This function attemps to allocate cities to relevant PRA IDs.
get_PRA_result_name_1999(result, pra)
Should probably rely on PRA_xw()
instead here.
Auvergne Alpes Rhones map: https://draaf.auvergne-rhone-alpes.agriculture.gouv.fr/IMG/pdf/no9_Analyses_VVT_2015_enligne_cle87d384.pdf