balancing_cost          Balancing cost accessibility measure
concentration_index     Concentration Index
cost_to_closest         Minimum travel cost to closest N number of
                        opportunities
cumulative_cutoff       Cumulative access based on a travel cost cutoff
cumulative_interval     Cumulative access based on maximum travel time
                        interval
decay_binary            Binary (a.k.a. step) decay function
decay_exponential       Negative exponential decay function
decay_linear            Linear decay function
decay_logistic          Logistic decay function
decay_power             Inverse power decay function
decay_stepped           Stepped decay function
fgt_poverty             Foster-Greer-Thorbecke (FGT) poverty measures
floating_catchment_area
                        Floating catchment area accessibility
gini_index              Gini Index
gravity                 Gravity-based accessibility measures
palma_ratio             Palma Ratio
spatial_availability    Spatial availability
theil_t                 Theil T Index
