WASP roughness length map

Question

I come across WASP python example (please see the link below).

https://gitlab.windenergy.dtu.dk/WAsP/pywasp-examples/-/blob/master/tutorial_1/pywasp_tutorial_resource_grid.ipynb

The example mention about roughness map. It says that

"a map of roughness lengths was created based on the CORINE 2018 landcover dataset, using a "looddkup table" which assigns particular lengths to each landcover type."

Does anyone know how the roughness map was created? I think they use windkit to produce the map. But I am not too sure.

i have searched online. but could not find the answer. I think they downloaded corine 2018 land use data and use wasp roughness lookup data corresponding to land use type. but I could not find the look up table. I think the table should be in windkit.

Answer 1

Windkit does ship with a number of lookup tables for common landuse datasets, but we don't do a great job of exposing them. They are stored in the windkit/landcovertables directory. The different landcover datasets available are listed in the windkit.get_map documentation

You can read the CORINE lookup table into memory like:

import windkit as wk
wk.landcover.LandCoverTable.read_json(pathlib.Path(wk.__file__).parent / "landcovertables"/ "CORINE.json")

If you have a rastermap of the landcover data, you can then write it out as a roughness map using the windkit.raster_map.raster_map_to_file function. You would want to set the lctable_var argument to "z0".