Sunday, March 1, 2015

LA Food Deserts

Desktop version
iPad version
(I do not recommend viewing the visual on mobile)
  • Click on a zipcode.
    • The selected zipcode remains and other zipcodes should be grayed out.
    • Hovering over a polygon will give you the zipcode, city name, and median income for the area.
  • The "Grocer Yelp Ratings", "Access Points", and "Adjusted Gross Income" information should update with data for the selected zipcode.
  • To use the filter box, type in the zipcode and press "Enter". All zipcodes should disappear and the matching zipcode will remain (if any). No information will update until that zipcode is clicked on.
  • Multiple zipcodes can be selected also.

When I worked in South LA, it seemed like there were no grocery stores nearby. Sure, there were plenty of fast food places around for burgers and fries. But when I wanted buy groceries to leave at my desk for the work week, it seemed like I had look far and wide. Why was it so hard to find a grocery store for food but a McDonald's was right around the corner? I was beginning to believe I worked in the middle of a food desert.

A food desert is a geographic area where residents lack access to healthy food options. And lack of access could mean many things: distance, convenience, or low-income. All these things could potentially affect a resident's ability to acquire healthy food options.

I looked on USDA's Food Access Research Atlas to see if I lived, according to the US government, in a food desert. To my surprise, the area where I worked was not a food desert! A grocer may have been within a mile away but it felt so inconvenient when all these other food options were so common. There was a casual bakery/cafe place known for having healthy sandwiches but they are pretty pricey. It would add up to a serious expense if I ate there on a daily basis! So I was experiencing a lack of access and I didn't even live in the area! I just worked there!

Map Features

This inspired me to make the visualization you see here. I'm proud to provide a visualization of food deserts that captures more of the factors that define the issue. Lack of access is a multi-faceted problem; it's more than just the distance to a grocery store. Poverty and income come to play. Do the grocery stores provide an economically viable means of food to residents? The USDA used a population-weighted centroid to compare distances of census tracts to grocery stores. I was able to find a dataset for Los Angeles that provided all residential zones. So distances are calculated from the residences themselves!

The density of grocery stores vs. other food options are important. Especially in urban areas where distances are much shorter than rural areas, fast food places could be an easy choice just by sheer abundance. McDonald's is only used as a metric to quantify convenience. McDonald's is not the cause of food deserts. It makes a great metric because they are affordable and very commonplace.

The Yelp ratings should also help identify if it's an affordable option to grocers. What would make sense is seeing more upscale grocers near higher income areas. If there were upscale grocers closer to poor areas, it would be unlikely that the residents can afford it. And if they can't afford it, they are more likely to get their food elsewhere.

The income distribution is to give a viewer a better summary of the social-economics of the area.

With the Yelp Grocer Ratings and socioeconomic distribution included in the data set, I hope to provide a higher fidelity to the food desert issue in Los Angeles in addition to the distances and abundance of grocers.

Why are you picking on McDonald's?
McDonald's is constantly under the public lens when the topic is public health and nutrition. McDonald's is included not because it is the cause of food deserts but because it is such a great metric. I believe that convenience and cheap will always win and McDonald's embodies both. It's distribution in a zipcode can be a great sample of the access a citizen has to fast food. After all, McDonald's isn't the only fast food option available. There are many others. So to represent the alternative choice a citizen would have as opposed to grocery stores, I chose McDonald's.

But if you believe convenience and cheap will always win, what chance does grocery stores and healthy eating have?

This is where I believe education plays a strong role. Knowledge of the effects of consuming too much fast food to often. Education and knowledge would be a great addition to this dataset since I try to capture all facets of the problem. However it would be very hard to identify something to quantify education...(email if you think of something!)

photo credit: Karen Chu


Distance to a grocer is not a good indicator of poor access. By examining a zipcode like Malibu 90265, you can see that the median distance to a grocer is ~2.5 miles. And 50% of residents drive further than that! However, the medium income for the area is $200,000 or more! Those with more disposable incomes can afford the longer trip. So food deserts should be identified with more than one metric. At the very least, it should be based on income and distance to a grocery store. So let's examine, zipcode 90810, an area within Long Beach. It is identified as a low-income and low-access area. There are 3 grocers and if the median distance is a mile, 2 grocers are within a mile! All the while, there are 2 McDonalds' that are within half a mile! Looking at the Yelp rating, there only one rating and it's two dollar signs ('$$')! Surely, a low-income area would benefit from a grocer that is considered a little more affordable (one dollar sign '$').

The Long Beach zipcode 90810 can be seen to have both ends of the income spectrum. There are people throughout the entire income ranges. This isn't particularly the norm. It's possible, like in zipcode 90059, to have nobody earning over $200,000 in the area. So in a diverse area such as Long Beach, there are high-income and low-income neighborhoods. If there were further investigations, what kind of neighborhood is close to the grocer? The high-income or the low-income neighborhood? What would it mean if the grocer serves one type of neighborhood instead of another? So it seems that even within a zipcode with grocery stores, access can still be poor for certain neighborhoods.

A low-income or low-access area follows the definition provided by the USDA:

1. They qualify as "low-income communities", based on having: a) a poverty rate of 20 percent or greater, OR b) a median family income at or below 80 percent of the area median family income;
2. They qualify as "low-access communities", based on the determination that at least 500 persons and/or at least 33% of the census tract's population live more than one mile from a supermarket or large grocery store (10 miles, in the case of non-metropolitan census tracts).

I hope that this provides a higher fidelity to the issue but I don't claim this will solve it. It should be used as a tool to identify the areas and then those who can investigate at the ground level, politicians and health advocates, can determine what solutions would best apply to that case.


My dataset can be useful to politicians resolving the issue of food deserts. Los Angeles dictates incentives for grocers to open their doors in South LA [link]. This visualization can help them determine more specifically more regions that greatly benefit from having a local grocer. The grocery stores themselves can determine whether their branch is best suited price-wise to open in a region. Public health advocates can use it to identify locations that will greatly benefit from educational actions for health awareness.

Update Awesome video about "South Los Angeles" and Food Deserts.
Tools and Data

Data sources


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