoTiff]        1024 GT Model Type                   : Projected
[GeoTiff]        1025 GT Raster Type                  : Pixel Is Area
[GeoTiff]        1026 GT Citation                     : IMAGINE GeoTIFF Support.Copyright 1991 - 2001 by ERDAS, Inc. All Rights Reserved.@(#)$RCSfile: egtf.c $ $Revision: 1.11.2.3 $ $Date: 2004/11/24 09:12:56EST $.Projection Name = USA_Contiguous_Albers_Equal_Area_Conic_USGS_version.Units = meters.GeoTIFF Units = meters
[GeoTiff]        2048 Geographic Type                 : NAD83
[GeoTiff]        3072 Projected CS Type               : User Defined
[GeoTiff]        3073 PCS Citation                    : IMAGINE GeoTIFF Support.Copyright 1991 - 2001 by ERDAS, Inc. All Rights Reserved.@(#)$RCSfile: egtf.c $ $Revision: 1.11.2.3 $ $Date: 2004/11/24 09:12:56EST $.Projection = Albers Conical Equal Area
[GeoTiff]        3074 Projection                      : User Defined
[GeoTiff]        3075 Proj Coord Trans                : Albers Equal Area
[GeoTiff]        3076 Proj Linear Units               : Linear Meter
[GeoTiff]        3078 Proj Std Parallel 1             : 29.5
[GeoTiff]        3079 Proj Std Parallel 2             : 45.5
[GeoTiff]        3081 Proj Nat Origin Lat             : 23
[GeoTiff]        3082 Proj False Easting              : 0
[GeoTiff]        3083 Proj False Northing             : 0
[GeoTiff]        3088 Proj Center Long                : -96
[Composite]         - Image Size                      : 1148x1337
[Composite]         - Megapixels                      : 1.5

Now, I'd like to change/delete the GeoTiff-TAG "Projection", which throws the following warning message without changing anything: Input: exiftool "-Projection=" "newfile.tif" Output: Warning: Sorry, Projection is not writable. Nothing to do.

Next, I found the following documentation of this very webpage: https://exiftool.org/TagNames/GeoTiff.html

It states, among other details, the following:

GeoTIFF tags are not writable individually, but they may be copied en mass via the block tags GeoTiffDirectory, GeoTiffDoubleParams and GeoTiffAsciiParams.

Is there any possibility to change/rename/delete a GeoTiff-TAG of choice via command line tolls such as libgeotiff, exiftools (as stated above in my attempt), or gdal etc.? I'm quite desparate already, since I've invested a lot of time in finding a possiblity, but so far no avail.

Thanks in advance for helping me out. Kind regards, Andreas

[rouault]

No need to spam both GDAL and libgeotiff with same request. github issues are not a support channel. Thanks

[AndreasLuckert]

Alright, I'm sorry. I didn't know that those posts are available and visible everywhere on GitHub. I'm knew to GitHub anyway.

Well, as far as the content is concerned, if there is any chance to change GeoTiff-TAGs via libgeotiff, let me know, please. Thanks in advance Cheers