Solweig - save output in float32

[bartpannemans]

Issue: In Solweig all output is now saved as float 64. For many variables this doesn't seem to make much sense: Tmrt, Kup, Kdown, Lup, Ldown. Using float32 would be probably OK for these variables. An advantage is that outputfiles of float32 are only half the size of float64 files (resulting in faster I/O, less storage).

Proposed solution: An obvious place to do this conversion seems to be in ./umep/functions/SOLWEIGpython/solweig_runner.py -> class SolweigRun -> method run(). Toward the end of this method (line 630 and further), the function common.save_raster() is called a couple of times to write the raster Tmrt, Tmrt_avg, , ... This could be replaced by Tmrt.astype(np.float32).

Remarks:

• maybe downstream umep modules require these file to be in float64.
• maybe it would be even more efficient to move the dtype-conversion earlier in the processing, so that other parts of the code also profit.

[biglimp]

Thank you for this. We should consider this improvement.

[songololo]

Agree that this should work. FYI the experimental rust version uses f32 for rust specific code already.

[bartpannemans]

Additionally you may consider similar improvements in:

• ./umep/wall_heightaspect_algorithm.py -> generate_wall_hts -> saving of wall_hts.tif and wall_aspects.tif
• ./umep/skyviewfactor_algorithm.py -> generate_svf -> saving of 16 tif files like svf.tif, svfW.tif, svfEaveg, ... svf_total.tif
  For the latter function, several teams are already working on GPU-accelerated versions, where the output may get tweaked in a similar way.
  I have made such changes in my local code. Let me know if you'ld like me to upload them in a PR, but the changes are relatively straightforward, I would say.

[songololo]

Pull Request submitted #23