G2SFCA (Gaussian-based Two-Step Floating Catchment Area)

The Gaussian-based Two-Step Floating Catchment Area (G2SFCA) method is a sophisticated spatial accessibility measure that extends the basic Two-Step Floating Catchment Area (2SFCA) approach by incorporating a Gaussian distance decay function. This method provides a more realistic representation of how accessibility to services, such as healthcare, diminishes with distance. The G2SFCA involves two key steps: firstly, it calculates a supply-to-demand ratio at each service location, using a Gaussian function to apply greater weights to populations closer to the service and progressively smaller weights to those farther away. Secondly, it aggregates these ratios at each population location by summing the Gaussian-weighted supply-to-demand ratios from all service locations within the catchment area. By applying the Gaussian decay function, G2SFCA offers a more accurate and continuous assessment of spatial accessibility, reflecting the gradual decrease in service influence over distance.