[Osmf-talk] Mapping trees as buildings (was: Re: Alternative Strategic Plan)

[Andy Townsend]

On 15/05/2023 05:47, Emerson Rocha via osmf-talk wrote:
> Let me give a real world example. Weeks ago on unofficial 
> OpenStreetMap Telegram channel  (message 
> https://t.me/OpenStreetMapOrg/101372 ) a mapper from Colombia 
> complained that the buildings added in an area (near volcano Nevado 
> del Ruiz) was visited by local civil defense. The building=yes (added 
> by a human mapper, but geometry suggested 
> Microsoft/buildingFootprints) actually was a... tree. Guayacanes and 
> Yarumos to be more exact. He was pissed off on the chat, saying it 
> already complained in the past.


For the avoidance of doubt this was a mistake by a human mapper 
apparently from the same country (and with a bit of experience - 1000 
edits or so) using "RapiD 1.1.9".  It wasn't a new contributor to OSM 
attending a mapathon organised by an NGO abroad.  There appear to be no 
changeset comments on their changes suggesting that people have noticed 
problems with "trees as buildings" or similar.  If a complaint was made, 
it doesn't appear to have been made to this mapper.  Put bluntly, 
they're not going to know how problematic tools like "RapiD" can be 
unless someone tells them.  That's not to say that RapiD aren't really 
useful at finding missing buildings; just that they will also find some 
false positives too (a quick scan locally (UK) finds around 20 missing 
sheds and small agricultural buildings that no-one has bothered to add - 
and one that appears to be a bit of scrap metal, that isn't.

I'd suggest (and will suggest on Telegram) that a changeset comment 
helping them understand how to use tools such as this would be the best 
initial approach.

Best Regards,

Andy

(as usual writing here in a personal capacity, and apologies from 
dragging this thread even further from "strategic" things)