How to use gdal to convert HDF multi-band file to a single GeoTiff file?

Question

I have a multi-band HDF file that I want to convert to a single GeoTiff file, using free tools, preferably gdal. I'm trying to use gdal_translate, but I either get back multiple output .tif files, or I get "subdatasets" errors.

When I use the -b flag to specify bands:

gdal_translate -b 1 -b 2 -of GTiff input_image.hdf output_image.tif

I get "subdatasets" errors: "Input file contains subdatasets. Please, select one of them for reading."

And when I use the sds flag:

gdal_translate -sds -of GTiff input_file.hdf output_file.tif

I get back separate .tif files, one for each band in the input file.

How can I convert an HDF file into a single GeoTiff file using gdal?

Answer 1

I also couldn't find a way to do it in one step... but using -sds like you did, followed by a gdal_merge.py -separate should work https://gdal.org/programs/gdal_merge.html#cmdoption-gdaladdo-separate

https://gdal.org/programs/gdal_translate.html#cmdoption-gdal-translate-sds

So this should work for you:

gdal_translate -sds input_file.hdf tmp_outs.tif

gdal_merge.py -separate -o final_output.tif tmp_outs*tif

rm tmp_outs*tif

if your HDF5 subdatasets are different datatypes, specify which output type you want with gdal_merge.py -ot Float32 ...

Just to reference here what those options mean:

-sds

Copy all subdatasets of this file to individual output files. Use with formats like HDF that have subdatasets.



-separate

Place each input file into a separate band.

Answer 2

If you want to extract one band (subdataset) from your HDF file, than you need to specify the SUBDATASET name as part of the gdal_translate command. For instance, in the example described here, it is suggested to do the following:

gdal_translate HDF4_SDS:UNKNOWN:"AMOD021KM20061229043102.hdf":0 test_b0.tif

gdal_translate HDF4_SDS:UNKNOWN:"AMOD021KM20061229043102.hdf":1 test_b1.tif

You will need to update HDF4_SDS:UNKNOWN:"AMOD021KM20061229043102.hdf to reflect your own dataset, and you can retrieve this information using gdalinfo.

Also, the documentation on the GDAL website relating to the HDF format provides a lot of useful information and examples that should further assist you.