[HOT] Buildings and HOT's reputation in OSM

john whelan jwhelan0112 at gmail.com
Sat Dec 9 19:59:53 UTC 2017

Recently there has been some discussion of HOT's input into OpenStreetMap
in the OSMF mailing list.

Perhaps one of the problem areas is mapping that is less than ideal.

Basically HOT mainly maps highways, landuse=residential and buildings.

These shouldn't be difficult to map correctly.

Buildings appear to be the most problematic.

I think we need to think about why we are mapping them.  Is node good
enough?  There would be less room for mistakes.

If we need outlines and there good reasons why an outline is more valuable
than a node then we need to define what is acceptable.  Or do we even
care?  and its the do we even care part that is perceived to be the case by
some within OSM and that perception is something we should care about.

>From a validation point of view does it matter if the building is not
square?  Is it acceptable to square a building even though we know this
will introduce an element of approximation or error.

What should be done with a building=yes that covers more than one
building?  Do we expect the validator to map each building or just
invalidate the tile?

What should be done when the building mapped is more than 50% larger than
the image?  Invalidate the tile?

We are still mapping buildings twice.  I suspect some mappers are not
uploading within two hours.  Getting mappers to upload every 30 minutes max
would go a long way to reduce this, extending the tile lock to four hours
would almost certainly eliminate it.  Recently on high priority project
I've seen in the order of a hundred buildings double mapped.  They have
been done within the last two weeks so it is an ongoing problem. There is a
new tool that detects these so they aren't the problem they once were but
someone has to run the tool.

If HOT could support a few more projects that were from the community on
the ground rather than the "We are the professionals we know what is best"
which appears to be perceived sometimes from the number of projects for the
RED Cross or other northern hemisphere charities that might also help the
reputation and relationship.

So two points here on one message first is can HOT's reputation be repaired
and I suspect that is longer term problem that will take time and a lot of
effort rather than a PR job.

Second would someone care to comment on what is acceptable mapping for a
building and what guidelines can we give to validators?

Thanks John
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