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Show HN: OpenTimes – Free travel times between U.S. Census geographies

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Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#41

Post by bobthepanda »

dfsnow wrote: post #17
bobthepanda wrote: post #7

Any plans on adding public transit?

In the next year or so maybe. The biggest obstacles to adding public transit are: - Collecting all the necessary scheduling data (e.g. GTFS feeds) for every transit system in the county. Not insurmountable since there are services that do this currently. - Finding a routing engine that can compute nation-scale travel time matrices quickly. Currently, the two fastest open-source engines I've tried (OSRM and Valhalla)…

I would imagine actual nation scale public transit would be relatively difficult since even in the Northeast transit networks are often not contiguous

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#42

Post by svcphr »

dfsnow wrote: post #32
svcphr wrote: post #29

How did you decide on routing engine? I’ve used Graphhopper in the past — is OSRM an improvement?

I actually tried a couple different engines before landing on OSRM. I started with R5 (since it can also do public transit) then switched to Valhalla. The main limiting factor was speed. Basically all routing engines except for OSRM are too slow to compute continent-scale travel time matrices. For reference, it took Valhalla around a week to finish 3 billion point-to-point pairs. OSRM did the same calculation in abou…

Makes sense! Heads up that Graphhopper’s matrix algorithm isn’t open sourced so probably won’t work for this use case. I’ve had good experiences with it otherwise.

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#43

Post by kalendos »

dfsnow wrote: post #20
simonw wrote: post #15

OK the way you're publishing the data with Parquet and making it accessible through DuckDB is spectacular . Your README shows R and Python examples: https://github.com/dfsnow/opentimes?tab=readme-ov-file#using... I got it working with the `duckdb` terminal tool like this: INSTALL httpfs; LOAD httpfs; ATTACH 'https://data.opentimes.org/databases/0.0.1.duckdb' AS opentimes; SELECT origin_id, destination_id, duration_se…

Thanks! I hadn't seen anyone do it this way before with a very large, partitioned dataset, but it works shockingly well as long as you're not trying to `SELECT *` the entire table. Props to the DuckDB folks. Eventually I plan to add some thin R and Python wrapper packages around the DuckDB calls just to make it easier for researchers.

Nice! I know a couple of projects that have been using this pattern.

- https://bsky.app/profile/jakthom.bsky.social/post/3lbarcvzrc...

- https://bsky.app/profile/jakthom.bsky.social/post/3lb4y65z24...

- https://skyfirehose.com

Love this distribution pattern. Users can go to the Parquet files or attach to your "curated views" on a small DuckDB database file.

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#44

Post by kalendos »

c_moscardi wrote: post #5

Amazing! GitHub actions to compute a giant skim matrix is an incredible hack. I pretty regularly work with social science researchers who have a need for something like this... will keep it in mind. For a bit we thought of setting something like this up within the Census Bureau, in fact. I have some stories about routing engines from my time there...

Totally! I've been using this pattern a lot and recently wrote about it.

https://davidgasquez.com/community-level-open-data-infrastru...

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#45

Post by lotsofpulp »

Cool project! For me, seeing commutes time for 1 and 2 standard deviations would be useful too. Many times, people like to convey the lowest travel times, when I am more interested in the amount of time I need to budget to travel between two places to be on time 95% of the time.

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#46

Post by lotsofpulp »

bobthepanda wrote: post #7

Any plans on adding public transit?

I feel like this would have to come from Apple/Google, due to them having numerous real time datapoints on the time it takes from the origin public transit stop to the destination transit stop.

And then they could determine the variance at certain times of days for certain public transit routes, and show your likelihood of reaching the destination by a certain time.

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#47

Post by jarpineh »

This is a wonderful project. Seemingly simple on the surface. I'd love to see some notes of the frontend implementation. I see there's OpenFreeMap as presumably the base map, which uses MBTiles. Then custom geometry on top from Pmtiles, that I assume is generated for the project. How the colormapping is done I didn't find yet. Actually lots to unpack here.

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#49

Post by balderdash »

This is a fantastic project , and well done! How are you thinking about implementing traffic (it feels like that’s obviously essential for most practical use cases)?

Also just so I’m clear, is the shading corresponding to a time the represent mean travel time for the area, or the max travel time? E.g. if you pick Walking, and a neighborhood next to Central Park in New York City, even Even though parts of Central Park are directly adjacent to that neighborhood and should be a short travel time. The entirety of Central Park is shaded with a longer travel time, Does this mean I could theoretically get to the furthest point away from the selected area in Central Park in that travel time or is that more of like a mean travel time within that area and some travel times will be shorter or longer?

Re: Show HN: OpenTimes – Free travel times between U.S. Census geographies

#50

Post by drchickensalad »

itissid wrote: post #16

Travel time context in general could be useful for retrieval before ranking in searches like Yelp or Google maps like products for nearby events and places. My MVP use case is to configure a rerank based on commute "score". For example there is just no way I'm going to commute from Brooklyn to Manhattan on a Monday night to eat out. I live across the river from Manhattan and what I never understood was why yelp and G…

I love how much this affects people on dating apps too, lol.
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