I have a single-band geotiff DEM and I have managed to create a color version of it (with single-band pesudocolor) and a hillshade (with Terrain Analysis --> Hillshade). As per the online lesson (https://docs.qgis.org/2.2/en/docs/training_manual/rasters/terrain_analysis.html), I can overlap the hillshade over the color map and it looks great. My only problem is I want to export it out of QGIS as a single unified GeoTIFF for use in other softwares.
This (http://dirkraffel.com/2011/07/05/best-way-to-merge-color-relief-with-shaded-relief-map/) suggests using ColorMagick's convert, but this results in very large files and often crashes for me, not to mention the coordinate data gets lost.
This (https://anitagraser.com/2012/01/19/a-guide-to-beautiful-reliefs-in-qgis/) is another option, but I find it very hard to put fitting color scales and the hillshading cannot be controlled.
This (http://blog.mastermaps.com/2012/07/terrain-mapping-with-mapnik.html) relies on Mapnik, which is currently not an option for me.
Can anyone suggest an efficient solution which allows to blend two (large) overlapping geotiffs with the top one (hillshade) being slightly transparent?
For anyone interested, I cobbled together this GDAL script from the first source, which gets the job half-done:
set input_dem=test-mbes2.tif set input_hill=test-illumination.tif convert -gamma .5 %input_hill% hills_gamma.tif convert %input_dem% hills_gamma.tif -compose Overlay -composite output.tif listgeo %input_dem% > meta.txt geotifcp -g meta.txt output.tif final.tif