1

I'm trying to merge some rasters with gdalbuildvrt in a python script:

rasters = glob.glob('/{0}/ndvi_masked/*.tif'.format(path))

gdal_cmd = 'gdalbuildvrt -q -vrtnodata "0" -overwrite {0}.vrt'.format(ndvi_name)

for pix in rasters:
    gdal_cmd += ' {0}'.format(pix)

subprocess.call(gdal_cmd, shell=True)

gdal_cmd = 'gdal_translate -of GTiff %s.vrt  %s_clip.tif' % (ndvi_name, ndvi_name)

subprocess.call(gdal_cmd, shell=True)

But the result is really weird, cause I losted some pixels as you can see on the 2nde image below.

All displayed rasters All displayed rasters

Merge raster Merge raster

  • I tried with gdal_merge.py and the result is the same. Does somebody have an idea? – Tim C. Aug 7 '18 at 13:31
  • 3
    Could you share some small dataset for testing? – user30184 Aug 7 '18 at 14:47
  • Perhaps you need to specify -srcnodata rather than -vrtnodata – mikewatt Aug 7 '18 at 22:37
2

I found a solution who works perfectly. I added this piece of code before my first code:

rasters = glob.glob('/{0}/ndvi_clip/*.tif'.format(path))

for pix in rasters:
    gdal_cmd = 'gdal_translate -a_nodata nan {0} {1}/{2}_{3}.tif'.format(pix, noNaN_path, ndvi_name, rasters.index(pix))
    subprocess.call(gdal_cmd, shell=True)

I don't know why, but nan values in my raster weren't real nodata. With this command, I convert nan to nodata.

Here's the doc of this command: gdal_translate

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