Relations/Proposed/Site

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Site Relation
Status: Draft (under way)
Proposed by: Jojo4u
Tagging: type=site
Applies to: relation
Definition: A way to group features which belong together but cannot be adequately described by an area/multipolygon.
Drafted on: 2008-01-02
RFC start: 2010-02-01

Proposal

A way to group features (represented by nodes/ways/areas/relations) which belong together but cannot be adequately described by an area/multipolygon. A common example are dispersed power plants like wind, tidal and photovoltaic power plants which are mapped as nodes. This relation is understood to group man-made objects. For groups of natural objects which share the same name see proposed relation Cluster.

However, this relation is not to be used in cases where the elements are inside one or more areas where the perimeter can be tagged with an appropriate area area tag. For example the tag amenity=school describes the perimeter of the school grounds, for schools with multiple sites the multipolygon relation should be used. For an university with buildings scattered throughout the city a multipolygon amenity=university with the buildings as role outer should be used.


Note also that it is not useful to create relation that has a perimeter of area (for example camp site) and includes objects within that area as elements. Each object in OSM has already a location and it is not necessary to duplicate this information.

The features should have a close geographic relationship, usually within the same town. For example do not use this relation to group all restaurants of a fast-food chain. Use a a combination of name=*/operator=*/network=* to group loosely coupled and/or widely distributed features - relations are not categories!

Reasons for Area/Multipolygon Insufficiency

Tagging

Key Value notes statistics
type site
* * The main tag - whatever feature the site relation describes. E.g. amenity=university, site=parking, power=plant.
name * The name of the feature
site * Legacy tag describing the type of the site, better use the full tag (main tag). Existing usage may continue. Might also be used for new sites if no suitable full tag exists.

Members

Way or Node Role Recurrence? Discussion
node way area relation none zero or more Anything you want to tag as part of the site. e.g. buildings, parking entrances, power generators, (looking for more examples).
closed way perimeter zero or one see sub-proposal Proposed_features/Site_Perimeter
entrance zero or more Node(s) on the perimeter defining the entrances to the site. Removed since perimeter around whole site is contradicting this proposal

Examples

Feature Tag Statistics Example
Mine where only entrances are mapped type=site
+ man_made=mine
relation Ofenkaulen

Documented Uses

Feature Tag Statistics Example
Dispersed facilities power plants like wind, tidal and photovoltaic power plants. type=site
+ power=plant
up to 436 (2015-08) relation Høg-Jæren Energipark
Parking sites - useful for cases where parking entrances are mapped but parking area is not yet mapped. Once parking is mapped as an area with service roads marked site relation is no longer useful and may be safely deleted. type=site
+ site=parking
relation Parkhaus Liederhalle/Bosch-Areal
Heritage site
Historical Objects Map
type=site
+ heritage=*
at most ~1000 (2015-08) relation Weißenhofsiedlung
Historic site
Historical Objects Map
type=site
+ historic=*
at most ~3800 (2015-08) relation Festung Torgau
French survey point site (IGN import) type=site
+ site=geodesic
relation Le Bélieu I

Documented Uses (incompatible with current definition)

Feature Tag Problem Statistics Example
UK NaPTAN type=site
+ site=stop_area
partial import, should migrate to public_transport=stop_area relation Bridgtown. Watling Street. Cross Street
South Africa shopping areas type=site
+ site=mall
most representable as area no known cases of useful relations
Piste site (rejected) type=site
+ site=piste
tagging as area preferred by some, issue open relation Meiringen - Hasliberg
Camp site (proposed) type=site
+ site=camp_site
most representable as area no known cases of useful relations
Playground site (rarely used, no known cases where it is not duplicating info inherently stored by OSM databse) type=site
+ site=playground
no known cases where it is useful no known cases of useful relations

Statistics

2015-08: 135 392 total, 48 476 NAPTAN, 72 586 IGN, 14 330 other uses.
2016-04: 136 829 total, 48 103 NAPTAN, 72 578 IGN, 16 148 other uses.

Rendering

Note that rendering support may be hard to implement. OpenInfraMap renders power plants tagged with type=site.

See Also

Proposed_features/Site_Perimeter sub-proposal bringing areas to the relation.

Discussion

Discussion on the Talk page.

"Feature Proposal - RFC - Site Relation" from 2011 on the tagging mailing list.
"Feature Proposal - RFC - Site Relation" from 2015.

Origins

This proposal was created by User:Milliams with significant editioral work by User:Joshdoe. In 2015/2016 User:Jojo4u developed the proposal further towards the principle only when not representable as area. A version of the original proposal from 2013 can be found here.