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Interactive visualization of commute times for all US cities

trulia.com

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Re: Interactive visualization of commute times for all US cities

#21

Post by ImprovedSilence »

whalesalad wrote: post #15

This is the most worthless chart I've ever seen. When would this be useful? It's roughly the same everywhere. Before I am downvoted into oblivion... honestly can someone explain to me when they would ever reference this chart? Give me one good example.

If it was accurate, it would be very helpful if, say, I got a new job, or was looking to relocate areas for a job, I could pick out neighborhoods I'd want to live in based off of commute times to my new workplace. And if I knew where I thought I wanted to live, I could see if it would be too far to work.

or if I was on travel, and had a meeting at a client site at point a. but a hotel near my companies office at point b, I could see the travel times, and maybe even go for a hotel closer to point a (or hotels near point a are too expensive, how far would cheaper hotels be for my commute) .

Re: Interactive visualization of commute times for all US cities

#22

Post by elliottcarlson »

whalesalad wrote: post #15

This is the most worthless chart I've ever seen. When would this be useful? It's roughly the same everywhere. Before I am downvoted into oblivion... honestly can someone explain to me when they would ever reference this chart? Give me one good example.

If someone is looking to relocate to a new (and thus unfamiliar) location and they need to figure out how far they would comfortably be willing to live based on commute times vs. cost of living.

Re: Interactive visualization of commute times for all US cities

#23

Post by Yen »

nostromo wrote: post #16
shashashasha wrote: post #2

Hi, Sha from Trulia here. I worked on some of the frontend aspects of this visualization and would be happy to answer any questions. We're pulling in OSM road data and published GTFS files for public transit routing. I just linked to SF but you can also search for other cities: http://www.trulia.com/local#commute/new-york-ny http://www.trulia.com/local#commute/miami-fl http://www.trulia.com/local#commute/austin-tx

This is super cool! It's more of a backend question, but what algorithm are you guys using to traverse the maps? Also, why did you decide to use Google for the display maps, when you used OSM for the backend calculations?

Hi, Talin from Trulia.

The times are calculated with a simple Djikstra's traversal, implemented in the open-source pgRouting (pgrouting.org)

Our existing local information pages were already using google maps, so we didn't go out of our way to create new base maps just for this visualization.

Re: Interactive visualization of commute times for all US cities

#24

Post by rburhum »

Most people are missing some of the most amazing stuff here. First, how the slider works without refreshing the tiles. They have tiled the travel costs http://tiles.trulia.com/commute/time_map/data/driving/37.774... and are drawing these changes without having to refresh the map. That's cool. Secondly, they have used Openstreetmap for calculating travel time. I cannot imagine OSM having a street segment cost that is too accurate, so it was probably derived from pure geometry (think about it... traversing .25miles in downtown SF has a much higher cost than .25 miles on the 5 freeway). If instead, you used a Navteq or Teleatlas dataset for this, I bet the isochrone polygons would come out much more accurate. My hats off to the Trulia team, this is good stuff.

Re: Interactive visualization of commute times for all US cities

#25

Post by jmduke »

ImprovedSilence wrote: post #18

I think it's a very awesome idea, and I'm impressed with the visuals. However it seems that several people on here are claiming wildly inaccurate commute times, and I myself have noticed this as well. I think part of the problem is that it is hard to get a full understanding of what rush hour traffic is like, and that the actual volumes of traffic and slowdown differ depending on locality and road. Sever places, incl…

Agreed. The visualization concept itself is really great, but the data seems wildly incorrect in places.

Re: Interactive visualization of commute times for all US cities

#26

Post by Yen »

ImprovedSilence wrote: post #18

I think it's a very awesome idea, and I'm impressed with the visuals. However it seems that several people on here are claiming wildly inaccurate commute times, and I myself have noticed this as well. I think part of the problem is that it is hard to get a full understanding of what rush hour traffic is like, and that the actual volumes of traffic and slowdown differ depending on locality and road. Sever places, incl…

Hi, Talin from Trulia here.

As many commentors have pointed out, our time-accuracy is not exactly 100% yet. :)

This is our first iteration on this concept, so we are using some heuristics to try to get times roughly close, and accurate relative to each other. We're also validating the user experience, value as a product, etc.

I'm still investigating a good set for nationwide traffic data, which will help give us a much more accurate picture of real-world commute times. Traffic varies so very much city to city :)

Re: Interactive visualization of commute times for all US cities

#27

Post by [deleted] »

nostromo wrote: post #16
shashashasha wrote: post #2

Hi, Sha from Trulia here. I worked on some of the frontend aspects of this visualization and would be happy to answer any questions. We're pulling in OSM road data and published GTFS files for public transit routing. I just linked to SF but you can also search for other cities: http://www.trulia.com/local#commute/new-york-ny http://www.trulia.com/local#commute/miami-fl http://www.trulia.com/local#commute/austin-tx

This is super cool! It's more of a backend question, but what algorithm are you guys using to traverse the maps? Also, why did you decide to use Google for the display maps, when you used OSM for the backend calculations?

[deleted]

Re: Interactive visualization of commute times for all US cities

#28

Post by Yen »

MetalMASK wrote: post #20
shashashasha wrote: post #2

Hi, Sha from Trulia here. I worked on some of the frontend aspects of this visualization and would be happy to answer any questions. We're pulling in OSM road data and published GTFS files for public transit routing. I just linked to SF but you can also search for other cities: http://www.trulia.com/local#commute/new-york-ny http://www.trulia.com/local#commute/miami-fl http://www.trulia.com/local#commute/austin-tx

Hi Sha, Great work. I checked commuting time for Seattle, WA using public transit and most of your visualization are spot on. Is the public GTFS files you are referring to come from here: http://code.google.com/p/googletransitdatafeed/wiki/PublicFe... ? With regard to some of the earlier replies saying that the map is inaccurate, it might be worthwhile to use Amazon Turk to run some evaluation on how reliable the spa…

We retrieved a list of U.S. agencies with GTFS feeds from gtfs-data-exchange.com, which is a very excellent resource :)

Re: Interactive visualization of commute times for all US cities

#29

Post by wiredfool »

bryanjclark wrote: post #10

Great concept, but I think there are a lot of data errors here. (In Seattle, a drive I take about 5 minutes to make was listed as taking an hour!)

Yeah, I'm seeing consistent ~3x times in my location outside Seattle (a rural, no traffic sort of place). Within Seattle, well, Downtown to Magnolia doesn't take an hour.

It really looks algorithmic based on street size, assuming some specific congestion level. I'm not seeing any indication of some of the known congestion points that I used to have to deal with.

Re: Interactive visualization of commute times for all US cities

#30

Post by Yen »

exue wrote: post #9

Question: Is the pointer the start location or the end location of the commute? It wasn't immediately obvious to me and in many areas it makes a huge difference. It seems like it's just pulling worst case "in traffic" drive times right now. Also is it possible to adjust the time of day that one commutes? (since many may work shifts off rush hour and encounter little/no traffic or strange/intermittent transit schedule…

On the large scale, you get pretty much the same map whether you're calculating 'to' the marker or 'from' the marker. The only exception is if you plan on commuting in the opposite direction of rush hour traffic, both ways.

i.e., if you think about commuting to work in the morning, the heatmap will show you the times it takes to drive from any given location to the marker. If you're thinking about driving home in the evening, you can think of the time from the marker to any given location.

on the macro scale, most streets aren't one-way, and commute times tend to be symmetric.

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