def gcam_to_demeter_lc_map(setting='standard'):
    """Mapping from GCAM land classes to Demeter land classes.

    :param setting:                 Describes the mapping dictionary needed. Options are "standard" or "crop_yield"

    """

    standard = {'biomass': 'crops',
                  'Corn': 'crops',
                  'FiberCrop': 'crops',
                  'FodderGrass': 'crops',
                  'FodderHerb': 'crops',
                  'Forest': 'forest',
                  'ProtectedUnmanagedForest': 'forest',
                  'Grassland': 'grass',
                  'ProtectedGrassland': 'grass',
                  'MiscCrop': 'crops',
                  'OilCrop': 'crops',
                  'OtherArableLand': 'crops',
                  'OtherGrain': 'crops',
                  'PalmFruit': 'crops',
                  'Pasture': 'grass',
                  'ProtectedUnmanagedPasture': 'grass',
                  'Rice': 'crops',
                  'Root_Tuber': 'crops',
                  'Shrubland': 'shrub',
                  'ProtectedShrubland': 'shrub',
                  'Tundra': 'grass',
                  'RockIceDesert': 'sparse',
                  'SugarCrop': 'crops',
                  'UnmanagedForest': 'forest',
                  'UnmanagedPasture': 'grass',
                  'UrbanLand': 'urban',
                  'Wheat': 'crops'}

    crop_yield = {'Wheat_IRR': 'wheat_irr',
                     'RootTuber_IRR': 'root_tuber_irr',
                     'SugarCrop_IRR': 'sugarcrop_irr',
                     'OilCrop_IRR': 'oilcrop_irr',
                     'MiscCrop_IRR': 'misccrop_irr',
                     'FodderHerb_IRR': 'fodderherb_irr',
                     'Corn_IRR': 'corn_irr',
                     'FiberCrop_IRR': 'fibercrop_irr',
                     'FodderGrass_IRR': 'foddergrass_irr',
                     'Rice_IRR': 'rice_irr',
                     'OtherGrain_IRR': 'othergrain_irr',
                     'Wheat_RFD': 'wheat_rfd',
                     'RootTuber_RFD': 'root_tuber_rfd',
                     'SugarCrop_RFD': 'sugarcrop_rfd',
                     'OilCrop_RFD': 'oilcrop_rfd',
                     'MiscCrop_RFD': 'misccrop_rfd',
                     'FodderHerb_RFD': 'fodderherb_rfd',
                     'Corn_RFD': 'corn_rfd',
                     'FiberCrop_RFD': 'fibercrop_rfd',
                     'FodderGrass_RFD': 'foddergrass_rfd',
                     'Rice_RFD': 'rice_rfd',
                     'OtherGrain_RFD': 'othergrain_rfd',
                     'Forest': 'forest',
                     'Grassland': 'grass',
                     'OtherArableLand': 'otherarableland',
                     'PalmFruit_IRR': 'palmfruit_irr',
                     'PalmFruit_RFD': 'palmfruit_rfd',
                     'Pasture': 'grass',
                     'RockIceDesert': 'snow',
                     'Shrubland': 'shrub',
                     'UnmanagedForest': 'forest',
                     'UnmanagedPasture': 'grass',
                     'UrbanLand': 'urban',
                     'biomassGrass_IRR': 'biomass_grass_irr',
                     'biomassGrass_RFD': 'biomass_grass_rfd',
                     'biomassTree_IRR': 'biomass_tree_irr',
                     'biomassTree_RFD': 'biomass_tree_rfd',
                     'Tundra': 'sparse'}

    if setting == 'crop_yield':
        return crop_yield
    else:
        return standard