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

Paweł Paprota ppawel at fastmail.fm
Tue Jul 31 08:31:53 BST 2012

On Mon, Jul 30, 2012, at 23:55, Frederik Ramm wrote:
> No. We only create relations when the ref tag is not sufficient. We 
> don't recommend that relations be created for roads otherwise, and 
> anyone doing anything with the data should not expect relations to be
> there.

How would you define "sufficient" then? Is copying same "ref" value to
thousands of ways in major national (or even long regional) roads a good
use case for "ref"? I think this "freedom of choice" and lack of clear
guidelines is an illusion in this case since it creates inconsistency.

Someone said earlier that OSM is not a technical project but a "social"
one. Well I would agree BUT for the reasons that Petr Morávek describes
very well in this thread there needs to be a minimal level of consensus
for tagging stemming from technical reasons - like this situation here
for major roads.

And it is easy to achieve that - recommend that "the target is that we
want to have well-maintained relations for major roads in Europe", then
motivate people with reporting tools and it works - Poland now is headed
for a nicely cleaned up road network because people are trying to get
the report "all green" and also are enjoying that they are doing
meaningful work by remapping/fixing major roads which as it turned out
from reporting were in not-so-good state.

I'm not sure why some people get very defensive when someone suggests
some basic (and reasonable - I think) guidelines in order to improve the
data quality. Of course communities can go on and maintain stuff their
way but going for unified approach within EU for example could foster
collaboration between countries - like now German people are actively
fixing road network in Poland and using the reports. I see this going to
the next level when mappers from EU countries start to build relations
for Euro routes and look at the data in different countries. How is this
bad? The recommendation of using relations in this case is just to kick
off the whole thing and define some base line for collaboration - not
because I desperately am itching for fixing some technical design
problem in OSM.

> A world-wide unified approach is difficult and does not have only 
> advantages; being forced to use the same approach in Chile and in China 
> might not be the best way to model reality. And since it only rarely 
> happens that someone travels from China to Chile using the same software 
> - maybe a unified approach isn't even required.

World-wide would indeed be hard - but EU (see above) for starters could
be interesting, no?


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