Using spatial data to identify food accessibility in large African cities

Current food security metrics are poorly suited to evaluate urban food security in Africa because they do not capture important spatial dimensions of food accessibility. The spatial dimensions of food accessibility are related to the interaction between changes in individual entitlements, or the ability to acquire food, and the availability of and accessibility to different forms of food-related infrastructure. The unavailability or periodicity of food security data, and high cost of collecting on-the-ground data, further complicates our ability to measure urban food security in rapidly growing urban areas. Leveraging and integrating spatial data on food retailer distribution, public transportation and road networks, population density, and access to electricity (nighttime lights) can provide sub-residential area scale insights into urban food accessibility and food environments − the areas where individuals acquire and consume food. We integrate a food access measure with a poverty index derived from remotely sensed data to empirically demonstrate spatial food access variability across food environments in Lusaka, Zambia. This novel spatial approach identifies areas of low food access and high poverty at a sub-residential area scale, highlighting areas that are most vulnerable to food insecurity. This method can be applied to other urban contexts to improve intervention targeting by policymakers and development practitioners. We demonstrate that highlighting the role of the spatial dimensions of food accessibility emphasizes the interaction between city planning and infrastructure, which contributes to the food environment, while also providing a means of understanding the spatial and systemic conditions that contribute to or hinder urban food security.