[Tagging] My "weirdly unnatural aversion to relations"

Paul Allen pla16021 at gmail.com
Tue Oct 2 16:01:33 UTC 2018

On Tue, Oct 2, 2018 at 4:39 PM Kevin Kenny <kevin.b.kenny at gmail.com> wrote:

> On Tue, Oct 2, 2018 at 11:15 AM Paul Allen <pla16021 at gmail.com> wrote:
> >> Why selecting buildings and tagging them to site relation is easier
> than selecting building and adding them to  a multipolygon realation?

> Are you labouring under the misapprehension that a multipolygon has to
> have a single outer ring?

Sorta.  As I read it the outer ring is a polygon.  That polygon might be
composed of several
different ways but together they form an continuous outline.  You appear to
be saying that I can have
several disconnected outer polygons.  Even if I can, it still doesn't
really work well for Edinburgh Uni.

>  That's a single multipolygon, and that's the approach that I'd use for
> the sprawling campus that
 you describe.

Then I described it badly, and/or you gave the map a very brief glance.  It
is NOT a sprawling
campus.  It is a city with isolated university buildings in it.  So you'd
walk along a public street
and encounter a house, a butcher occupying the ground floor of a house with
flats above,
a bookshop occupying all four floors of a house, a house that is now the
department of music,
a toy shop occupying the ground floor of a house, etc.  Repeat that many
times over.  It's NOT
a campus, it's a city with university buildings scattered here and there.
Well, one tiny part of
the city is a mini-campus to the extent that there are several university
buildings and no
non-university buildings in a small area, but otherwise it's isolated
university buildings in a
sea of non-university buildings.

Even if a multipolygon can have many disconnected outers, it seems I'd have
to make each university
building an outer.  And then there are no inners.  So even if it can be
done that way, it seems like
an abuse of the concept, which I thought was to be able to punch
exclusionary holes in areas.

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