Comments on: Comments On The Routability of OSM Data

By: ij

ij — Tue, 02 Mar 2010 12:02:48 +0000

Thanks for the answer Bobby,

Based on that it seems that we would be able to infer much more than those 1300 restrictions, assuming access=no and psv=yes markings would be correctly set on all “South streets” (that of course depends heavily of the state of the map in a particular area, I’m not claiming they would all be there ).

…I was whole the time thinking of turn restrictions anyway. There are two types of them:

a) those which are inferrable from link-based restrictions (all restrictions in your example were such). I don’t even see any point in adding these as relations in the first place.

b) extra restrictions, ie., e.g. not allowed to turn left even though straight crossing of the street from right to left would be fine, etc.

To allow a fair compare of the number, it seems that the implicit restrictions would have to be deduced first.

By: Bobby Parikh

Bobby Parikh — Tue, 23 Feb 2010 22:35:44 +0000

Apmon-I’ll do what I can (legally and workload-wise) to share some of the stats later on deCarta’s devBlog.

ij and Mike-The 350K count includes only turn-restrictions (vehicle- and time-based included). What you’re referring to are link-based restrictions. For a model to be complete, it needs to have both. Imagine a four-way intersection between two roads–one being perfectly vertical and the other one perfectly horizontal. Let’s name the links with the four cardinal directions. If the South link has a PSV-only restriction, then the complete model would require the following:
1. A PSV-only restriction on the south link, and
2. No turn for vehicles other than PSV from the East and West links
3. No continue for vehicles other than PSV from the North link

The 350K count includes only turn-restrictions of types 2 and 3, not 1.

Sorry for the long explanation. I just wanted the answer to be complete.

Thanks for your comment Bobby. It was helpful. –Mike

By: ij

ij — Tue, 23 Feb 2010 12:51:07 +0000

“By comparison, the traditional map databases have over 350K turn restrictions in the US alone. 1300 vs 350K…0.37%”

Does 350k include restrictions which are implicit in OSM data such as not being allowed to access psv only ways or oneway streets in the opposite direction?

Thanks IJ – I don’t know the answer, perhaps Bobby Parikh will know. — Mike

By: Apmon

Apmon — Tue, 23 Feb 2010 10:55:07 +0000

Bobby – Those numbers are very interesting and roughly match to what I would have expected currently. I would agree, in my experience attribution for routing, such as maxspeed values and turn restrictions, is often still a bit of a problem. I think one of the reasons for this though is that these attributes are neither visualised on any of the much used maps (as it is not features to show on standard maps) nor were they supported by most routing engines that did exist for using OSM data. Therefore motivation of volunteers for including such attributes were fairly limited as they don’t get an “immediate reward”. So good visualisations (that are well known in the community) of routing attributes, like the restriction map you linked to (which unfortunately isn’t well known) or support in much used navigation apps like Skobbler or deCarta, can quickly change this. At least in areas where there is already a vibrant community, like Germany or the UK. The US, however is a bit of a different story. Due to large scale imports like TIGER, the data coverage appears much more complete than there is a community to support it yet. Unfortunately the TIGER quality is very poor for routing, no routing attribution at all and large connectivity problems. So it would be nice if you could do the comparison on routing attributes on Germany too, which is probably the “showcase piece” of OSM. Even there routing attribution is by no means “complete”, but from my own very limited experiments with comparing the routing of OSM data using GpsMid to that of a Navigon PNA around Karlsruhe, Germany, the routes provided were surprisingly similar. And that despite the fact that the routing algorithms of GpsMid (saying it as one of the programmers of GpsMid) are unlikely to be as good as those used in Navigon. So I think routing with OSM definitely has potential, if we can get the right tools out to expose those routing attributions to the community.

By: Valent Turkovic

Valent Turkovic — Tue, 23 Feb 2010 10:32:27 +0000

Great discussion!

There are quite a few OpenStreetMap online routing services, you can check out this list:
http://wiki.openstreetmap.org/wiki/Routing/online_routers

I know of a few iPhone apps that provide routing services with OSM data. I use OffMaps on iPhone and it works great in my hometown (Osijek, Croatia) in which I contributed most of the data. From what I have seen most iPhone developers use some online service to provide routing in their apps, they didn’t create their own routing engine. Most of them use OpenRouteService or Cloudmade as routing service.

If you compare Offmaps vs iGo on iPhone it is 2$ vs 90$ price vise, developers of iPhone apps have much lower barrier of entry in this segment because OSM privides the data and maps. Of-course iGO has some better features (like turn by turn navigation) but I don’t see that it has better maps.

The biggest issue for Turn By Turn (TbT) routing currently with OSM data is the lack of support for turn restrictions. None of online services supports turn restrictions!
Only software I found that supports turn restrictions, and therefor gives correct and legal routing info, is Gosmore (http://wiki.openstreetmap.org/wiki/Gosmore).

I started adding turn restrictions in my home town because to have accurate routing info in my home town but as soon as I realized that none of online services use turn restrictions data my enthusiasm was gone and I saw no point in adding new turn restrictions.

Please, please, please if you are working on any of one online routing services please implement turn restrictions ASAP, pretty please

Could gosmore be used for online routing service because it already supports turn restrictions?

As for liability – I got a Mio Map car navigation device that uses proprietary maps, after users turn it on for the first time they get an licence agreement that they must agree in order to use this device. Agreement clearly states than there is no liability, and that users can’t sue any company for anything and that users are to blame if anything happens while using this device.

Hi, Valent, thanks for your comments.

In regards to the liability issue, I am sure that all companies providing routing services are advised by their legal department to include a rejection of liablity notice. I suspect the “no-liability – It’s your fault” statement is about as strong as the agreement you sometimes must sign before you see a doctor, indicating that you will not sue if things do not work out.” When malpractice is involved, the agreement goes out the window, as it is considered non-enforceable by the plaintiff’s lawyer, and usually by the court.

If the PND manufacturer created a faulty routing engine (the functionality was broken and routed you the wrong way down one-way streets) or the company knowingly included data that did not support the functionality of the device (data that lacked turn restrictions), they (or the data provider) would be liable for negligence in most courts of law. Put another way, consumers should be able to reasonably assume that a device advertised as capable of routing them between destinations while their car is moving, should be able to expect that the database and functionality of the device are capable of performing the task by providing “legal” maneuvers when the car must change direction to navigate the path provided by the device. If the directions provided by the device are not “legal”, there is a liability question.

–Mike

By: Bobby Parikh

Bobby Parikh — Mon, 22 Feb 2010 20:14:48 +0000

First a quick intro and full disclosure: I manage the map data team at deCarta, a company that provides mapping/navigation/search platform and services for mobile and PND spaces. We have been experimenting with OpenStreetMap data for some time now. Some of you might remember our beta launch with OSM data last year. Our experience has been similar to a lot of other people who have commented here and elsewhere in creating a commercial offering using OpenStreetMap data.

I’d like to comment on routability of OSM data (as opposed to whether OSM should provide a service for routing). When it comes to display, search, and pedestrian/bike navigation, the level of attribution in OSM is good. You could caveat that claim with coverage inconsistency, but that’s not the main topic here. Vehicle turn-by-turn routing is another story. Traditionally deCarta has supported commercial map vendors, such as NAVTEQ and Tele Atlas, and we still do. So naturally we were interested in determining the type of TbT routing applications one could build using the OSM data. I know it might make some folks mad, but IMO OSM data is not ready for TbT routing yet. Here are some numbers: Turn restriction count is perhaps one of the most important features for determining routability of any dataset. There are about 12K turn restrictions in the OSM database worldwide (Source: http://osmdoc.com/en/tag/restriction/#values). Slightly over 5K of those are in Germany alone. The US has about 1,300. By comparison, the traditional map databases have over 350K turn restrictions in the US alone. 1300 vs 350K…0.37%. To have really satisfying TbT guidance, that number has to be a lot higher. You may disagree so let me know. Believe me, I’d love to be wrong on this, but I don’t think I am. So get out there and include those turn restrictions!

There are some challenges to capturing this data for OSM enthusiasts like us:
- How do we get non-experts to move beyond capturing POIs and such simpler features to this sort of advanced content?
- How do we get consistent modeling from users?

[Side note: For those who didn’t know, User:Langläufer has built a cool visual analyzer for restriction relationships — http://osm.virtuelle-loipe.de/restrictions/

I’ll posting our thoughts along these lines on our devBlog soon to coincide with our commercial product using OSM. We are trying to build a sort of readiness matrix. I’ll try to share that with the community.

Bobby – Thanks for the great insights. Your comparative statistics will be very helpful for anyone hoping to benchmark the readiness of OSM for route guidance. Thanks also for the links. Finally, your question on how to get consistent modeling from users is a crucial item. Another issue revolves around how you might “direct” the efforts of volunteers to resolve complex spatial data quality issues that “break” routes. — Mike

By: Matthias

Matthias — Sat, 20 Feb 2010 11:52:53 +0000

@Russell Nelson:

German user can’t put there data under PD. putting OSM into PD would mean that you have to delete all contributions from german users.

Hey, Russel, thanks for that clarification. –Mike

By: Russell Nelson

Russell Nelson — Thu, 18 Feb 2010 06:10:34 +0000

Oh, and for people laughing at “User Generated Cars”, there are a lot of people who would build their own cars. Trouble is that it’s very difficult to get permission to drive such a car on the roads. Typically, then, what people do is make a three-wheeler, which is legally a motorcycle. Since everyone knows that motorcyclists are insane, and at least halfway to death already, nobody really cares what kind of modifications you make to a motorcycle.

Thanks Russel. I think the comment that was made to me and recounted in the blog was one in which the person meant that the process would be like listening to a group of eyewitnesses report an event witnesed by the entire group – they all would have different opinions on what they saw. While I am sure you or I could build a car that might be pleasing, if we asked 2,000 people to build the same car, we might never see the end result or want to drive it if it was ever produced. — Mike

By: Marc Prioleau

Marc Prioleau — Thu, 18 Feb 2010 05:38:52 +0000

Good and necessary discussion. One thing to look forward too: In a few weeks Skobbler will launch an OSM based nav system for Germany, moving off NAVTEQ. Customer reaction (the ultimate determinate) will be interesting. Germany is a very sophisticated naviagtion market (having been at it longer than most other countries) and it is also the most complete OSM data set. So the real question will be how to measure customer reaction? Change in ranking in app store?

Hey Mark, thanks for the comment and the information about Skobbler.

Your measurement question is an intersting one that I had not thought about. I am not sure that App Store ranking would mean very much since it is so hard to evaluate applications on the basis of the information available when you buy them, although I suppose that the Skobbler app will get a lot of press and reviews that might help pre-sell buyers. A measure of how often the app was actually used might be more useful, but Skobbler may be the only one to know those stats. Certainly an interesting subject to ponder.

Are App Store rankings available by geographic region? If not, Skobbler will have a hard time ever equalling Doodle Jump. Thanks again. –Mike

By: Russell Nelson

Russell Nelson — Thu, 18 Feb 2010 05:35:16 +0000

I agree with you that the OSM licensing is a horrific mess. The only clear path forward is to put it all into the public domain, however a significant (and loud) portion of the OSM community is actively hostile to that idea. They think that a static dump of the data has value without them. They underestimate the value of continued participation in the OSM community. Several software vendors have tried to maintain Linux kernels separate from Linus’s. It was a nightmare. They gave it up. I’ve tried to maintain my own version of KA9Q’s NOS. It was a nightmare. OSM without the OSM community would be a nightmare.

I’ve tried, face to face, to convince Steve Coast that OSM should go public domain, but he’s 100% convinced that ($GEODATA_VENDOR) would take a copy and never contribute back.

Russel – thanks for the interesting comments. I am not sure I can see far enough into the future to understand how the licensing should play out, but I agree that what exists today is hindering growth and this is never desirable. I suspect that there are major differences of opinion within the OSM community and even within CloudMade. It will be interesting to see how the future rolls out for OSM and licensing. — Mike