[Tagging] Data redundancy with "ref" tag on ways vs relations

Jo winfixit at gmail.com
Mon Jul 30 22:19:22 BST 2012

> there are different types of errors and you focus on one only. I am not
> going to argue with examples or explanations. If you don't want to see it
> you won't see it.

I'll try to give another example, which may or may not help Pawel to see
what you mean:

I'm gathering information about bus routes. When a mapper is in front of a
bus stop, they can easily take note of all the lines serving this bus stop
and adding this information to route_ref.

Now I come along and create a route for the itinerary of one of the routes.
It helps me that I can find all the bus stops served by this line with a
regular expression.

Should all the route_refs now be removed once the route relation is
created? I don't think so, as they can easily be used to help verify
(programmatically like you did) that my route relations remain correct. One
could argue that this creates redundancy of data in the database, but this
redundancy is what makes data validation possible.

For giggles I downloaded all ways with ref=N2 with an overpass query (

out meta;

I should have added a bbox there to limit it to Belgium, but most of my
Overpass queries are more specific.

I found that we don't seem to be using relations for N-roads, but we do for
A-roads and E-roads (i.e. all the motorways). I also found that here in
Belgium those roads seem to be 'interrupted' through the city centers,
which would complicate checking them for continuity.

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