“…About the bandwidth of kernel density analysis, some similar studies usually use k-order nearest-neighbor analysis to delimitate the bandwidth for each city [84,85]; however, the number of sample cities in our study is much larger, and it will be very difficult to carry out the k-order nearest-neighbor analysis for the 286 sample cities once at a time. We think 500-meter bandwidth is a good choice from a practical point of view: first, the upper limit for walking is usually 800 meters of path distance [50,53], approximately 500 meters of Euclidean distance in a grid city. Second, according to the Standard for Residential Planning published by the Ministry of housing, service radius of basic amenities at neighborhood level, such as bus stops, kindergartens, community centers, and grocery shops is also 800 meters of path distance.…”