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.

基于高斯的两步浮动服务区法（Gaussian-based Two-Step Floating Catchment Area, G2SFCA）是一种精密的空间可达性测度方法，其通过引入高斯距离衰减函数，对基础两步浮动服务区法（Two-Step Floating Catchment Area, 2SFCA）进行了拓展。该方法能够更真实地刻画医疗等公共服务的可达性随距离增加而衰减的客观规律。G2SFCA包含两个核心步骤：其一，针对每个服务点位计算供需比，以高斯函数为权重分配工具，对距离服务点更近的人群赋予更高权重，对距离较远的人群则逐步降低权重；其二，在每个人口点位上，汇总该服务区范围内所有服务点位经高斯函数加权后的供需比之和。通过应用高斯衰减函数，G2SFCA能够实现更精准且连续的空间可达性评估，反映出服务影响力随距离增加而逐渐衰减的客观特性。