## 2 Materials and Methods
### The Construction Process of ASFC-RA  
We will introduce the construction process of ASFC-RA, which consists of steps II, III, and IV in Figure 2. The premise of diversification is a feature of a reasonable and comprehensive classification system of service facilities; thus, the calculation travel time costs based on route planning API from Internet map data is a convenient spatial standard for determining whether the service facilities are accessible or not. In the following sections, we outline the design philosophy of a modified cumulative opportunity measure model through various types of service facilities. (1) The category system of service facilities  
Firstly, it is necessary to construct a service facilities classification system in the residential areas. The classification system of service facilities in residential areas will be built based on the four concepts of basic human living requirements proposed by the World Health Organization. First, the system should be selected according to the principle of ensuring living conditions, and this information then needs to be combined with the living environment of the city [31]. This paper refers to a total of 339 indicators in the evaluation index systems of nine livable cities at home and abroad; these indicators comprehensively consider the attributes of residential life services in residential areas from six aspects, including life services, education services, leisure services, transportation services, medical services, and employment services. The detail category information is as shown in Table 2.  
The identified methods of travel include walking, public transportation, self-driving, cycling, and combinations of these methods [22]. Many factors influence the choice of travel mode, including economic conditions, travel distance, and travel urgency. Walking is the most basic and most common mode of travel for human beings [32]. The principle that is usually followed is as follows: people will choose to walk if a destination can be easily reached by walking. Therefore, to quantitatively judge the service radius of service facilities, the walking mode is used for measurement purposes. To determine the passing time of the travel time costs threshold, the time cost of five types of service  
Figure 2: Overall assessment roadmap. facilities, including life, education, leisure, travel, and medicine, was determined to be 30 minutes. It is believed that employment causes a specific type of commute between work and home, and this commuting distance can be significant and differs from that of other trips; thus, the time was selected as 60 minutes. 2. Gaining accessible service facilities of the ASFC-RA  
This paper uses Python3.6 and ArcGIS ArcPy (10.2, Esri, Redlands, California, America) to write a parsing program for layer data parsing to gain the accessible residential service facilities through route planning API from Amap. The code has been uploaded to GitHub, and the address is [[https://github.com/windofmay5/PublicFacilitiesNavigation](https://github.com/windofmay5/PublicFacilitiesNavigation)]([https://github.com/windofmay5/PublicFacilitiesNavigation](https://github.com/windofmay5/PublicFacilitiesNavigation)). The specific steps are as follows: