|A site relation is used to group several objects together.|
|Tools for this tag|
A site relation is used to group several man-made objects which belong together but cannot be adequately described by an area/multipolygon. The group as a whole should have a common name and other characteristics.
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 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.
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=*/brand=* to group loosely coupled and/or widely distributed features - relations are not categories!
See the proposal page for more context and examples.
How to Map
To the characteristics all necessary tags are added:
Then the members are added without having to specify a role.
Members may include nodes or ways.
Sometimes other relations, especially multipolygon relations, have been added as members of a site relation. This can be difficult for database users to interpret, so it should be avoided where possible.
Site relations are typically not interpreted or used by database users such as map rendering or routing applications or any other software.
In many cases standard solutions, for example multipolygon relations are perfectly acceptable replacement.