[OSM-talk] Layer defaults for bridge and tunnel

[Robin Paulson]

2008/6/15 Susanna Björverud <susanna.bjorverud at telia.com>:
> Hi,
>
> AFAICT the keys bridge and tunnel do currently not assume any default value
> for layer apart from the normal layer=0 that holds for all objects. While it
> of course is necessary to be able to specify the layer for both of these
> keys, it also seems to me that the "normal" case is that bridge should imply
> layer=1 and tunnel layer=-1. The wiki pages for bridge already states "In
> the easiest case the bridge gets the tag layer=1" and the one for tunnel "In
> the easiest case the tunnel gets the tag layer=-1"
>
> When looking at a new area in JOSM, I as a rule run the validator, and one
> of the most frequent (in my totally unscientific, with no statistics to back
> it up gut-feeling) "mistakes" that it warns about (crossing ways) is bridges
> and tunnels without an accompanying layer tag. If I knew how I would try to
> verify this against the database... but alas I do not.
>
> I would therefore like to suggest that if it is possible bridge=yes should
> in the absence of a layer tag be interpreted as layer=1 and that tunnel=yes
> in the absence of a layer tag should be interpreted as layer=-1, in the same
> way as a junction=roundabout implies oneway=yes etc.

personally, i would prefer if this were implemented at the editor
level - i.e. when i add a 'bridge = yes' tag, it also adds a 'layer=1'
tag as well, so i can either accept, or occasionally change it. where
possible, and appropriate, i would prefer things like this be in the
open