Data Sources & Attribution

OpenStreetMap and mapping licenses

Maps may use OpenStreetMap contributors’ cartographic data under ODbL. When community tile servers are used, attribution must remain visible and tile-usage requirements apply. Community tile hosting is not a free unlimited commercial service.

OSM copyright & licensing · Tile usage policy

Map libraries and geodesy

Leaflet renders responsive maps and vector layers. JavaScript calculations use coordinate geometry and standard conversion constants. Circle exports use polygons to make the geometry compatible with GeoJSON or KML. Developers can inspect the underlying library documentation for supported methods.

Leaflet reference · GeoJSON RFC 7946

Geocoding and route data

If enabled by the website operator, typed address searches may use Nominatim through a rate-limited server proxy. Travel-time isochrones can use OpenRouteService when an administrator provides an API key. Availability and legal usage depend on each provider’s terms. No provider is assumed to be active just because a field appears in the interface.

Nominatim policy · OpenRouteService

Population, postal and boundary sources

US Census data portals are potential references for official population counts, geographic hierarchies and ACS survey estimates. USPS ZIP codes differ from US Census ZCTAs. Any imported dataset should carry the author, licensing terms, publication year and matching method; this plugin does not bundle official ZIP counts or a nationwide household-level population dataset.

US Census APIs · Census ZCTA definition

Measurement standards and public regulations

Conversions use standard international statute-mile, nautical-mile and acre definitions. The 150-air-mile short-haul topic refers readers to official FMCSA materials; this website does not certify compliance.

NIST · FMCSA

Third-party comparisons

Competitor names and domains are listed for informational research and navigation only. Feature lists may change. See radius map alternatives and confirm capabilities on each provider’s official website.

Population and ZIP data provenance

Official US Census statistical products can support population analysis, but custom-radius estimates require a spatial allocation rule and documented data vintage. USPS ZIPs and Census ZCTAs are different systems.

The current configurable CSV format uses ZIP representative coordinates. It should not be labeled exact Census block intersection. If no source has been uploaded, a population or ZIP result cannot be displayed.

Maps, geocoding and route providers

OpenStreetMap supplies geographic map data and contributors’ attribution. OSM community tile servers and Nominatim impose separate acceptable-use rules. OpenRouteService provides routing services under documented quotas and profiles.

When a commercial geocoder, aerial map imagery provider or other vendor is enabled, the actual deployment policy must be updated with the new vendor and permitted use of its data.

Units and interoperability standards

The international statute mile is exactly 1.609344 km. A nautical mile is exactly 1.852 km. An international acre is 43,560 square feet. These constants can be checked against NIST and international measurement references.

For GeoJSON coordinate order, polygon conventions and supported geometry types, consult RFC 7946. KML is a geographic interchange format but exported geofences are not device alert configurations.

Optional ZIP source, license and reference years

The one-click ZIP import uses ReadyAPIs curated-us-zips, released under Creative Commons Attribution 4.0. The source includes ZIP representative coordinates and selected enrichment fields. Its upstream population values are not all necessarily from the same Census year, so the plugin does not relabel them as an official 2020 enumeration. For official ZIP Code Tabulation Area methodology, see US Census ZCTA documentation.

Official mapping and regulatory references

Distance/area unit conversions follow international definitions, including 1 statute mile = 1.609344 km and 1 nautical mile = 1.852 km. For legal US air-mile rules, the primary text is 49 CFR §395.1. Geographic map tiles and place-search data may originate from OpenStreetMap contributors subject to their attribution and usage terms. Route isochrones are available only when a legitimate routing key and supported profile are configured.

External competitors and editorial independence

Links to independent mapping providers appear for comparison, instruction and source transparency. Their product behavior, pricing, availability and API policies may change without notice. Descriptions should be periodically verified on the vendors' own documentation; this site does not endorse or represent those companies.

Primary sources and version-specific limitations

For US population geography, prefer official Census datasets and clearly separate Decennial Census counts from American Community Survey estimates. For ZIP-related mapping, the Census ZCTA boundary documentation describes statistical geography rather than postal delivery assignments. For road-network catchments, record the routing provider, transport profile, request time and any assumed speeds.

Map libraries supply drawing and arithmetic capability but are not themselves a source of current demographic counts, legal boundaries or traffic. An address search provider can resolve an approximate coordinate that differs from an official parcel corner. Our results should expose these limitations and not pretend the presence of a brand name on a map is a certification.

Worldwide population and ZIP lookup references