Map sources

This map uses satellite imagery with numbered geographic features, municipal boundaries, and river and canal centerlines. Feature data was retrieved in September 2026.

Satellite imagery

Satellite tiles come from Esri World Imagery. Image dates and providers vary by location and zoom. Attribution: Esri, Vantor, Earthstar Geographics, and the GIS User Community. The images are not a live feed and require an internet connection. Imagery is streamed from its provider; it is not included in the downloadable geographic data below.

Geographic features

Geographic data is derived from OpenStreetMap contributors, licensed under the Open Database License (ODbL). Source geometries were retrieved through Nominatim: lake responses on September 3, 2026; municipal limits, connecting waters, and canals on September 8, 2026. Download the derived map data and feature coordinates (JavaScript containing JSON, ODbL).

Coordinates are WGS84, longitude then latitude. Leaflet displays the map in Web Mercator (EPSG:3857), north up, with a local metric scale. Topology-preserving simplification tolerances were 0.001° for lakes, 0.0005° for municipal boundaries and Lake St. Clair, and 0.00025° for river and canal centerlines. Polygon holes are preserved.

Municipal outlines show legal city limits, which can include water; they are not urban footprints. City numbers use city-center coordinates inside those boundaries. Connecting-water and canal numbers are anchored to their source centerlines. These features are suitable for regional orientation, not surveying or navigation.

Fox River means the lower Wisconsin river entering Green Bay. The Chicago canal number sits near Lockport. The Welland Canal number follows the active canal near Port Colborne. The St. Lawrence Seaway number locates one river reference point east of Lake Ontario; it does not represent the whole seaway system. The St. Clair River is connecting geography without a separate question.

Route cross-checks: the Seaway authority’s Welland Canal map and locks and channels overview; the Library of Congress Chicago canal survey; and Michigan EGLE’s Detroit River overview.

Software and type

Leaflet 1.9.4 handles the map, zoom, projection, and overlays. A copy of its BSD 2-Clause license is included. Outfit is bundled locally under the SIL Open Font License.

Scores and sound

Points reset each round. Your accumulated practice history and personal bests stay in your browser; clear them under Map info → Your practice or Leaderboards → This device. If browser storage is unavailable, these records last only while the page stays open.

Time me connects to the game’s scoring service, which records the round’s answers, score and elapsed time. At the end of an unassisted full-map round, you may choose a nickname and post your result to the shared leaderboard. Posting is optional; nicknames, points and times are public once posted. Use a nickname that does not identify you. An anonymous browser cookie associates your posted best with this browser, so clearing cookies or using another device creates a separate identity. No account or email address is required. Explore, Reveal, or a lost scoring connection makes the round ineligible for the shared board; you can still finish playing.

Unfinished rounds expire after two hours; completed round records expire after seven days. Posted bests remain until removed. Temporary hashed request identifiers help limit spam; raw IP addresses are not stored in the game database.

Sound effects are synthesized locally using Web Audio. Fireworks honor reduced-motion settings, and the finish chime honors mute. Opening this sources page leaves the round open in its original tab.

The link-preview image is a screenshot of this game, including the map provider attribution.