Python – How to Read .tif Image Coordinates

geotiff-tiffpython

I want to read the coordinates of a .tif file in order to use them inside Python code. Although gdalinfo command on Ubuntu terminal displays a lot of information, it is useless since I cannot use them inside larger Python code, unless I put them manually, which does not work on my occasion. I found and use this code:

import exifread
# Open image file for reading (binary mode)
f = open('image.tif', 'rb')

# Return Exif tags
tags = exifread.process_file(f)

# Print the tag/ value pairs
for tag in tags.keys():
    if tag not in ('JPEGThumbnail', 'TIFFThumbnail', 'Filename', 'EXIF MakerNote'):
        print("Key: %s, value %s" % (tag, tags[tag]))

from here: https://stackoverflow.com/questions/46477712/reading-tiff-image-metadata-in-python

The problem that I face is that I cannot get all the coordinates or at least 2 critical of them (such as upper left corner and right down corner), so that I can calculate all 4. What I get with the above mentioned code is only the upper left corner's coordinates… How can I fix that? How can I get and the right down corner's coordinates?

Best Answer

Rasterio would be an easy choice to get the information you need via Python. This code gets the bounding geometry of a geotiff.

import rasterio
dataset = rasterio.open('/home/gerry/Drone/MedTest/referencedimages/warped_DJI_0001.TIF')
#left edge
print(dataset.bounds[0])
#bottom edge
print(dataset.bounds[1])
#right edge
print(dataset.bounds[2])
#top edge
print(dataset.bounds[3])

Related Solutions

GeoTIFF TIFF Tags – Change or Delete GeoTIFF Tags in TIFF File

I've found an answer on the project-page of exiftool itself. Hereafter, I'll summarize what I found out with the kind help of the page-author Phil Harvey.

To copy all GeoTiff tags from one file to another, do this:

exiftool -tagsfromfile SRCFILE -GeoTiffDirectory -GeoTiffDoubleParams -GeoTiffAsciiParams DSTFILE

That does the trick. I assume that those pseudo-TAGs are split-up by exiftools in all sub-GeoTiff-TAGs, because other tools in python print these out as TAGs with their associated numbers. Python packages which are able to display these general 3 Geotiff-TAGs

('34735') 'GeoKeyDirectoryTag'
('34736') 'GeoDoubleParamsTag'
('34737') 'GeoAsciiParamsTag'

are for example:

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

An example output using PILLOW (PIL) via my python script applied on an example TIFF would be:

...
** GENERIC APPROACH USING PILLOW-package **

TAG number: '254'
TAG name: 'NewSubfileType'
TAG value: '(0,)'

TAG number: '256'
TAG name: 'ImageWidth'
TAG value: '(2388,)'

TAG number: '257'
TAG name: 'ImageLength'
TAG value: '(1651,)'

TAG number: '258'
TAG name: 'BitsPerSample'
TAG value: '(8,)'

TAG number: '259'
TAG name: 'Compression'
TAG value: '(1,)'

TAG number: '262'
TAG name: 'PhotometricInterpretation'
TAG value: '(1,)'

TAG number: '270'
TAG name: 'ImageDescription'
TAG value: '('{"shape": [1651, 2388]}',)'

TAG number: '274'
TAG name: 'Orientation'
TAG value: '(1,)'

TAG number: '277'
TAG name: 'SamplesPerPixel'
TAG value: '(1,)'

TAG number: '278'
TAG name: 'RowsPerStrip'
TAG value: '(1651,)'

TAG number: '282'
TAG name: 'XResolution'
TAG value: '((1, 1),)'

TAG number: '283'
TAG name: 'YResolution'
TAG value: '((1, 1),)'

TAG number: '284'
TAG name: 'PlanarConfiguration'
TAG value: '(1,)'

TAG number: '296'
TAG name: 'ResolutionUnit'
TAG value: '(1,)'

TAG number: '305'
TAG name: 'Software'
TAG value: '('tifffile.py',)'

TAG number: '339'
TAG name: 'SampleFormat'
TAG value: '(1,)'

TAG number: '33550'
TAG name: 'ModelPixelScaleTag'
TAG value: '(30.0, 30.0, 0.0)'

TAG number: '33922'
TAG name: 'ModelTiepointTag'
TAG value: '(0.0, 0.0, 0.0, 737125.0, 4328658.0, 0.0)'

TAG number: '34735'
TAG name: 'GeoKeyDirectoryTag'
TAG value: '(1, 1, 0, 15, 1024, 0, 1, 1, 1025, 0, 1, 1, 1026, 34737, 266, 0, 2048, 0, 1, 4269, 3072, 0, 1, 32767, 3073, 34737, 197, 266, 3074, 0, 1, 32767, 3075, 0, 1, 11, 3076, 0, 1, 9001, 3078, 34736, 1, 0, 3079, 34736, 1, 1, 3081, 34736, 1, 2, 3082, 34736, 1, 3, 3083, 34736, 1, 4, 3088, 34736, 1, 5)'

TAG number: '34736'
TAG name: 'GeoDoubleParamsTag'
TAG value: '(29.5, 45.5, 23.0, 0.0, 0.0, -96.0)'

TAG number: '34737'
TAG name: 'GeoAsciiParamsTag'
TAG value: '('IMAGINE GeoTIFF Support\nCopyright 1991 - 2001 by ERDAS, Inc. All Rights Reserved\n@(#)$RCSfile: egtf.c $ $Revision: 1.11.2.3 $ $Date: 2004/11/24 09:12:56EST $\nProjection Name = USA_Contiguous_Albers_Equal_Area_Conic_USGS_version\nUnits = meters\nGeoTIFF Units = meters|IMAGINE GeoTIFF Support\nCopyright 1991 - 2001 by ERDAS, Inc. All Rights Reserved\n@(#)$RCSfile: egtf.c $ $Revision: 1.11.2.3 $ $Date: 2004/11/24 09:12:56EST $\nProjection = Albers Conical Equal Area|',)'
...

To change the Projection tag alone, you would currently have to manually edit the GeoTiffDirectory data.

First write the (binary) data to a file:

exiftool -geotiffdirectory -b FILE.tif > out.dat

Then find the offset of e.g. the Projection value, like:

exiftool FILE.tif -v3 | grep -A 2 Projection -
  | 9)  Projection = 16017
  |     - Tag 0x0c02 (2 bytes, int16u[1]):
  |         0056: 3e 91                                           [>.]

--> Edit bytes 0x56 and 0x57 in out.dat to change to whatever projection you want, then put the modified GeoTiff directory back into the TIFF file:

exiftool "-geotiffdirectory<=out.dat" FILE.tif

Nevertheless, it is important to note, that changing the 3 crucial summarizing GeoTIFF-Tags, instead of trying to manipulate one of the single GeoTIFF-TAGs via modifying the above-mentioned binary-file and reassign it to the TIFF in question, could be more effective.

For the sake of completion, these 3 GeoTIFF-Tags were:

('34735') 'GeoKeyDirectoryTag'
('34736') 'GeoDoubleParamsTag'
('34737') 'GeoAsciiParamsTag'

Nevertheless, it could be possible that by changing just one specific GeoTIFF-Tag within the binary-file is also going to update as a result the 3 crucial GeoTIFF-summary-Tags in new TIFF. I haven't tried that out yet.

If you have to add some additional information or experiences with these approaches, which work for you etc., let me know.

Cheers

Best Answer

Related Solutions

GeoTIFF TIFF Tags – Change or Delete GeoTIFF Tags in TIFF File

Related Question