This past November, we released the report Getting Groceries: Food Access Across Groups, Neighborhoods, and Time. Expanding on this report, we created an interactive map to display food access information for each block group in Marion County. Click on a block group to view the closest grocery store or supermarket by car, bus, and foot, and the time it would take to get to the grocery using each travel mode. Block groups are boundaries defined every 10 years by local partners and the U.S. Census Bureau. They typically contain a few hundred households.
The color of each block group is based on the time it takes to walk to the nearest grocery. In dark purple neighborhoods, a grocery is a five minute walk away. In light purple neighborhoods, it takes 30 minutes or more to walk to the grocery.
For this blog, three different datasets were used.
- SAVI Grocery Stores and Supermarkets: This data is curated from the Marion County Health Department food inspection reports.
- Marion County street centerlines: This data comes from the OpenIndy Data Portal.
- Bus routes and stops: This data comes from the OpenIndy Data Portal.
This analysis was done by finding the centroid for each block group. These centroids were then used as starting points for each travel mode. The centroid is the geographic center of a block group.
Walking: Walking time was calculated using a walking speed of 2.8 miles per hour, the same speed used by Google Maps.
Driving: Driving times were calculated with ArcGIS Online, using data provided by HERE. Traffic estimates were based on Monday at 6 p.m.
Bus: Bus routes were calculated by using a ¼ mile network distance around block group centroids. The stops that were within a quarter mile of the block group center were used as origin points to grocery stores. Bus times were calculated using the IndyGo basic service standard speed of 14 miles per hour.