The Spatio-temporal Disparities in Healthy Food Accessibility: A Case Study of Shanghai, China

The supply of healthy food is distributed unequally in city. The accessibility of healthy foods is affected by both locations and traffic conditions. This paper examines spatio-temporal disparities in healthy food accessibility in Shanghai communities. Firstly, we choose all communities in Shanghai and use python as a crawling tool to collect healthy food store POI (e.g. agricultural markets, vegetable markets, fruit markets, aquatic seafood markets, supermarkets and comprehensive markets) from Gaode Map and get 23,436 points to calculate the amount and density of healthy food store in various communities. Secondly, after comparing Baidu Map and Gaode Map, leading platforms of Web GIS services in China, we choose Baidu Map to collect data to study the spatio-temporal difference in accessibility by using network analysis and developing a crawling tool to collect different travel time (e.g. walking and public transportation) for each community to the closest healthy food store at each time of day (0:00-24:00). Thirdly, we set up a variable to see at what time are people in the communities able to reach their nearest healthy food store in 15 minutes and the ratio of the above-mentioned time to the whole day is calculated so that we can evaluate the temporal disparities of healthy food accessibility. Additionally, we use global and local spatial autocorrelation to analyze the spatial patterns of the temporal disparities of healthy food accessibility, based on the Moran’s index and the local indicator spatial association (LISA) index. Finally, on the basis of the research above, the food desert map is drawn. The results of this analysis identify the communities in Shanghai with the greatest need for improved access to healthy food stores and the variance of accessibility affected by the traffic in different times will be taken into account. Ultimately, this study explores a more complete and realistic condition of healthy food accessibility in Shanghai and the corresponding improvement strategy is proposed.