Merge raster data with GDAL in Python

This tutorial explains how to merge a bunch of raster tiles from the same directory to a single geotiff file using GDAL in Python. There are two options to merge raster data with GDAL: 1) run gdal_merge.py with subprocess 2) build a virtual mosaic of all raster files and convert that to geotiff.
GDAL/OGR Python API: gdal.org/python/
Code:
from osgeo import gdal
import glob
import subprocess
list all files in directory that match pattern
demList = glob.glob("dem[0-9][0-9].tif")
print(demList)
gdal_merge
cmd = "gdal_merge.py -ps 10 -10 -o mergedDEM.tif"
subprocess.call(cmd.split()+demList)
build virtual raster and convert to geotiff
vrt = gdal.BuildVRT("merged.vrt", demList)
gdal.Translate("mergedDEM2.tif", vrt, xRes = 10, yRes = -10)
vrt = None

[@hubertkanyamahanga2095]

Thanks for the short tutorial. Here is an alternative: gdal_merge.py -o large_output_raster.tif your/raster/folder/*.tif Make sure you have gdal installed and run it in terminal.

[@malcolmcoull1240]

Fantastic, thank you so much. I have spent much longer than I should working out how to loop this through an entire directory of images, which will save so loads of time in future.

[@chaoli932]

You must a good researcher in RS. Thanks for your help

[@hadikarimi2818]

How did you merge python to QGIS to work instantly and show the result? Can you please let me know if there is a video for it. Thank you

[@rubencrespo1720]

I don't understand the subprocess.call function. I understand that you concatenate the cmd with the DMElist, but why is the split needed. Awesome tutorial, thanks!

[@saeidshamsaliei2536]

Thank you very much

[@MrBreazyyy]

Is there a way to add multiple geotiff files( like markers or houses) on an other geotiff file?

[@sarahtulip4714]

Hi, the output file size becomes too large after merging. Could you please explain how to fix this?

[@shubhamkedar508]

Can you make video on custom dataset of raster(geotiff image)dataset.

[@isabelahorta3063]

Hiii, I'm using the virtual raster method but not all the tifs are being merged :( what should I do?

[@livmaritharstad1629]

Great video! I've merged a couple of datasets with no issue, but now I get this error:
ERROR 1: ZIPDecode:Decoding error at scanline 0
ERROR 1: TIFFReadEncodedTile() failed.
ERROR 1: \\Path to this file...\DTM_1km_6159_636.tif, band 1: IReadBlock failed at X offset 0, Y offset 0: TIFFReadEncodedTile() failed.
the data is from Denmark and I've got different offset values like x=6, 1 or 8 and y=5 or 6
I've been stuck on this problem for a while and tried all the solutions I've found on the internet, have you encountered this problem before?

[@sabazehra1412]

Hi, thank you for the tutorial, I am new to python and I am getting the error (OSError: [WinError 193] %1 is not a valid Win32 application) while running the command of subprocess.call(cmd.split()+demlist). Can you please help me out? thanks

[@kmehour]

I'm having the same issue, did you find the answer to that by any chance ?

[@sabazehra1412]

@@kmehour No sorry I could not figure it out, but I tried the second method as mentioned in this video and it worked well.

[@aryanirvaan]

The solution to this problem is subprocess.call(cmd.split()+demlist) write subprocess.call([cmd.split()+demlist], shell=True)

[@aryanirvaan]

@@kmehour Please read the comment.

[@Maze160]

@@aryanirvaan Thanks! Helped me solve the problem.
Now I get the error: "TypeError: expected str, bytes or os.PathLike object, not list" did you happen to encounter that as well?

[@yergenabdrakhmanov8243]

Where did you get these pictures?