Oxfam's Food Price Pressure Points Map. Through a comment on that post made by Amy Young-Buckler I learned about two related maps that might be of interest to you.
The USDA's Food Desert Locator is a map of food deserts in the United States. The map shows the counties in the US in which a substantial number of people in that area have low access to a large grocery store or supermarket. Click here to read the USDA's definitions of low access and low income areas. You can click on the placemarks on the Food Desert Locator to open information about that food desert.
The USDA's Food Environment Atlas is an interactive map that you can use to visualize many different data sets related to food prices, food access, health statistics, and socio-economic characteristics related to food in the United States. Select one or more data sets from the menus to create a map.
Applications for Education
Both the Food Environment Atlas and the Food Desert Locator could be used in a similar manner to the Oxfam map for creating lessons on nutrition, environment, geography, and agriculture. Have students investigate the causes of food deserts then develop and propose their own solutions to the causes.