Waterway Map

Original Article ↗ Hacker News Discussion ↗

A new OpenStreetMap‑based tool, WaterwayMap.org, visualizes rivers, canals, and connected water systems worldwide and lets users filter them by criteria such as “navigable by boat” or “navigable by canoe.” Commenters praise it for revealing long-distance routes and historical canal networks, but note that the navigability filters often miss real-world waterways because they depend on sparsely used OSM tags and don’t distinguish well between legal, seasonal, and practical navigation. Many see it less as a navigation aid and more as a powerful quality‑assurance and exploration tool for improving OSM data and understanding how water shapes geography, settlement, and travel.

Data Source and Purpose

  • Map is generated entirely from OpenStreetMap (OSM) data and updated daily.
  • Primary intent is visualizing waterway connectivity and acting as a QA tool for OSM, not as a navigation chart.
  • A separate tool (osm-lump-ways) computes river systems and total connected lengths.

Canoe/Boat Navigability Filters

  • Many users find “Navigable by canoe” and “Navigable by boat” filters overly sparse or missing obvious waterways.
  • Explanation: these views only show features with specific OSM tags (canoe, boat, motorboat), which are often absent or inconsistently applied.
  • Users are encouraged to edit OSM to add missing tags; fixes propagate to WaterwayMap quickly.
  • Several note that “legally navigable” vs “practically navigable” diverge (e.g., rivers with rights of navigation but no working locks or dangerous sections).

Data Quality, Gaps, and Topology Issues

  • Coverage is highly uneven: some tiny ditches and intermittent arroyos are mapped, while significant rivers or waterfalls are missing.
  • Users report:
    • Disconnected tributaries, streams ending at shorelines, and breaks at lakes/estuaries due to unclear OSM conventions.
    • State or jurisdiction boundaries where mapping abruptly changes density.
    • Under-mapped regions (e.g., much of Asia, some US wilderness, parts of Canada) and over-detailed ephemeral streams in arid areas.
  • Ongoing OSM debates exist on whether to draw river centerlines through lakes and large water bodies.

Regional Observations

  • California/Sierra–Bay Area: discussion of theoretical canoe routes to the Bay, complicated by dams, reservoirs, underground pipes, and rapids, but historically and currently boats do connect the Central Valley to the ocean.
  • UK & Europe:
    • Enthusiastic comments about canals and narrowboat life; English/Welsh canal network (~2,500 miles) is well represented and used for leisure travel.
    • Users point out specific errors (e.g., Mersey missing as boatable, odd gaps on the Soar and Dee).
  • Other regions mentioned: Yucatán’s underground cenotes (appear empty on the map), New Mexico arroyos, Toronto’s “lost rivers,” Minnesota’s Boundary Waters, Sahara dry riverbeds.

Related Tools and Comparisons

  • Users link complementary tools: watershed calculators, “river runner,” sea charts (OpenSeaMap), rail and cycle overlays, and specialized canal maps.
  • Some note that these other tools may be more suitable for real-world navigation, while WaterwayMap excels at visualizing and debugging waterway networks.