The geotiff format driver assigns all bands the same nodata value, even if only a single band was specified with bandN.SetNoDataValue Also see http://www.nabble.com/python%3A-setting-nodata-affects-all-bands-td14303097.html
----- gdalsetnull.py -----
import gdal
import sys
import os.path
if len(sys.argv) < 2:
print "Usage: gdalsetnull.py raster_file null_value"
sys.exit(1)
input = sys.argv[1]
null_value = sys.argv[2]
dataset = gdal.Open( input, gdal.GA_Update )
if dataset is None:
print 'Unable to open', input, 'for writing'
sys.exit(1)
b1 = dataset.GetRasterBand(1)
b2 = dataset.GetRasterBand(2)
b3 = dataset.GetRasterBand(3)
print 'Initial nodata:\t', b1.GetNoDataValue(), b2.GetNoDataValue(), b3.GetNoDataValue()
b1.SetNoDataValue( float(null_value) )
print 'Output nodata:\t', b1.GetNoDataValue(), b2.GetNoDataValue(), b3.GetNoDataValue()
---------------------------
Results:
python gdalsetnull.py nodata-test.tif 0
Initial nodata: 46.0 46.0 46.0
Output nodata: 0.0 0.0 0.0
