|To attach other things to a node|
|Tools for this tag|
Node relations are used to attach other things (objects represented by the node relation) to nodes. In other words they create a virtual node at the same coordinate position as another, existing node. They can have only one member, a node. This datatype is useful when mapping several distinct objects at the same position, where all those objects shall be represented only by a node. With this relation you can have several point objects at the same spot without using multivalues or overlapping nodes.
These relations would typically have only one member.
You can either omit the role or add semantics by using roles like the following:
- attached_to to express that the feature is attached to the member (e.g. a pole)
- only_position to express that there is just a coincidence in position, not a different relationship
Usually you will add layer tags to the objects at the same position (node member and the relation itself) in order to define real world stacking.
Examples and Usecases
A usecase could be a pole with several traffic_sign=* attached to it (or also other poles where you would want to tag several distinct objects attached to them). Another usecase are trees with stuff attached to them, or a tower or a pole with different antennas attached. Even a waste basket with an excrement dispenser attached to the same support would be an example.