Colab - Split big tiff file using GDAL

Question

I'm trying to split a huge tiff file into tiles using gdal on Colab.

My google drive is mounted and I can read and write from / into it.

The code is taken from this answer:

com_string = "gdal_translate -of GTIFF -srcwin" + ...
os.system(com_string)

The cell completes but no new files show up on the drive. Any ideas or another way to achieve the splitting of the file?

Answer 1

This answer gives a suggestion:

You would need to come up with the pixel/line locations or corner coordinates and then loop over the values with gdal_translate.

import os, sys
from osgeo import gdal

dset = gdal.Open(sys.argv[1])

width = dset.RasterXSize
height = dset.RasterYSize

print width, 'x', height

tilesize = 5000

for i in range(0, width, tilesize):
    for j in range(0, height, tilesize):
        w = min(i+tilesize, width) - i
        h = min(j+tilesize, height) - j
        gdaltranString = "gdal_translate -of GTIFF -srcwin "+str(i)+", "+str(j)+", "+str(w)+", " \
            +str(h)+" " + sys.argv[1] + " " + sys.argv[2] + "_"+str(i)+"_"+str(j)+".tif"
        os.system(gdaltranString)

This, of course, relies on your gdal installation working properly. If the above doesn't work (you get no files still) try first running it in a location that isn't a mounted Google Drive. If that works, you know the problem is with your mounting. If not, next I would check to make sure you are getting the input image you are expecting with something like plt.imshow(your_source_image). If you see the image, then move on. If not, your source image is either missing or the path is wrong.

If it still doesn't work, I'd suspect it is a problem with your gdal installation. In that case I would first try a very simple function and make sure it gives the result you expect. You can also try running something else on Collab and make sure that works.