Python GDAL Merge Issue: gdal_merge.py

Question

I am having a Merging issue with the GDAL python library. I am using gdal_merge.pylink
My issue is when I merge two rasters NoData value of one raster overlaps the other data resulting in not a proper raster image.
For example, in the raster images below (left images) if I merge these 4 images labeled as 1,2,3,4 I should get the merged raster image as the right-sided image.
 
But, the merged image I am getting looks like this (image below):
(Note: Image labeled 1,2 and 3 are merged properly. It's only when we merged them with image labeled 4, it's not properly merging.)

If anyone knows, how to resolve this issue then it'll be a great help to me. Thanks in advance.

Nathan Thomas · Answer

Are you using the -n parameter? If not, nodata values will be included in your mosaic.
GDAL will ignore nodata values if you specify this and will mosaic data without overlapping nodata areas included.
Note (update from OP): np.nan may not work as a nodata value
For example:
gdal_merge.py -n 0 -o output.tif input1.tif input2.tif

You will need to know the nodata value and make sure it is the same in each image

Python GDAL Merge Issue: gdal_merge.py

One Answer

Add your own answers!

Ask a Question