On 10/02/2018 20:52, john whelan wrote:
My personal reaction is this is frightening.
Already we have buildings mapped twice and unless the import is done
very very carefully I can see problems ahead.
This sort of thing has been tried before, with varying degrees of
success. Facebook tried to import some "roads" in Egypt (for a bit of
background see
https://www.openstreetmap.org/changeset/41096427#map=11/29.9540/31.0432
and https://www.openstreetmap.org/user/Chetan_Gowda/diary/39149 , and
links from those). Much of it needed to be reverted, because quite a
lot of "straight lines with colour differences" got interpreted as
"residential roads" when they were actually walls or drainage ditches.
The import in Thailand is discussed at
https://forum.openstreetmap.org/viewtopic.php?id=57942 , and there are
still ongoing issues with the quality there (such as
https://forum.openstreetmap.org/viewtopic.php?pid=684197#p684197 ). That
last one https://www.openstreetmap.org/way/556830183 is a particularly
interesting case because I suspect that many "experienced armchair
mappers" would make the same mistake there - thinking that the road
continues and not noticing the fence (visible on only 1 of the 3
available OSM imagery sources). I suspect that 99% of relatively
inexperienced mapathon participants would make the same mistake.
The jury's still out on the overall benefits of the Facebook Thailand
work - see e.g.
https://forum.openstreetmap.org/viewtopic.php?pid=684270#p684270 in that
thread, but it's definitely worth mentioning some of the things that
they got right there (in some cases, only after a bit of prodding):
* Imported data clearly marked so that data consumers can process it
differently if they wish, like JOSM does with raw TIGER data.
* Engage in a dialogue with the local community in the local
community's forum.
* Mappers with OSM user pages that explain who they're working for and
who (at least sometimes) do respond to changeset discussion comments.
However, before we get carried away it's worth remembering that none of
the examples on
https://www.openstreetmap.org/user/jremillard/diary/43294 are actually
imports - they're things like QA and targetted Maproulette tasks. It's
now up to the community to suggest use cases. If someone tries an
undiscussed import without following the policy they should rightly be
stopped as Facebook were in Egypt.
Best Regards,
Andy (from the DWG, but writing in a personal capacity)
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