Find the flattest route between any two points in SF
FlattenSF is a browser-based routing tool for San Francisco that calculates paths balancing distance against cumulative elevation gain using lidar and OpenStreetMap data.
summary is enough The tool is a neat geographic utility for San Francisco, and the comment thread provides useful technical context on elevation data and routing flaws.
summary
FlattenSF helps pedestrians and cyclists find routes in San Francisco by sliding between the shortest path and the flattest one using USGS 1m lidar and OpenStreetMap data. The tool computes routes locally in the browser, tracking cumulative elevation gain. Commenters highlight routing bugs and suggest adding maximum grade constraints to avoid dangerously steep segments. Others share alternative Bay Area routing projects and discuss elevation data precision.
key points
- Uses USGS 1m lidar elevation and Overture/OpenStreetMap street graphs to compute routes entirely in the browser.
- Features a slider that balances distance against cumulative elevation gain rather than net height difference.
- Commenters note current limitations, such as routing bugs with pedestrian-only tags and the lack of maximum-grade constraint optimization.
who should read it
San Francisco residents, cyclists, pedestrians, and geospatial developers interested in custom routing engines.
discussion positive
consensus
Commenters appreciate the tool for navigating San Francisco's hills, but note specific routing errors and missing features like maximum grade thresholds.
pushback
Some users point out bugs where pedestrian zones are misread or routes direct users onto dangerous high-traffic streets.
ah, I think this is related to SF's "Slow Streets" program and a genuine bug in the parser.
Cabrillo is a Slow Street, and the parser read its "destination-only" tag as closed to pedestrians, so the tool couldn't see the street at all (and started you a block over?). fixed and deployed; your trip should now go Cabrillo → 23rd → Geary.
The creator rapidly diagnoses and deploys a fix for a parser bug live within the Hacker News thread.
Generated by an LLM from the article and thread. Check the sources before relying on it.