I have acquired LoD2 building models in the 3DShape format (Polygon ZM). This LoD2 data needs to be prepared for a R-script of solar irradiation calculations on roof surfaces, but which can only process raster data.
Is there a way to 'rasterize' the 3D Shapefile into a digital surface model (DSM)?
Lets say for example, that I want a spatial resolution of 0.25 x 0.25 meters for each raster cell, than the height of the highest feature (i.e. the roof polygon) should be extracted from the LoD2 data at the location where it intersects with the center of each raster cell. So that in the end I get a 'DSM' of the shapefile.
Sample LoD2 data can be downloaded here: http://vermessung.bayern.de/file/zip/6817/LoD2_3DShape.zip
I have found nothing in the ArcGIS help resource center, and no GRASS function either. ArcGIS, QGIS, GRASS and R are available to me.
If you know a alternative way to calculate solar irradiation on a 3DShape surface, you would be of help as well. I have irradiation measurements for an fixed normal (=horizontal) surface in the area. What my R script does is it calculates the effect of the rooftop geometry and the shadows of nearby objects (= other buildings) on the measured irradiation at 1 hour time-steps over an entire year and then summarizes the W/m² to evaluate which rooftops get the most sunlight.
Answer
Found a solution using ArcGIS:
I use the tool
3D Analyst >> Data Management >> TIN >> 'create TIN'
to create a TIN file with the setting 'SF Type: hardclip'.
Then I use the tool
3D Analyst >> Conversion >> From TIN >> 'TIN to Raster'
to create the raster DEM. Because of the size of the buildings that I want to identify (singe residential houses), I used 'CELLSIZE 0.25' to create smooth edges.
I guess the same can be done with GRASS, which is what I'll try next.
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