[Talk-ca] Telenav mapping turn restrictions

Andrew Lester a-lester at shaw.ca
Thu Mar 30 05:14:11 UTC 2017

Hi Martijn, 

Thanks for your comments. Yes, I have commented on relevant changesets, though not every one I've come across. To be honest, there are far too many problematic changesets to start discussions on all of them. 

In using some QA tools to fix other problems, I've come across further instances of what could best be described as "sloppy" edits. For example, adjustments to road alignments to align them with Bing, but obviously with no attempt to properly align the imagery first. Bing is off by 15-20 metres in much of southern Vancouver Island outside of downtown Victoria, and I've seen some roads being moved that much out of place. Here's an example changeset: https://www.openstreetmap.org/changeset/46740353 (viewed with Achavi: https://overpass-api.de/achavi/?changeset=46740353#map=16). I see the source "Geobase roads" has been listed as being used as part of the edits, which actually reflects the correct alignment, but this seems to have been ignored in favour of the poorly-aligned Bing imagery. In addition, I've found a number of edits by Telenav members creating or moving highways such that they cross footways without an intersecting node, which indicates that the JOSM validator isn't being used before uploading the changes. 

In my opinion, based on what I'm seeing, the Telenav members don't have enough experience with the OSM ecosystem, tagging/mapping conventions, or editing tools to be making such widespread and prolific changes. I would strongly recommend that these members focus on mapping a local area that they can visit in person in order to gain experience with all aspects of actual on-the-ground mapping, and then later begin expanding to the rest of the country. Right now it seems like they're being thrown into the deep end with the hope that they'll just figure things out, and we're having to deal with the mess they're creating. I'm sure they mean well, but they just aren't qualified to be making the nationwide changes they are currently. I also strongly recommend that detailed proposals are brought to this community's attention before widespread tagging changes are made, such as the creation of tens of thousands of restrictions as detailed by Pierre. It would be good to confirm that the team is going to be making useful and correct changes before actually going ahead, just in case there's a better way of tagging/mapping things that the team wasn't aware of. 

As for the right-turn restrictions that I brought up earlier, I've posed the question of the legality of these right turns to a couple of sources (one that's pretty official) and am just waiting on a response. I hope to have one soon. This will only apply to BC, but it might help indicate whether the laws need to be investigated for other provinces as well. 


From: m at rtijn.org 
To: "talk-ca" <talk-ca at openstreetmap.org> 
Sent: Monday, March 27, 2017 9:08:26 AM 
Subject: Re: [Talk-ca] Telenav mapping turn restrictions 

Hi all, 

Thanks for your thoughtful commentary. 

First off, our mapping team’s only objective is to improve the map for us and for everyone. In doing this we always respect the work of local mappers, and follow community conventions. None of our edits are automated. There is a person using JOSM behind every changeset, so if you observe something untoward, please comment on the changeset so we can learn, discuss or undo if necessary. 

Some of our mapping team members are on this list and they can (and will) explain a bit more about how (and why) we add turn restrictions. 

I make a point to announce any new mapping projects we start to the local mailing lists (like I did when I started this thread). If there is anything we can do to be more open about our mapping projects I would be eager to discuss with you. 

Again, if you have specific concerns about edits any of our team members make in your local area, please! raise them in the changeset comments. It’s the single most effective way for us to learn how to to do better. Members of our mapping team are always identifiable by their usernames ending in _telenav. 


> On Mar 26, 2017, at 7:45 PM, Stewart C. Russell <scruss at gmail.com> wrote: 
> Hi Andrew: 
>> … I had already removed some of the 
>> right turn restrictions, but I can add them back in 
> Are the restrictions even necessary? If there are turn lanes present, 
> one should use them. I can see, however, that routing software might 
> send vehicles through the traffic lights if the turn lane were a longer 
> route. I wonder if Telenav are tagging to work around their routing 
> algorithms? 
>> There's still the matter of armchair mapping wiping out on-the-ground 
>> mapping. 
> Yes, this is troubling to me too. Have you left comments on the 
> changesets? Telenav's actions need to be brought out into the open. 
> I'm really not looking forward to seeing what all this algorithmic 
> mapping's going to do with Canada's logging roads ... 
> Stewart 
> _______________________________________________ 
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> Talk-ca at openstreetmap.org 
> https://lists.openstreetmap.org/listinfo/talk-ca 

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