So these tools are recursing down into relations which are members of
the higher-level relation, and then recursing down again? Is that not
configurable 

One concrete use case is "return the boundary relations for the
constituent parts of a given boundary relation", for example "all the
district councils in Kent" or "all the counties in Wales". That won't be
reliable if rectangular bounding boxes are used, or centroids as in
"where the centroid of the lower level relation is within the polygon of
the higher level relation". The OSM boundaries in the UK are of various
vintages, and are not all present (especially at the lowest levels,
civil parishes and community councils). I am working as hard as I can on
getting the data complete and up-to-date but it is an enormous job, with
over 12,000 administrative entities. That's why the quick and simple
feedback that this parent-child link gives is so important to me. The UK
also has a number of anomalies, such as an English authority covering
some territorial waters of Wales, a ceremonial county split between two
administrative counties, and missing layers such as Berkshire where the
county still exists but the council has been abolished. I have written
some special-purpose tooling to allow me to track progress and detect
(possible) errors. Without the "subarea" link, I fear I could no longer
work with the XML from the API or regional downloads without installing
a full software stack including PostGIS etc. Did I mention I refer to
the history of the objects as well? 

//colin 

On 2015-11-27 11:05, Martin Koppenhoefer wrote: 

> 2015-11-27 10:54 GMT+01:00 Colin Smale <colin.sm...@xs4all.nl>:
> 
>> Can you describe some *real problems* the use of "subarea" causes? Can you 
>> provide any *workable* alternative for the parties which DO support its use? 
>> I thought that the "O" stood for "Open". Mappers who don't know about it 
>> just carry on.
> 
> the real problem (for me and other mappers in the Italian community) are 
> people coming by and adding all regions of Italy as subregions into the 
> country boundaries, continueing adding all municipalities (or better most of 
> them) into the region relations. This results in many common tools selecting 
> all contained municipalities when selecting the country and the geometry it 
> depends on (members). In Italy we don't have the problem of unprecise 
> sub-boundaries which are not integrated in the upper boundaries. It makes 
> editing of these relations much more complicated for everyone if all 
> sub-boundaries/entities which are not needed for the boundary of the country, 
> are included as well.
> 
> Workable alternatives for which problem do you require? Is it that subareas 
> are not completely spatially contained in the parent area in OSM but are in 
> the real world? Then the solution is to fix these sub-boundaries. If instead 
> the subareas aren't completely contained in the parent area in the real 
> world, then I'd question the subarea-role for these cases (they are not 
> subareas).
> 
> Cheers, 
> Martin
 
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