I'm having some really nice raster maps in geotiff format. I would like to add some features to these maps as well as then exporting them as tiles for serving the map from a web server.
Preferably I would want to be able to work with the different geotiff files in a software like QGis or similar. As I want to add some vector components and combine the different TIFF files before I export them to one big geotiff with all features needed.
Though my biggest problem is that in QGis I can't export geotiffs with higher resolutions than the current screen resolution, which makes it rather pointless as I'm working on a quite big map.
So I'm wondering what possible ways there are to do what I have just described. Can I combine QGis with any other tools or how would you do it?