Using Local Knowledge to Better Map Food Deserts

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Across many urban and even rural regions, vast areas lack basic access to healthy, varied range of fresh fruits, vegetables, and meats. Convenience, processed foods and fast foods often exist and take the place of supermarkets, small grocery stores, or other outlets that might provide for a healthy, fresh food supply.

Mapping and understanding food deserts is important if we are to understand how best to tackle the lack of healthy food options in the United States. However, this is more than simply putting dots on a map of where food stores and consumers are. Integrating spatial data with subject-derived knowledge might be the key.

Food Insecurity and Food Deserts

One thing the Covid-19 pandemic has highlighted among underprivileged families in the United States is the scale of food insecurity. Before the pandemic, over 10% of all households in the United States were described as living as food insecure. That number likely doubled during the pandemic.

Food insecurity is the lack of access to fresh foods, where areas that lack this access have been described as ‘food deserts’. Food insecurity is particularly prevalent in regions where households are below the poverty line, where food insecurity rates are about 35%.

Why food insecurity persists in a rich country such as the United States is complex. Part of this could be market dynamics, where food suppliers may be less inclined to build retail outlets in poorer neighborhoods. But there are also historical reasons. Structural racism, segregation, redlining, that is historical legacies of not providing basic services to certain minority groups, and other long-term legacies have liked also played a role.

Mapping Where Americans Shop for Food

Mapping food insecurity often entails mapping the closest supermarket or major food retailer to households. However, most or many Americans shop in stores they prefer rather than simply shop at the nearest location. (Related: Urban Farming Increases Food Resources for Local Populations)

For instance, lower income households were found to shop near areas of work rather than their home.[1] During the pandemic in 2020, call data from 2-1-1, that is non-emergency calls for assistance, shows a wide disparity in calls related to food insecurity, with much higher and accelerated rates of food insecurity in poorer neighborhoods using zip code call data.[2] Even when stores were near households, access was often restricted for one reason or another.

Using GIS to Identify Food Deserts

In a recent research article, it was noted that a lot of geospatial researchers used food stores as fixed sites rather than as complex nodes that work in a distribution network, where these nodes also have complex relationships with shoppers. For instance, store preferences, relationships of retailers with people in given areas, and mobility patterns of shoppers all need to be accounted for to understand food deserts.

A small scale map showing  Low-Income, Low-Access Areas, 2019.
A small scale map showing: Low-Income, Low-Access Areas, 2019. Green shading maps out low-income census tracts where urban residents live more than 1 mile or where rural residents live more than 10 miles from a supermarket. Map, CRS using USDA’s Food Access Research Atlas.

In fact, some researchers have stated that other terms, such as ‘food apartheid or supermarket redlining’ might be better terms to describe complex relationships between neighborhoods and food stores that highlight food insecurity. What this points out is that a relationship-oriented analysis, that looks at how stores adapt and react to their shoppers, including how they may limit some shoppers, might be needed when applying spatial methods. This also includes understanding the behavior of food shoppers and households in greater detail.

Mapping endeavors may need to incorporate time and place in analysis, while undertaking a better understanding of food store and shopping behavior.[3] Furthermore, as the Brookings study points out, it is imperative to incorporate food outlets that include community gardens, small grocers, farmer markets, and more complex ways in which food is made accessible.

Participatory mapping, which empowers locals within neighborhoods, to be involved in providing spatial data on issues such as health and food insecurity could also allow for better data access. Individuals attempting to access food in their own households might be the best source of data for geographers studying food insecurity.

The Brookings research has highlighted how much of food insecurity is a problem related to a lack of financial resource access. However, to understand the problem in greater detail, and address needs as they arise such as during the pandemic, it will be important to empower locals to map and indicate areas of greatest needs.

For instance, in one study, using participatory GIS (PGIS), tobacco shops around parks were found to be a high source or atractors for neighborhood crime, something entirely missed by experts or others looking at crime. In other words, getting data directly from individuals reporting events, in this case crime, or lack of access to resources or how resources are obtained, in the case of food, could be a better way to obtain needed data for geographers interested in studying so-called food deserts.[4] A lot of previous research simply overlooked this fact and focused too much on only mapping where larger food stores were located and populations surrounding them.

Food deserts are a persistent problem in the United States, highlighted even more so during the pandemic. While we know historical legacies and continued poverty have exacerbated this problem in many regions, understanding how to alleviate it may require more nuanced analysis that does not simply rely on mapping available data but attempts to more greatly involve the subjects mapped and studied.

In particular, understanding the food web in neighborhoods, how people access food, and behavior of stores and food shoppers will be critical if we are better able to understand why food deserts develop and what policy interventions could work best in alleviating them. 


[1]    For more background into food deserts, underlying reason for them, and food shopping behavior in the United States, see:

[2]    For more on food insecurity during the pandemic and using 2-1-1 call data, see:  Janda, Kathryn, Raven Hood, Amy Price, Samantha Night, William Marty, Amanda Rohlich, Kacey Hanson, Marianna Espinoza, and Alexandra van den Berg. “Examining Food Insecurity and Areas with Unmet Food Needs during COVID-19: A Geospatial, Community-Specific Approach.” Journal of Agriculture, Food Systems, and Community Development, June 24, 2021, 1–13.

[3]    For more on food insecurity and mapping, including using a relational approach of food stores to consumers, see:  Shannon, Jerry, Ashantè M. Reese, Debarchana Ghosh, Michael J. Widener, and Daniel R. Block. “More Than Mapping: Improving Methods for Studying the Geographies of Food Access.” American Journal of Public Health 111, no. 8 (August 2021): 1418–22.

[4]    For more on participatory GIS and how it can be used to study issues of health or crime, see:  Douglas, Jason A., Andrew M. Subica, Laresha Franks, Gilbert Johnson, Carlos Leon, Sandra Villanueva, and Cheryl T. Grills. “Using Participatory Mapping to Diagnose Upstream Determinants of Health and Prescribe Downstream Policy-Based Interventions.” Preventing Chronic Disease 17 (November 5, 2020): 200123.


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