I want to make a visibility analysis of planned wind turbines in my region.
I have a DEM raster and a polygon describing the possible area where the wind turbines might be set up.
People are complaining, that the view to a prominent mountain in the region will be disturbed.
My "simple" plan is, to raise the DEM-values covered by the polygon up to 200 meters and then perform a visibility analysis from the top of that mountain to be able to identify the regions, where the wind turbines might "block" the view.
Problem: I'm not able to successfully combine the vector and the DEM.
Steps taken so far:
- Polygon was clipped from the DEM
- Raster values from the clipped part were set to 200
What doesn't work:
When using the raster calculator, trying to add DEM + clip, the resulting image only covers the clip.
As i understand, the extend of the two rasters should be the same, and that NoData values will prevent operations (googling for 3 hours without success).
I fail in resizing my clip to the DEM and also do not get rid of the NoData values.(Really tried every tool under Raster to no avail)
Unfortunately, the rastercalc tutorials i found do not cover these "basic" things, so i'm completely lost at the moment.
p.s. using latest qgis master from osgeo4w