|Used to describe networks of various kinds.|
|Status: in use|
|Tools for this tag|
The tag type=network is used in some places to tag relations which represent a "network". Most commonly this has been used to map bicycling and walking "node networks" in the Low Countries of Europe, and public transport systems in some cities.
Use of this relation sometimes violates the principle that relations are not meant to model categories like "all tram stops in Frankfurt".
- Network relations group their member regardless of a certain key or feature, as OpenStreetMap does not feature static IDs, the creation of network relations creates a "real" group.
- Each member can be described with a certain role, which is especially useful for network relations.
- Some network-relations may become huge as they represent huge network, this may become an issue.
- Especially new mappers repeatedly did not understand that/how they had to add parts of the network to the relation. Therefore, this was not always done properly and required additional maintenance.
Alternative to network relations
The use of the tag network=<xyz> for all members of a network is the most common alternative. The drawback is that the value of the network is often not unique and the network=*-tag is used differently for bicycle and hiking routes.
Outdoor sport networks
The concept of network-relations is used for node networks in particular. This enables grouping of nodes.
Public transportation networks
Network-relations were sometimes used in the context of a common fare system, a certain type of transportation and the (subsidized) concessions to operate a number of lines. Unfortunately, this usage violated the principle that "relations are not categories".
Former Netherlands approach
Network relations were used to mark the membership of a route to a public transport concession. This was motivated by the ease of maintenance in the light of constant changes in concession ownership. However, this has mostly been abandoned. Now almost all uses of this tag in the Netherlands are for cycling node networks (see Proposed_features/Node_Networks)
The idea of network-relations for concessions or fare systems (German: Verkehrsverbunde) was doomed on the mailing list as they change regularly and have no relevance for the users. The current situation seems to be that everything is mapped in the route=* or route_master=* relations and network relations are abandoned and ignored (examples: missing underground line 4, with note=teilen, teilen, teilen, German for
divide, divide, divide).