ABSTRACT
Chapter 5 focuses on various GIS-based measures of spatial accessibility. Accessibility refers to the relative ease by which the locations of activities, such as work, school, shopping, recreation, and healthcare, can be reached from a given location. Disadvantaged population groups (e.g., low-income and minority residents) often suffer from poorer accessibility, and the disparity calls for planning and public policy to mitigate the problem. The chapter begins with an overview of issues on accessibility, followed by GIS-based methods for defining spatial accessibility: the popular two-step floating catchment area (2SFCA) method and the generalized 2SFCA (G2SFCA) method. Two new methods are then introduced: the inverted 2SFCA (i2SFCA) method estimates potential crowdedness in facilities, and the two-step virtual catchment area (2SVCA) method measures virtual accessibility (accessibility via internet), for example, telehealth. The methods are first illustrated step-by-step in a case study of various accessibility measures for primary care physicians in Baton Rouge. An automated toolkit is then introduced for implementing these methods.
