[Osmf-talk] Daylight Map Distribution (was: Re: Mapping trees as buildings)

[Andy Townsend]

On 16/05/2023 07:34, Christopher Beddow**** wrote:
> It seems the best approach to Emerson's concerns is to use Daylight 
> Map Distribution for any end user case because it removes errors and 
> graffiti from OpenStreetMap that the community does not miss.

I think that that downplays the contribution of Facebook** (who produce 
"Daylight Map") here.  I've not seen an example where "errors and 
graffiti" is removed from the "Daylight" map but left in OSM.  The 
nearest example I've seen are objects with no useful OSM tags (perhaps 
something with a "name" tag and nothing else), but they're not otherwise 
problematic.  Instead, my experience is that when Facebook people spot 
errors in OSM they fix them in OSM, just like other OSM mappers do.

Data consumers can choose to use Facebook's distribution from 2-6 weeks 
ago or OSM's from a couple of minutes ago - both will have "all the 
errors that have been spotted corrected" and both will have "some errors 
that haven't been spotted yet".  There will possibly be errors in 
Daylight that are fixed in OSM (and will therefore be fixed in the next 
Daylight distribution), but given the surprisingly small amount of OSM 
vandalism across the board any examples would be pretty hard to find***.

However, none of this is relevant to finding "trees mapped as buildings" 
by a mapper who thought that tools such as "Rapid" were better than they 
actually are at detecting things.  The only solution there is better 
training of mappers using Rapid and similar tools, and if problems are 
still occurring, then what training there currently is clearly isn't 
good enough yet.

Best Regards,

Andy

(from the DWG, but writing in an entirely personal capacity here)

** or whatever that company calls itself now - apologies for my lack of 
knowledge of how the various companies are arranged.

*** comparison of "Daylight" and "OSM" is pretty easy with e.g. Osmium - 
extract the area you want from each, dump both into "opl" format, remove 
the stuff that Facebook remove from OSM, and diff.

**** I'm guessing that this is the Christopher Beddow who a web search 
suggests is "Christopher Beddow - Geospatial Data Analyst - Meta", but 
presumably is writing in a personal capacity here.