[OSM-talk] Maximum recommended length of ways tagged with layer

Richard Z. ricoz.osm at gmail.com
Sat Mar 22 10:01:46 UTC 2014

On Fri, Mar 21, 2014 at 05:05:21PM -0500, Paul Johnson wrote:
> On Mar 21, 2014 4:59 PM, "Richard Z." <ricoz.osm at gmail.com> wrote:
> > Example of a problem this should catch: I have seen cases where someone
> > wanted to tag a simple bridge with layer and added the layer to the wrong
> > segment - tagging a hundred or more miles of road accidentally, possibly
> > affecting crossings far away for an area not downloaded. The validator
> will
> > not detect it and in most cases the renderer will work around this bug
> very
> > well so it is only discovered by accident in most cases.
> > This is not limited to layer, I have seen the same problem with culverts
> and
> > bridges.
> This seems like something a validator should be able to catch without
> overly complicating how levels work.

I am not trying to complicate how layers work right now but trying to codify
how they already work in >99% of cases in easy to follow rules that could be
utilised by validators.

Yes, the validator should be able to catch such situations. Just how? 
It doesn't right now. I see some possible approaches:
* warn user if tagging excessively long ways with "layer". Here the problem
  is to judge what is excessively long.
* warn user if applying layer to a way that exceeds the size of downloaded area
  because in this situation the validator is unable to do even the basic checks.
* warn user if applying layer to a way without tunnel/bridge/covered/indoor or
  similar tags.

There is more than just JOSM and all should follow the same rules so ideally 
this rules would be nicely documented in the wiki.

> > What kind of underground areas are that in Kansas, do you have a pointer?
> I'm not exactly sure where exactly it is, but there's apparently a pretty
> extensive underground industrial and office district entirely underground
> complete with drivable underground streets in KCK thanks to repurposing an
> old mine.

interesting, I will have a look when I have some time.


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