Skip to main content
Viable Food Systems Illinois Grocery Access

Data, software, and attribution

Data sources and third-party notices

This page identifies the principal public data sources, software libraries, map services, and limitations used by the Illinois Grocery Access tool.

Map attribution

Map data may include OpenStreetMap data. OpenStreetMap data is available under the Open Data Commons Open Database License (ODbL).

Map data © OpenStreetMap contributors

Principal sources and services

Links below point to the source or project home page. Source availability, terms, and contents can change over time.

USDA SNAP retailer data

The desktop updater downloads Illinois records from the USDA SNAP authorized-retailer source. The map update retains the download date and source metadata. SNAP authorization alone does not determine whether a store is classified as qualifying grocery access; the project classification rules and review decisions also apply.

USDA SNAP retailer data

Illinois WIC vendor data

The desktop updater uses Illinois WIC's operational public store locator by default. A checked agency-supplied CSV can replace that downloaded copy. The map update records which source was used and when it was downloaded or imported.

Illinois WIC vendor data

U.S. Census Bureau geography and geocoder

Census geography supports urban/rural classification, ZIP and place lookup, tract or block-group context, population fields, and address matching. Street-address requests use the Census geocoder; the public application reports when a match is approximate, ambiguous, unavailable, or outside Illinois.

U.S. Census Bureau geography and geocoder · Census geocoder

USDA Food Access Research Atlas

USDA food-access indicators support the low-income/low-access context shown by the application. These indicators are an analytical dataset, not a guarantee of current store conditions or an individual eligibility determination.

USDA Food Access Research Atlas

Community food pantries from OpenStreetMap

The optional pantry layer lists food pantries, food banks, and soup kitchens tagged in OpenStreetMap, which is maintained by volunteers under the Open Database License. Coverage is incomplete and hours, services, and eligibility rules are not verified by this project. Confirm the location, services, and hours before visiting.

Community food pantries from OpenStreetMap

USDA Local Food Portal

The optional farms layer lists farmers markets, farm stands, CSAs, on-farm markets, and food hubs published by the USDA Agricultural Marketing Service Local Food Portal. Listings are self-reported by operators and are often seasonal, so hours and open dates should be confirmed. These outlets are shown as supplemental local-food context and are not counted as full grocery access.

USDA Local Food Portal

CDC PLACES and community health context

When included in the published map data, CDC PLACES or related public health context is presented as an optional community overlay. It is population-level context and should not be interpreted as a diagnosis or an individual health record.

CDC PLACES and community health context

OpenStreetMap and Geofabrik extracts

OpenStreetMap-derived road and place data, distributed through an extract provider such as Geofabrik, support local routing preparation and selected store-hours matching. Extract dates and transformation details are recorded in the published map data.

OpenStreetMap and Geofabrik extracts · Geofabrik extracts

OpenFreeMap and OpenMapTiles

The public map uses a MapLibre-compatible basemap style and may request tiles from OpenFreeMap. OpenMapTiles and its data ecosystem are identified here because style and tile metadata can incorporate OpenMapTiles conventions. Tile availability and terms are controlled by the provider, not by MapLibre.

OpenFreeMap and OpenMapTiles · OpenMapTiles

MapLibre GL JS

MapLibre GL JS is the open-source browser mapping library that draws the map. It is software, not a source of geographic data or a routing service.

MapLibre GL JS

GraphHopper

The Windows updater may use a locally installed GraphHopper preparation service to generate driving and walking coverage. The public site reads the prepared coverage from the published map data; it is not a promise that every public request invokes a hosted GraphHopper API.

GraphHopper

External Google Maps links

Store records may include a link to a Google Maps search or store page for additional verification. The application does not embed Google photographs, does not claim Google endorsement, and does not treat an external listing as conclusive proof that a store is open or accessible.

External Google Maps links

How data is prepared

  • The Windows updater downloads and records source files, normalizes and deduplicates retailer records, verifies or annotates store hours where available, and records warnings for uncertain data.
  • Local routing preparation generates coverage for the configured urban and rural access standards and clips it to the applicable audience areas.
  • The desktop updater assembles the prepared files and source records into one server-ready update. The web application verifies and publishes the update, then uses those files for the map and assessments.
  • Administrative store reviews can change a store's classification or hours after publication. Those decisions are separate from the source data and are documented as review decisions.

Important limitations

  • Retailer lists, hours, addresses, authorizations, and external listings can be incomplete, delayed, duplicated, or wrong. A missing hour is not proof that a store is closed.
  • Straight-line proximity, routed coverage, census geography, and community indicators answer different questions. A coverage surface is not a promise about sidewalk quality, road safety, transportation availability, inventory, affordability, or a person’s eligibility.
  • Census, USDA, CDC, and Illinois WIC data are used for planning context. They are not individualized legal, medical, nutrition, benefits, or eligibility advice.
  • Basemap tiles and external links are third-party services. Their availability, terms, and content may change independently of this application.
  • The optional food pantry and farm layers are supplemental context, not grocery access. Community-maintained and self-reported listings are incomplete and their hours, services, and eligibility rules are unverified, so confirm before visiting.
  • Coverage is based on stores published in this state's SNAP and WIC sources and does not systematically credit stores across state borders. Access may therefore be understated near the state line.

Licensing and notices

Open-source software and public-data terms remain with their respective authors and providers. The deployed release preserves the required attribution and any applicable Open Data Commons Open Database License (ODbL) or extract-provider obligations. See the project third-party notice file for the release checklist.

Technical details
  • Each release records the exact source dates and preparation details for the published map data.
  • The updater writes file checksums and a manifest into one server-ready release update. The web application validates the update before activation and reads the published files for map display and assessment.
  • The map draws its coverage and context layers from the PMTiles or GeoJSON files included in the published map data.
  • The deployed release preserves the exact lockfile notices, source dates, required attribution, and any applicable ODbL or extract-provider obligations.

Web release: 2026.08.22-alpha.7.8.2-bundle-limits-coverage-zoom-pantry-names