I have found a routing error and don't know how to fix it.

asked 04 Apr '11, 07:31

Drifter2000's gravatar image

Drifter2000
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You have to be far more specific and provide further information in order to get help from someone.

Where do you have that routing error? (In some kind of application on the internet, in your GPS, etc.)

If possible post a link to where the problem occurs, or a screen dump.

Also describe what is the actual and the suspected results of the routing if not obvious from looking at the screen dump/link.

(04 Apr '11, 08:34) gnurk
1

I am using Open Street Maps on my Huawei Ideos Phone.The App is Navdroid. When navigating the area shown in the picture, the program sends me around the block as shown instead of straight ahead. The road changes from a normal two way street to a divided section and back to normal again. Will someone please fix this or explain how I can do it. Thanks Robert alt text

(06 Apr '11, 13:22) Drifter2000
1
(06 Apr '11, 14:07) gnurk

You are correct about the speed limit. It is 40 straight through and 50, I think, around the block. I will have a look tomorrow.

(06 Apr '11, 14:19) Drifter2000

Is "round the block" residential though? Isn't there a 50 km/h residential limit in Australia?

(06 Apr '11, 14:21) SomeoneElse ♦

Just for your info... there is a trend in Australia for local authorities to set permanent 40km/h speed limits in areas of heavy pedestrian activity (eg a busy "main street" where there are lots of shops, or a tourist strip), thus leading to some situations where higher-ranked roads have a lesser limit than nearby residential backstreets. Having said that, I think the routing algorithm still should preference the ranking of the road rather than purely speed limit.

(21 Nov '11, 18:37) wolftracker

Thanks for the 40 km/h info. I think that quite a lot of Australia (certainly a fair bit of WA) has had 50 km/h residential limits added "because that's what the limit usually is" rather than because anyone's been there and had a look. There's no "official" OSM router, so individual sites and services may choose to do it different ways - perhaps it might make sense to give users a choice "easiest route" vs "fastest route"?

(21 Nov '11, 22:46) SomeoneElse ♦
showing 5 of 7 show 2 more comments

Wow, you don't make it easy for people. A link to the area on the map (like this http://www.openstreetmap.org/?lat=-30.368927&lon=153.100585&zoom=18&layers=M) would be far more likely to get people to look at your problem. I only noticed the latlong when coming back to answer this question. Nor is this really the site for asking specific questions about the behaviour of individual apps or pieces of OSM data (once such problems are resolved, the question is unlikely to help others).

Interestingly there is a MapDust bug for this issue too: 177415(was that you?):.

I'll try and answer the interesting question: I have a problem with routing, how do I find out if its my app or OpenStreetMap data.

Firstly, its a good idea to check online routing sites such as those at OpenRouteService, Cloudmade, Yours etc. Not all cover the whole world. If you can see the same routing error on one of these services then chances are that its a genuine data problem.

Secondly, check to see if the data has been edited recently. Often routing providers are using data which is not as up-to-date as the main OSM Planet. It's important to not trouble people with problems with old data which as likely as not have been fixed. Unfortunately unless you edit an area its not always easy to determine the currency of routing data.

Thirdly check the junction which you think is wrong. check that all the ways actually connect to the junction (and also inspect one-ways and possible turn restrictions). The easiest way to do this is to use the Data layer (available on the (+) layer selector at the RHS of the screen on the main OSM site). Each way can be clicked on, and inspected in detail by clicking on "Detail" in the left-hand pane. This shows the browse/way page. Of course you can also inspect the data in the editor.

In this later step it is apparent that way 28988062 is not connected to Second Avenue at all (nor indeed is the other direction of First Avenue). I have fixed this in changeset 7784895 which you might like to look at to understand what was wrong.

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answered 06 Apr '11, 14:20

SK53's gravatar image

SK53 ♦
22.5k46229351
accept rate: 20%

edited 06 Apr '11, 14:31

4

Thanks for your quick action, I have a lot to learn, I discovered the fault with my gps and not by studying the map and was unaware I could send a link like that.I did do a quick search for help instructions and didn't find what I was looking for. Anyway thanks again .

(06 Apr '11, 14:35) Drifter2000
2

While navigating that road today, The routing was correct, so you have fixed it, thanks. Robert

(07 Apr '11, 06:48) Drifter2000

I suspect that you're talking about Sawtell, NSW, Australia, here.

I suspect that the reason for the routing is that First Avenue has a maximum speed set on it and a 40 km/h speed limit (see here), whereas the road parallel to that (this one) doesn't have an maximum speed indicated and is added as "highway = unclassified". It may be that Navdroid** thinks that speeds considerably in excess of 40 km/h are possible there and so the "round the block" route is quicker.

From looking at the Bing imagery in the area it looks like the parallel road might actually be better described as residential - I'd have a chat with the guy that mapped it. If there is a maximum speed indicated you could certainly add that, as you've done for First Avenue.

** I have never used Navdroid and so am only guessing about why it might be routing you this way.

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answered 06 Apr '11, 14:15

SomeoneElse's gravatar image

SomeoneElse ♦
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accept rate: 15%

2

No, I don't think that's the problem.

There is a nasty editing error in the crossing between 1st and 2nd Avenue.

The one-way road is overlapping and actually goes back under itself to the crossing, where it's not connected again, and then turns back again in the correct direction. I guess the routing software doesn't like things like that.

(06 Apr '11, 14:22) gnurk

Ah - well spotted (both by you and SK53).

(06 Apr '11, 14:28) SomeoneElse ♦
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question asked: 04 Apr '11, 07:31

question was seen: 5,622 times

last updated: 22 Nov '11, 16:46

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