Working with QGIS and Grass I would like to produce a ZTV. I have the bare land DEM happily ready to go but would like to add buildings and woodland to the calculation. Can anyone please point me in the direction of how to add buildings and woodland to the DEM upon which I will be doing the ZTV?
The way I have done this in the past is to convert buildings, forested areas, etc. to a raster (rasterize the polygon using the height column for the raster value, using the same pixel resolution as the DEM). Then merge the two rasters (DEM and rasterized buildings). This will add the building height to the DEM. One thing to note is that you will probably want to have the areas under buildings flat prior to adding the building features, otherwise you may have buildings with different slopes for roofs.