Find the flattest route between any two points in SF

Checkout https://bikehopper.org for solid elevation, bike infrastructure and transit-aware routing around the Bay Area. Some friends and I built this about 5 years ago and continue to maintain it. We use 1m DTM elevation data for SF and 50m for rural areas. DTM is a must for elevation based routing in SF as there are so many sizable buildings, large trees the other models fail hard. reply: Very Cool. Thanks for making it!I've checked out a few bike mapping apps recently and one feature I found absolutely invaluable was grade indications like http://hillmapper.com (which unfortunately seems unmaintained.)Google Maps elevation diagrams comparing the various selected routes are nice but they do not do a good job of highlighting extreme grades. I feel like you actually want to graph the change in elevation rather than the elevation itself.Using a route I cycled the other day (near Mission Bernal Safeway to near Diamond Heights Safeway). I think the routing may overweight bike lanes too much....

It would be neat if it there were an option which added distance and elevation gain, but minimized the grade.For example, a route from SOMA to Nob Hill can be made flatter by approaching from either the east or west. Technically the "flattest" as measured by elevation gain between the two is straight up Taylor from Market, but it's much nicer to bike to the top of Nob Hill by going out of the way (e.g. Polk → California, Embarcadero → Broadway, etc.) reply: I suspect that this would result in absurdly long routes. Imagine trying to go up a mountain while minimizing grade... you'd end up zig-zagging back and forth endlessly.

It's not accurate. I mapped it from my house on Cabrillo St in the outer Richmond to 4th avenue and it says I need to climb 25th avenue then walk Geary instead of correctly telling me to use 23rd avenue that is completely flat. reply: I think this comes down to the DEM they are using. I think it would have come out better if they had used USGS 3DEP DTM at 25cm.Edited: which apparently is hosted for free on AWS S3.

The wiggle!(in honor of my old commute, which I miss)https://flattensf.com/#t~-122.40850~37.77493~-122.50940~37.7...

There's a weird thing going on at 22nd and San Jose in the Mission, where it doesn't seem to understand that you can simply continue down 22nd, but instead takes a hook down San Jose before backtracking. I see some other weird discontinuities like this as I click around.I have to say that the Claude UI has made many inexplicable decisions here, including (but not limited to) the mysterious color coding, the confusing continuous slider over a discrete set, and the weird positioning of the height labels in the altitude graph.

This seems to have the same issue I saw with Google Maps where it directed me along 29th St from near Mission Bernal Safeway to Diamond Heights Safeway. This includes a 22.7% grade! It's much faster and easier (at least on my cargo e-bike) to take the longer way around up Clipper St (12% grade).The bug seems to be apparent when you set the end point at Duncan & Diamond Heights Blvd and the start point directly north along Clipper.This route seems to maybe save 1 ft of climbing but goes up a 23% grade.https://flattensf.com/#t~-122.43968~37.74865~-122.44028~37.7...Half a block up the street it takes the sensible route with only a 13% grade. (Between the two different starting points is 41ft of climbing.)https://flattensf.com/#t~-122.44087~37.74864~-122.44028~37.7... reply: good point.. the slider trades distance against total climbing and nothing else. steepness is currently reported but not optimized.seems like a worthy addition to the objective!

It's telling me to bike on Geary and Divisadero. No thank you I'd rather stay alive. reply: fair point! it just doesn't know about bike lanes yet, I’ll see about getting the SFMTA bikeway network map from DataSF.

This is great. Since SF is mostly a grid, I used to use the heuristic of only choosing paths that wouldn't take me further from my destination, avoiding going downhill but choosing the shallower uphill climb if a choice is given.Other than knowing the direction of my destination, it only used local information

Would love an option for the steepest route! I run a lot in SF and try to maximize vertical gain on my routes

Cool, I used to build this https://github.com/cheeaun/steepless (2014)

Absolutely love the live profile updating when you swipe from flatter to shorter.

someone should make flattendallas.com as a joke

> The slider runs along the whole trade-off between distance and climbing [...] Climbing is cumulative gainAnother mechanism might be a kind of user-defined cost-curve, where a gradual climb to 10 might be preferred over a steep climb to 8, etc.

You should consider adding drive as well, some of us have manual transmissions still, although the Bike mode returns pretty reasonable results.

you could mathematically find the least bikeable city using this lol

Sorry if this is a stupid question, but isn’t the climb independent of the route?

Doesn't Google Maps in bicycle mode already do this?

Cool! Any way to toggle on street names on the map?

Try downtown to somewhere in Bernal, say Progressive Grounds coffee house.The flattest route is only 0.2 miles longer than the shortest, but goes from 200ft of climbing to 500ft of climbing, 12% max grade to 22% max grade.Apple maps picks the shortest every fucking time.