Find The Flattest Route Between Any Two Points In SF
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Flatten SF, a web tool by Drew Edwards, calculates routes between San Francisco locations and lets users explore the trade-off between distance and climbing. The site says it uses USGS one-meter lidar elevation data and an Overture/OpenStreetMap street graph; it does not provide independent route accuracy results.

Drew Edwards has published Flatten SF, a browser-based tool that finds routes between San Francisco locations and lets users compare distance with cumulative climbing. The site says its calculations use USGS one-meter lidar elevation data and a street network assembled from Overture and OpenStreetMap data.

Users enter starting and ending locations and adjust a slider to move among routes that balance walking distance and elevation gain. According to the site, the options span from the shortest route to a flatter route that may require more walking. Moving the slider right does not shorten the route or increase climbing, the site says.

Flatten SF describes the displayed options as routes that are not beaten by another route on both distance and climbing. The tool counts cumulative elevation gain, rather than simply comparing the elevation at the start and finish. It also displays faint lines for other routes along the trade-off.

The site says route calculations run in the user’s browser across more than 160,000 street segments. Place search works offline, using San Francisco intersections, places and addresses built into the page. Stairways are included for walking routes and excluded for bicycle routes, according to the site’s explanation.

At a glance
announcementWhen: Available on the Flatten SF website; pu…
The developmentDrew Edwards has published Flatten SF, a browser-based tool for comparing walking or biking routes across San Francisco by distance and elevation gain.

Choosing Between Climbing and Distance

San Francisco’s steep streets can make two routes of similar length feel quite different. By presenting distance and cumulative climbing together, Flatten SF gives users a way to inspect that trade-off before setting out, rather than relying on route length alone.

The tool may be useful for people who want to limit uphill effort, as well as those who prefer a shorter trip. Its route choices also make the cost of a flatter path visible in additional distance. The site characterizes one end of its slider as the flattest route worth walking, using a model in which a foot of climbing is treated as equivalent to 200 feet of walking. That is a design choice described by the site, not a universal measure of how difficult a route will feel.

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How Flatten SF Builds Routes

The page credits its elevation input to USGS one-meter lidar and its street graph to Overture and OpenStreetMap. It says routes are computed in the browser, with search data for San Francisco included in the page. The site also links to its source, data and full analysis.

The stated 200-foot walking equivalent sets the point where the slider’s flatter options stop being considered routes by the tool. The calculation measures total climbing along the way, so a route that ends at roughly the same height where it started can still have substantial elevation gain. The site says stairs are permitted when routing on foot, but omitted for bicycle routing.

“every route that nothing else beats on both counts, from the shortest path to the flattest one worth walking”

— Flatten SF website

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Route Accuracy and Coverage

The site explains the data sources and method, but the supplied material does not report independent testing of route accuracy or how often the suggested paths match current street conditions. It also does not state when the tool was published or provide figures on its use.

It is not clear from the available description how the tool handles temporary closures, construction, accessibility barriers or other conditions that may change the practical suitability of a route. Users should treat the displayed options as calculations from the stated map and elevation inputs; the site description does not establish that every route has been checked on the ground.

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Source Data and Further Analysis

Flatten SF directs readers to its source code, data and full analysis for further detail on how the routing works. The supplied report does not announce a release schedule, planned features or subsequent updates. Whether the route data will be refreshed, and how changes to streets or access will be reflected, remains unstated.

Readers can try routes between San Francisco locations on the site and compare the distance and climbing figures. For trips where current access or conditions matter, they will need to check those details separately.

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Key Questions

What does Flatten SF do?

It calculates routes between San Francisco locations and lets users compare options by distance and cumulative climbing.

What data does the tool use?

The site says it uses USGS one-meter lidar elevation data and a street graph from Overture and OpenStreetMap. It reports computing routes in the browser over more than 160,000 street segments.

Does it include stairs?

According to the site, stairways are allowed on foot routes and excluded from bike routes.

What does the route slider compare?

It shows routes along a trade-off between distance and cumulative elevation gain. The site says moving right never shortens a route or adds climbing.

Does the site verify current street conditions?

The supplied description does not say whether temporary closures, construction or accessibility barriers are checked against current conditions.

Source: hn

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