[Tagging] how to map simple buildings

Tobias Knerr osm at tobias-knerr.de
Sat Mar 4 20:21:49 UTC 2017


On 04.03.2017 18:05, "Christian Müller" wrote:
> Thanks for the examples and conclusion given.  This is a strong reason to
> demand its usage in wiki docs and IMO we should even suggest their usage
> generally, regardless of the construction site's complexity.

Situations complex enough to require type=building relations are 
possible, sure. As Martin observed, though, those are exceptional cases. 
The existence of a small proportion of buildings that call for relations 
does not feel like a good reason to demand relations for every single 3D 
building.

 > Even when neither multi-layered nor nested buildings exist, they may aid
 > in data validation and plausibility checks.

If I tried to find the most common mapping errors with 3D buildings, I 
would probably look for some of the following situations:

* Building parts that cannot be unambiguously matched with a building 
outline.
* Buildings that aren't fully covered in building parts.
* Floating building parts that don't touch the rest of the building.

And probably a few more. None of these requires relations.

> Yet they may ease maintenance
> work for oneself and other mappers, since they usually convey an overview
> of all the parts present. But of course it depends on mapping workflow if
> this is true to a particular mapper.

While there are mappers who love using relations as part of their 
workflow, the relatively low usage numbers of the building relation (and 
other optional relations) strongly suggest that this preference is not 
shared by the majority of mappers.



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