I am attempting to add relief shading to map using .asc raster files, following this tutorial. It works well, but I have only tried it on single tile of raster data which is 20x20km. I want to generate the shading for a much larger area, which means multiple tiles.
I understand I can input GDAL commands in the Hillshade/DEM dialogue in QGIS, and the tutorial suggests this means I can perform a batch operation, but I don't know enough (read any) GDAL to do this.
I am using QGIS 1.9 on Ubuntu (though I do have a Windows installation as well).
EDIT: I have written the following script, demraster.sh:
!/bin/sh for f in *.asc do echo "Processing %f" gdaldem hillshade %f -z 1.0 -s 1.0 -az 315.0 -alt 45.0 done
I have set it to be executable with chmod, and run it with sh demraster.sh but get a syntax error:
Syntax error: word unexpected (expecting "do")