[HOT] How newer mappers can help a lot with the validation process

Russell Deffner russell.deffner at hotosm.org
Thu Feb 11 18:29:08 UTC 2016

Hi all,


Validation is a ‘beast’ of a discussion that in my opinion has been addressed in two parts: teaching/training validators and technical changes in the Tasking Manager.  I for one completely support building a ‘white-list’ option (or otherwise the option to ‘appoint’ validators) into the TM; however don’t want to ‘spam’ the list too much, so I think this is the ‘most current’ and on-point issue in github: https://github.com/hotosm/osm-tasking-manager2/issues/599 


However, on the training side of things; we have built a ‘higher-level’ type of course for validation here: http://courses.hotosm.org/ but it is specific to HOT Disaster Mapping; there has been talk about a module for ‘general’ validation on LearnOSM, and Nick or someone closer involved with the Training Working Group can probably tell you more about that.


In either case, I think there is plenty of room for improvement.





From: Nick Allen [mailto:nick.allen.54 at gmail.com] 
Sent: Thursday, February 11, 2016 9:19 AM
To: john whelan
Cc: HOT at openstreetmap.org
Subject: Re: [HOT] How newer mappers can help a lot with the validation process


There is a wiki article at http://wiki.openstreetmap.org/wiki/OSM_Tasking_Manager/Validating_data

It needs updating. 

Nick (OSM=Tallguy)
my phone is responsible for any spelling mistakes!

On 11 Feb 2016 15:49, "john whelan" <jwhelan0112 at gmail.com> wrote:

In there somewhere in a wiki or some such where we can document validation, what works and why and what to look for?  Perhaps put down some sort of service level agreement ie after validation we are only looking for what is requested in the instructions and for a JOSM validotian to be run.  We expect 97% of settlements to be mapped type thing? That way people who wish to validate have something to feel confident about.

We need to get more people into validation.



Cheerio John


On 11 February 2016 at 09:56, Jo <winfixit at gmail.com> wrote:

If such a volunteer becomes more confident after a while, they shouldn't hesitate to actually validate the task, if all was mapped well and they didn't have to add/change much.

When I look at finished tiles, I start with the intention to validate it. If I have to do too much work on it, I will sometimes simply unlock once again, either leaving a note it's actually complete now.
If there is still more work than I have time for at that time, it's better to "invalidate", so another mapper knows where more work is needed.



2016-02-11 14:47 GMT+01:00 Blake Girardot <bgirardot at gmail.com>:

That is a good point John, if anyone does a second look to map in missing buildings in a "completed" task square you should leave a comment on the task square that says you looked over the completed task square and filled in all the missing buildings you could find.

For sure it is not a waste of time to review completed task squares, but I agree, it probably only needs one going over before validation.

In addition, this is a very helpful way for new mappers to become better mappers and contribute to an urgent priority project to get done well and fast.

Tiny task squares help, but stuff still gets missed and often we don't get the validation stage completed in time, no matter how important it is so an informal review makes a big difference if that is what a volunteer wants to do and can contribute.


On 2/11/2016 2:33 PM, john whelan wrote:

I'm not sure this is the best use of our very limited number of
mappers.  Just scanning a tile takes time, so the optimum use of mapper
time is to have them scan once when they map and have a validator scan once.

For a productivity point of view its better to have new mappers split
the tiles twice and map a tiny tile completely than have twenty of them
go over the same area.  From the same point of view its better to have
them map where we have good imagery than map where quote "You may have
to squint a bit".  Mapping whilst squinting takes more time to map the
same area than mapping where the imagery is good.  No matter where they
map it will be useful to someone if not a short term MSF or American Red
Cross project and to be honest if something like Ebola crops up having
fairly good mapping of existing highways and villages in place before
you start helps those projects in the field at least plan out what and

Cheerio John

On 10 February 2016 at 10:28, Blake Girardot <bgirardot at gmail.com

<mailto:bgirardot at gmail.com>> wrote:

    Hi all,

    I just want to mention, that new mappers can really help with the
    validation process by doing what they typically do: Map in roads and
    buildings but into "Completed" task squares.

    You do not need to mark a task square "Validated", but just
    reviewing the completed squares and filling in missing things or
    fixing up buildings that might not be mapped very well (squaring up
    the rectangular buildings :) is immensely helpful.

    I wrote a short OSM Diary entry that says basically the same thing:


    I just thought I would mention it because if you see projects on the
    Tasking Manager that look "done" just know you can always help a bit
    more by reviewing "Completed" task squares just to double check
    nothing was missed even if you do not feel experienced enough to
    "Validate" a task square.

    This is especially true for projects where we have made a call for
    more mappers on the email list or via twitter. Double and triple
    checks to make sure the mapping in the instructions is actually
    complete really helps in the process and gets the people on the
    ground the best data we can possible generate for them.


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