Inserting nodata value using GDAL?

Question

I'd like to edit the nodata values in several raster files, but big number of these file doesn't have any nodata value defined, there is nothing to edit. I'v tried the gdal_translate -a_nodata command but it'as not working for me. As I understand this command is only suitable for changing an already defined nodata value.

Any ideas?

Answer 1

Python works pretty well for this:

from osgeo import gdal
from osgeo.gdalconst import GA_Update
filename = 'somefile.tif'
nodata = 0
# open the file for editing
ras = gdal.Open(filename, GA_Update)
# loop through the image bands
for i in range(1, ras.RasterCount + 1):
    # set the nodata value of the band
    ras.GetRasterBand(i).SetNoDataValue(nodata)
# unlink the file object and save the results
ras = None

Answer 2

if you have gdal in python (you can get the .whl file here if needed), you should be able to do the following:

import gdal
ds = gdal.Open(r"Path\To\Your\File.extension",1) # The 1 means that you are opening the file to edit it)
rb = ds.GetRasterBand(1) #assuming your raster has 1 band. 
rb.SetNoDataValue(YOUR VALUE HERE)
rb= None 
ds = None