[OSM-talk] Help with way forward with Grab

John Whelan jwhelan0112 at gmail.com
Mon Jan 7 16:30:49 UTC 2019


It's a difficult call.  I do a fair amount of armchair mapping and in 
general I use the lowest classification of highways that looks 
reasonable when I add a highway,if it should be higher then I leave the 
change to the locals.  In general I do not delete or change tagging 
except when buildings have been duplicated when I'll delete the 
duplicates if I'm feeling nice.

Having said that when I see two small villages joined by what looks like 
an unconnected 2 km narrow dirt highway tagged as a motorway or primary 
highway I will change the tag to unclassified.

Many of the problems come down to training.  HOT has some very 
reasonable training guides.

At the end of the day the company commissioning the work want accurate 
maps so the goals are the same.   I'd suggest a team approach, simpler 
tasks are given to new mappers, more complex tasks such as changing tags 
or guessing if two highways are connected be given to ones with more 
experience.

Occasionally I'll see something that looks odd.  If it was done three 
years ago by  someone who hasn't mapped in three years and only made 
four edits I'll probably correct it. If it was made by an active mapper 
with a few thousand changesets to their name we'll have a discussion.  
If it was mapped by Fredrick Ramm I might even leave it untouched.

If it says "I love Elsie" with a heart shape I have been known to delete 
it without reference to the mapper.

Cheerio John

Mishari Muqbil wrote on 2019-01-07 9:23 AM:
> Hi Everyone,
>
> Some people from the Thai mapping community are meeting Ajay, the 
> mapping lead from Grab to discuss the quality issues we've been having 
> with their mappers but before we do this I wanted input from the wider 
> community. For those who are unaware, Grab has commissioned another 
> entity, Global Logic, to do the edits.
>
> I've made some example of quality issues here: 
> https://wiki.openstreetmap.org/wiki/Grab/Issues I think I need more 
> help to categorize the problems and propose remedies for them 
> especially in the context of directed mapping teams. There were also 
> more issues documented in this thread 
> https://forum.openstreetmap.org/viewtopic.php?id=6407 but I haven't 
> sorted through all of them. This process would at least take the focus 
> away from individual problems and allow us to come up with a strategy 
> for dealing with classes of problem instead.
>
> From what I can tell, these are the broad classes of issues:
> 1. Connecting roads where no connection exists - ie. making guesses 
> where there are buildings or tree covers blocking satellite imagery.
> 2. Incorrect Tagging - i.e. residential roads in areas marked as parks
> 3. Not using up to date satellite imagery and overriding recent 
> changes made by local mappers
> 4. Changing existing tags - ie. secondary_link to primary etc. 
> overriding local mappers discretion.
> 5. Micro-alignment using satellite imagery
>
> What I would like help with is this:
>
> 1. What's a fair expectation from such a mapping team? On one hand 
> there's the potential to add much geometry to the project, on the 
> other hand any bad data has an outsized effect on utility and 
> perceived quality. What's the sweet spot? Sadly Bicycle routing in the 
> Grab mapped areas in Bangkok using Brouter.de is now unreliable 
> because service roads have been added without information about access 
> permission or barrier and in other cases ways have been connected 
> where no connection exists.
>
> 2. Thailand's mapping community is small and it would be impossible 
> for us to go through all 7,000 edits made and set it right. I've 
> identified at least one of the issues (1-3) in roughly 1 out of 4 
> changesets made by Grab/Global Logic in my neighborhood in Central 
> Bangkok and I would be unable to give feedback on any issues outside 
> of this zone, likely the same with other mappers.
> 2.1 Should we just ignore the errors, slowly fix the errors, or demand 
> Grab fixes it somehow? Can we take lessons from any other projects, 
> say TIGER imports?
> 2.2 What would even constitute as a fix by Grab? Should we ask them to 
> do something like fixme=verify_on_ground on the new entries so that it 
> can be ignored by the routing until verified? At least it will make 
> the map usable again. Alternatively we identify the sweet spot in (1) 
> and ask Grab to redo their edits to comply.
>
> 3. It's been difficult to agree with the mapping team on a standard. 
> They did make some statements in this post 
> <https://forum.openstreetmap.org/viewtopic.php?pid=720203#p720203> 
> which seems to highlight a difference of understanding between the 
> community and the mapping team.
> 3.1 There doesn't seem to be a way in to enforce a commitment. 
> Hypothetically if they said "we do QC" then we continue to uncover 
> errors or “we don’t retag” when clearly this is happening, we can’t 
> stop them.
> 3.2 Maybe there needs to be a way of assessing mapping activities so 
> new organized mappers know what would qualify as a high quality 
> contribution.
>
> 4. The directed editing policy 
> <https://wiki.osmfoundation.org/wiki/Directed_Editing_Policy> page 
> gives some good guidance but I think some best practices are required, 
> complete with example workflow and KPIs. Maybe this can be related to 
> scale, the bigger the scale of edits the stricter the quality and the 
> more transparency required. There can also be a difference between 
> mapped vs unmapped areas. Has anyone published any such material for 
> their own mapping projects that we can propose to Grab?
>
> 5. I brainstormed some ideas with varying levels of feasibility in 
> case it can be built upon by others:
>
>   * Local Grab mapping team oversee remote work and are responsible
>     for the remote mapper's edits.
>   * Mappers are put in small teams with team leaders being personally
>     responsible for quality.
>   * Transparency about quality issues, affected changesets, causes and
>     remedies ie. everything on a public issue tracker.
>   * Global Logic brings experienced OSMers to their production room
>   * Global Logic makes their process open so that the community can
>     identify weaknesses and points of errors
>   * Bounty: Grab deducts US$5 from Global Logic's remuneration and
>     gives it as ride credit to local contributors who spot a bug. This
>     would align incentives :-)
>   * Fork the map, copy it and make changes on their own servers, allow
>     the community to pull in whatever changes we want into the main map.
>
> Thanks in advance.
>
> Best regards
> Mishari Muqbil
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