I have a Shapefile imported into a QGIS project as layer. And I have created a Style for that layer using a Column from the attribute table. To name it I have grouped several landuse-classes to a group (for example: crop, corn etc. would be grouped to arable-field) to give them a single color in the main window. The names for the landuse classes are in the column named "landUse" in the table.
What I want to do is export to a Raster file (ESRI ASCII Raster including a raster attribute table preferably) but using my grouped classes instead of the normal landUse field in the attribute table as cell info.
When I click on the "vector to raster" menu item in the "raster" menu I can only choose a column from the attribute table.
One of my ideas would be creating a column in the attribute table and giving it a value depending on the value in the column "landUse" and then use this column to rasterize. How do I do that and would that even work or are there other ways?
I am not experienced in GIS. I've tried if a few examples/tutorials similar to my problem to see if they could be applied, but yet nothing works.