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I'm trying to tag a named grouping of small lakes with a group relation, and although relation:site seems to work, the wiki explicitly states it's only for "man-made objects". I see there's a relation:cluster option, but it's been in proposal for 5 years, and I haven't found a single consumer that renders it.

Is this a "hope it eventually renders someday" situation with relation:cluster, or is it acceptable to force a natural group of features into a 'site' relation - at least temporarily?

asked 30 Jan '20, 04:52

GregRetro's gravatar image

GregRetro
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accept rate: 50%


Why not a multipolygon first? Since they are small, even if they are multipolygons themselves there would not be significant difficulty on grouping their members into a new relation.

Disadvantage:

  1. Lost the hierarchy of individual areas in a group of area.
  2. Will create large multipolygons spanning a large area with many members in larger cases.

Advantage:

  1. Individual members can be easily referenced to be in both the individual area and group of areas.
  2. Easily understood, wide acceptance.

Is this a "hope it eventually renders someday" situation with relation:cluster

You might be surprised to find that most prominently the Great Lakes (https://www.openstreetmap.org/relation/1124369) too are tagged as the similar type=group. As long as they are in a relation, you can worry about it later.

the wiki explicitly states it's only for "man-made objects"

is it acceptable to force a natural group of features into a 'site' relation - at least temporarily?

That seems to be a misunderstanding and inadequancy on Wiki. A type=site is for grouping all objects in a single "site" (eg all facilities on an individual school campus). A type=cluster in theory is grouping multiple multipolygons (or any object) as one (eg complicated campus areas of a school spread over a city, or a collective bunch of rocks as illustrated in its proposal). I don't see any reason why a type=site can't be used to group natural features.

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answered 30 Jan '20, 07:05

Kovoschiz's gravatar image

Kovoschiz
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accept rate: 16%

edited 30 Jan '20, 07:06

I wouldn't use a multipolygon for the reasons you gave and also because you would lose the ability to individually tag the lakes.

I would go for the group or cluster relation. I don't see any significant difference between both so chose for yourself.

@Kovoschiz: A site relation is explictly not "for grouping all objects in a single "site" (eg all facilities on an individual school campus)". That can adequately be described by an area. Sites are used for scattered objects where the area inbetween does not belong to the objects

(30 Jan '20, 10:31) TZorn

I explicitly quotation-marked "site" for his reference. I also believe tags on member areas override the multipolygon tag.

(30 Jan '20, 16:11) Kovoschiz

@TZorn But WHY would you go for the group or cluster relation?

One of the individual lakes in the group is named, and a couple are seasonal, so yeah I don't want a multipolygon relation. Each element needs to be distinctive.

Here's the group - currently as a 'site' relation. www.openstreetmap.org/relation/10653013

Looks like site relations don't render much more frequently than clusters.

(30 Jan '20, 21:03) GregRetro

It's a gut thing. As you mentioned site is supposed to be used for man-made objects by the definition in the Wiki. Group and cluster are being used for natural objects.

I'm not sure it's really useful to have these three different yet very similar relation types. But that is another question beyond the scope of this help site.

(31 Jan '20, 10:51) TZorn
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question asked: 30 Jan '20, 04:52

question was seen: 1,171 times

last updated: 31 Jan '20, 10:51

NOTICE: help.openstreetmap.org is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum