[Tagging] Overlapping lakes

[Frederik Ramm]

Hi,

On 2/12/21 14:50, Richard Fairhurst wrote:
> How should this be mapped?

Here's a data point for the discussion:

In Copenhagen there's a group of five inner-city lakes known as (not
joking) "The Lakes" (https://da.wikipedia.org/wiki/S%C3%B8erne).

The geometry of the five lake outlines is mapped by one closed way each:

https://www.openstreetmap.org/way/3098222 (no tags)
https://www.openstreetmap.org/way/3098223 (no tags)
https://www.openstreetmap.org/way/3098754 (no tags)
https://www.openstreetmap.org/way/3098755 (no tags)
https://www.openstreetmap.org/way/25466125 (natural=water)

They are combined in a type=multipolygon relation with a
wikidata/wikipedia tag but no other tags:

https://www.openstreetmap.org/relation/6244787

Two of them form the "Sankt Jørgens Sø" relation (type=multipolygon
natural=water): https://www.openstreetmap.org/relation/6244786

Two others form the "Sortedams Sø" relation (type=multipolygon
natural=water): https://www.openstreetmap.org/relation/4637688

The fifth is "Peblinge Sø" and carries its own natural=water tag.

This whole structure is carefully built so that nothing is duplicated
(the big "Søerne" relation does not have a natural=water tag, it is a
featureless multipolygon). Its main purpose seems to be to give an
anchor to the Wikidata/Wikipedia article.

It all seems well thought-out, but at the same time asking for trouble
due to its complexity.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"