[Tagging] Admin Boundary admin_centre or label roles

[Jeroen Hoek]

On 01-10-2021 08:42, tguen--- via Tagging wrote:
> As I said before, if using label nodes as a hint for renderers truly is
> "bad and unwanted", then place nodes have no reason to coexist with
> boundary relations. Would you object to me deleting them?

You would instantly break many OpenStreetMap styles that rely on those
for rendering places from city down to neighbourhood. The status quo
appears to be that renderers need not interpret boundary relations
because a node is expected to be present as well. Moving away from that
to a system of either a node (in case the boundaries are not known) or a
boundary relation would in my opinion need broad consensus and a longer
term planning for renderers and underlying dependencies to be able to
update their implementations, because it would break the map in a
significant way (i.e., many place names disappearing).

It would also come down to deciding unilaterally that mappers being able
to influence the location of place labels is 'bad and unwanted'. This is
a matter of opinion, and while instructing the renderer directly is
usually not desirable, in some cases the alternative is not good enough
for a good map.

In an ideal world all boundary defined places are roughly circular, and
the middle of those is where anyone would expect its name to show up.

In reality, places have all sorts of weirdly shaped boundaries, and what
counts as 'the middle' for people is often a long way from the centroid
or any other mathematically derived centre. The current generation of
renderers cannot always place the labels in a suitable location based
solely on the boundary data.

In some other cases, the position of the label is also strongly
influenced by cultural factors. For mediaeval cities there is often an
old city centre that is in the minds of the populace 'the middle' where
such a label should appear at a low zoom level.

There a lot of factors to weigh for automatic label placement, and with
really good algorithms perhaps we could do justice to 99% of the cases
some day, but we're not there yet. In the mean time, having the label
node (with its label role in a boundary relation) seems like a very
sensible compromise. We're mapping for the benefit of humans as well
after all.

Jeroen Hoek

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