[Tagging] layer=-1, rivers, bridges and tunnels

[Richard Z.]

On Fri, Mar 14, 2014 at 04:51:18PM +0100, Pieren wrote:
> On Fri, Mar 14, 2014 at 4:45 PM, Richard Z. <ricoz.osm at gmail.com> wrote:
> 
> > in theory yes. However "nearby" is a problem as rivers can be very long.
> > Many people simply tag rivers with layer=-1 without even thinking about
> > the fact that the rivers may now collide with tunnels some hundreds of miles
> > away.
> 
> In general, we should avoid single ways running over hundreds of
> miles. And we have QA tools to detect such issues.

well rivers are thousands of miles long. They don't care about QA tools.

> > Furthermore there is a convention that if there is a crossing with a bridge,
> > the bridge should have the layer tag and not the way bellow it. Similar tunnel.
> > For both tunnels and bridges layer is now considered mandatory thus it is
> > totally useless to put rivers at layer=-1 unless they are in a tunnel.
> 
> Who decided this and where ? The wiki about bridge says "Bridges
> should have a layer=*, ". "should" is not "must".

it is a polite "must".

There has been a proposal long ago for bridges to have implicit an layer
and it was not accepted.

Richard