OpenStreetMap

What's up with Philadelphia?

Posted by wallclimber21 on 4 October 2009 in English (English)

keepright ( http://keepright.ipax.at ) is the single most important tool in the bag of open street map tricks, and pretty much the only reason I'm starting to believe that OSM may one day have a modest shot at being useful for routing (the lack of house numbers rules out a top-notch experience, IMHO). And now it's available for the US too. Woohoo!

The starting point of the keepright checking algorithm was in Philadelphia, so that's what popping up for first time keepright USA users.

If you ever needed proof that OSM is currently NOT ready for general routing use, look no further.

What A Mess...

US Interstates are often the first ways to be corrected (largest ! for $), but somehow Philadelphia didn't receive its share of TLC. It has interstates going straight through the city center, either on elevated structures over the local streets or in these huge ditches with local streets crossing above, but pretty much all of them have a junction as if they were intersection. You know: speed down on I-76 at 75 mph, next take a sharp turn right onto 21st St. Fun, fun, fun.

It's obviously no easy to have so many over- and underground highways, but you'd think that a city this size has at least some OSM fanatics to clean thing up?

Anyway, I've fixed up a large section of the downtown I-76 intersections, but some are too obscure to get a decent insight (like the one this post is linking to.) Let's get to work!

(And, please, whenever something is fixed, mark it as such on keepright.)

Location: Rittenhouse, Philadelphia, Pennsylvania, 19103, United States of America

Comment from robert on 5 October 2009 at 01:18

"If you ever needed proof that OSM is currently NOT ready for general routing use, look no further."

Please don't extrapolate your US experience to the whole of OSM. My area of the UK routes bloody well, thankyou. Most of the south of England does too.

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Comment from wallclimber21 on 5 October 2009 at 01:40

I know this is the Internet and all that, where emotional reactions are the norm, but, dude, relax.

If you say "most of the south of England does too" may I conclude that some part of England don't work so well?

I'd like to refer to one reactions to a presentation that was made at the State of the Map conference: the problem with OSM data is not that the quality is always better worse that, e.g., the one you can license from the Ordnance Survey. (It is, in fact, in some place quite a bit better.) It's that you don't know where it's good and where it's bad.

If I'm a technology luddite who lives in Silicon Valley or San Francisco and buy an OSM based navigation app, my experience when driving around locally will be almost stellar. But when I then hop on a plane to use the same app in, say, Philadelphia, my experience will be horrible.

The same thing is true for Belgium, where I've correct tons of errors around my previous stomping grounds. Top notch quality in Antwerp, Louvain and Brussels. Pretty much nothing wrt local street the moment you dare to take a 30 minute drive. Correlation with the presence of high quality Yahoo Aerial images is 99%, of course.

Replace "Silicon Valley" with "South of England" and "Philadelphia" with "some other place in England where coverage is bad" if a US experience hurts your sensibilities, but surely you get my point.

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Comment from Mappo on 5 October 2009 at 11:23

I think the subtlety was in the use of the word "general". It is sometimes used as a meaningless filler word but you're using it correctly to mean OSM routes well in some places, badly in others. Which is hard to argue with, when stated like that.

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Comment from robert on 5 October 2009 at 15:08

"If I'm a technology luddite who lives in Silicon Valley or San Francisco and buy an OSM based navigation app, my experience when driving around locally will be almost stellar. But when I then hop on a plane to use the same app in, say, Philadelphia, my experience will be horrible."

That's great. But I'm afraid this situation will always be true because OSM will never cover everywhere fully. No map will. There will always be somewhere that isn't covered fully. There are plenty of places that google maps covers poorly or not at all. You cannot just go anywhere in the world and trust that google will have accurate coverage for where you are. That's not how it works.

"currently NOT ready for general routing use" is the same class of phrase as "(linux is) currently NOT ready for the desktop". It is a misrepresentation of what the problem actually is, and that's why it's annoying. It's a meaningless phrase that just floats around forever, giving a general bad impression of the project but never actually being resolvable.

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Comment from wallclimber21 on 5 October 2009 at 17:04

The key with Linux is that I know up front what will work and what won't. If I place the right icons at the right place on the desktop, my mother could switch with little or no disruption.

When you buy a US version of a Garmin navigator, you don't expect it to work great in Sydney. OSM doesn't have to be perfect for the whole world, but there should be some kind of expectation management. A way to indicate that data in a certain region is just to low quality to bother using it for turn-by-turn routing.

Now there is an important difference between the US and the rest of the world. We have TIGER data, so in terms of street graph, OSM is almost complete. All that needs to be done is to verify that the coordinate, intersections and one-ways are correct. The good thing is that one can now correct major parts of a city without ever being there, but it's even less obvious when quality is bad so you don't depend as much on whether or not somebody local lives there.

Seeing how OSM has changed in just the short 10 months since I joined, there is no reason to be defeatist about the current state of affairs. My diary post was a call to action, not one to give up. The beauty of maps is that the data is that they are so very static, so time is in our favor.

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