# GIS-Based Evaluation Method for Accessibility of Social Infrastructure Facilities
## 1 Introduction  
Social infrastructure is defined as a complex system of facilities, programs, and social networks that aim to improve the quality of life [1]. It includes educational, medical, cultural, and sports facilities that are essential for the everyday life of citizens. Central and local governments have developed a social infrastructure plan to ensure the following: (1) the areas are sufficiently supplied with social infrastructure; (2) social infrastructure is as equitably distributed as possible; (3) social infrastructure is effectively and efficiently configured so that service providers can flexibly respond to changing local community needs over a long time period [2]. New towns or cities built through systematic planning are generally considered to have an adequate level of social infrastructure facilities. However, old towns or cities do not have an adequate level of social infrastructure. Local governments that administer old towns are interested in improving social infrastructure. Accordingly, financial investment is increasing in these regions. The scope and definition of a social infrastructure varies depending on the characteristics and circumstances of a country. In Melbourne, Australia, swimming pools, recreation centers, community conference spaces, nurseries, libraries, senior welfare facilities, disabled welfare facilities, parks, hospitals, elementary schools, and middle schools are defined as social infrastructure [3]. In Germany, public services include education, welfare, health care, community, electricity, and water and sewage, which are basic services in everydaylife of the people [4]. London, UK, social infrastructure includes health and social care, education, childcare center, recreation facilities, public toilets, and burial space [5]. Facilities and services necessary for a city are classified into culture, welfare, childcare, education, health care, commerce, and finance, which include facilities and services such as childcare centers, kindergartens, schools, hospitals, markets, welfare centers, post offices, and banks in Japan [6]. There have been two approaches to social infrastructure planning in cities. The first is a population-based approach, and the other is an access-based approach. An example of a population-based approach is presented in Healthy Urban Planning. Basic social infrastructure is needed within 1 km of the home for the community of 4000 to 5000 people [7]. Similarly, the only criterion for providing social infrastructure in South Korea was the population or number of households in the region. However, if only the population is considered in social infrastructure planning, the convenience of the residents might be overlooked. For example, a study found that the average distance from old-age, low-rise housing to social infrastructure in some areas in South Korea was approximately 2.7 km [8]. The elderly cannot walk 2.7 km to use the facilities. Therefore, these social infrastructure facilities do not effectively increase the convenience or quality of life of residents. In order to resolve this problem, the Korea Ministry of Land, Infrastructure, and Transport (KMoLIT) put forward access-based guidelines in 2018 for social infrastructure planning. The new guidelines use travel time to a facility (on foot or by vehicle) as the threshold for determining the satisfaction in terms of residents' convenience [9]. For example, the Korean government is planning to build a park so that anyone can use the park within 15 min of walking from home. This threshold seems reasonable because although sufficient social infrastructure facilities are provided in a region, they do not enhance residents' satisfaction and quality of life if they are located in a poorly accessible location. However, any explicit method of evaluating the accessibility of social infrastructure facilities has not been proposed.