The rpv libraries are collections of spectral BRDFs of different surface types, This option must be used either with surface_type or surface_type_map, in order to select the specific surface type.
For using a rpv_library write
rpv_library library_path
where library_path is the path of the directory, where the BRDF data is stored. The files are
expected to have the names IGBP.01.rpv, IGBP.02.rpv, ... If surface_type 1 is specified
the BRDF from IGBP.01.rpv will be used, and so on.
Each file must have the structure like an rpv_file.
(This option is quite the same as rpv_file, except that it offers you an
easy way to use the option surface_type_map in combinition with your rpv_files.)
rpv_library IGBP
The built-in library contains the first 17 surface types see
albedo_library. The data is given for the wavelengths 443nm,
565nm, 670nm, and 865nm. Stay near this wavelength in order to get
reasonable results. In future this the rpv-library will be NDVI
dependent, but until now the most common NDVI class is selected
automatically.