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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, preparation tools, and limitations used by the Illinois Grocery Access tool. The active bundle manifest records the exact source dates and preparation details for each release.

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; the active bundle manifest and release record should be used for a specific analysis.

USDA SNAP retailer data

The desktop updater downloads Illinois records from the USDA SNAP authorized-retailer source. The bundle 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 overrides also apply.

USDA SNAP retailer data

Illinois WIC vendor data

The desktop updater uses Illinois WIC's operational public store locator by default. A validated agency-supplied CSV can replace that snapshot. The active bundle 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

CDC PLACES and community health context

Where included in an active bundle, 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 belong to the active bundle manifest.

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 renders the map and bundled PMTiles or GeoJSON layers. 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 active bundle; 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 updater writes checksums and a manifest into one server-ready release bundle. The web application validates the bundle before activation and reads the active files for map display and assessment.
  • Administrative store reviews can override classification or hours after publication. Those overrides are separate from the source data and should be 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.

Licensing and notices

Open-source software and public-data terms remain with their respective authors and providers. The deployed release should preserve the exact lockfile notices, active-bundle manifest, source dates, required attribution, and any applicable ODbL or extract-provider obligations. See the project third-party notice file for the release checklist.

Web release: 2026.08.01-v8.10.5-platform