[HOT] Validators [was: COVID-19 For The Long Haul]

john whelan jwhelan0112 at gmail.com
Fri Apr 24 13:43:13 UTC 2020


What I found when validating HOT tasks was that if I provided feedback that
wasn't too negative on the task "ie the african highway wiki suggests that
this type of highway should be mapped thus: with a link and reference to
the wiki rather than you done it wrong" then the mapper would go on to do
far more tiles and do them correctly, but it had to be done very shortly
after the mapper had mapped.  So I'd sit on a project and immediately
validate the tiles as they were done.  It took considerable time and effort
on my part to do this.  I also noticed some validation was done by
inexperienced mappers who were invalidating tiles for correctly mapped
highways etc.  One that comes to mind was project manager who invalidated a
tile for a highway that had been correctly mapped in OSM before the project
started on the grounds that mapping highways was not part of the project.

However what I noticed as Jean-Marc has commented was that much of the
mapping problems were from mappers who hadn't completed the tile and their
feedback wasn't immediate.  Feedback sent to them was basically ignored 99%
of the time.

A couple of things happened.  The task manager changed and I could no
longer find the last tile mapped.  Response tails off over time.  Within
the hour 80% response, within a day 50% response, a week 2% response.
Validating a tile a week later meant the feedback didn't reach the mapper
immediately.  Second I'd no idea if the mapper had corrected their problems
later or not.  So the mapper might get half a dozen messages for tiles they
had mapped sometime ago and they had already changed their mapping
practices.  This is not positive feedback.

The second thing was the projects wanted buildings. I'd already noticed
that some buildings were being mapped two or three times.  Validating a
building? Well it takes me 2 or 3 mouse clicks to map one in JOSM with the
building tool, building=yes.  iD takes more clicks.  To correct an
incorrect building takes more effort than to map it correctly in the first
place.  Someone was kind enough to build me a script in JOSM that detects
duplicate buildings.  I'm not going to validate work when it takes longer
to validate than to do it correctly in the first place.

Then it gets interesting.  The JOSM validation tools have improved.  These
days I can grab about a tenth of an African country at a time.  It takes 16
gigs of memory and JOSM has to be set up correctly but it works.  The
duplicate building script now will detect duplicate buildings over one
tenth of the country not just a tiny tile.  JOSM validation and the todo
list are very powerful for picking up crossing highways, other errors and
doubtful tagging.

These days there are more automated approaches to picking up errors in
mapping.  Both Jean-Marc and myself fix multiple errors by HOT mappers.  I
must confess that if the error was made four years ago on a HOT project by
a mapper who has made four edits and the mapper hasn't mapped for four
years I might even correct the error without a changeset comment.

I worked with the training group to identify the most common errors, I
understand that training for project managers and validators has improved
and projects no longer ask new mappers for complex mapping.

I understand that validation can help new mappers and get projects
completed more quickly but I also understand it takes a lot of time and
effort on behalf of the validators to do it right.

Cheerio John



On Fri, 24 Apr 2020 at 07:06, Jean-Marc Liotier <jm at liotier.org> wrote:

> On 4/24/20 12:26 PM, Russell Deffner wrote:
> > Especially crucial are our Validators! With so many projects in so
> > many locations, it will be a monumental task to keep up on validation.
> > If you have the role, please leave the mapping to the newer
> > contributors and help us keep our quality up and give instructions to
> > mappers as soon as possible.
> What happens when tasks are invalidated ? In theory the errant
> contributor welcomes constructive feedback, fixes his contribution and
> mends his ways. How often does that happen in practice ? I almost (there
> are a few happy exceptions of growing contributors) never receive
> answers to changeset comments, so most often what was supposed to be
> validation ends up as mopping up after ephemeral contributors. I don't
> work with the tasking manager - my validation activities are driven by
> Osmose and OSMcha... Is the validation experience different with the
> tasking manager or is my experience representative of a problem ?
>
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