[OSM-talk] When is a bridge not a bridge?

Kenneth Gonsalves lawgon at au-kbc.org
Fri Jan 23 12:48:07 GMT 2009

On Friday 23 Jan 2009 6:00:08 pm Sven Rautenberg wrote:
> > if the way is "layer=0" and the bridge is "layer=0" too
> > (the crossing way under is "layer=-1", digged)
> > then the bridge has no ramps.
> Something with negative layer has to be a tunnel. Bridges are useless if
> there is a tunnel. Do not tag bridges as "layer=0" just because there
> are no ramps. The layer tag is to help a renderer put the ways in the
> right visual order - not to indicate whether or not a way is elevated or
> not. Do not tag ways as "layer=-1" just because they are below the
> general earth surface (such as rivers).

this is important - only underground rivers should be given a -1 layer tag

Kenneth Gonsalves

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