[Tagging] network tag on route relations

[Robert Skedgell]

On 12/07/2020 15:48, Mike Thompson wrote:
> Hello,
> 
> According to the wiki[0], it seems that the network tag has different
> meanings and possible values based upon if it is applied to a route
> relation where route=road vs. route=bicycle/mtb/foot/etc.
> 
> If I am understanding this correctly, when route=road, network= the
> specific network that the road is part of, for example, a US Interstate
> would be US:I[2]
> 
> For bicycle/mtb/foot etc. it seems that the network tag indicates the
> scope of the network, for example a nationwide network cycling network
> would network=ncn[1]
> 
> 1) Why can't the network tag have consistent meaning across all route
> types? For a mapper, as well as a data user, this is confusing.  
> 2) The scope of a cycling/walking/etc. network should be evident from
> the geographic extent of its members, so isn't network=icn/ncn/etc.
> redundant? In any event, if the specific network is specified, it will,
> in most cases, also indicate the general scope.  
How do you know the scope of a network if there is no tag to indicate
that member routes belong to it?

The very short NCN route 425 in south-east London is network=ncn because
it's a Sustrans route. THe scope of the route is very local, but the
scope of the network is national. Without the network tag, how would a
renderer or router determine whether it was an ncn, rcn or lcn? All
three exist in Greater London.
https://www.openstreetmap.org/relation/4247567


> Mike
> 
> [0] https://wiki.openstreetmap.org/wiki/Key:network
> [1]
> https://wiki.openstreetmap.org/wiki/Key:network#Bicycle.2C_hiking_and_other_recreational_routes
> [2]https://wiki.openstreetmap.org/wiki/Key:network#Hierarchical_format