[OSM-newbies] Evalated Walkways

[Bill Ricker]

On Wed, Jan 27, 2010 at 9:47 AM, Dave F. <davefox at madasafish.com> wrote:

> It's my understanding that bridge has an implied tag of level=1. I only add
> level=* when I have multiple bridges crossing each other.
>

Were that the common understanding, the render that did not would be wrong.
But it is only the common Mapnik behavior.

The Map Features description for Bridge does not give such an implication,
it should be listed under implies if it were agreed.
http://wiki.openstreetmap.org/wiki/Key:bridge
instead gives example of proper use

highway <http://wiki.openstreetmap.org/wiki/Key:highway>=primary
<http://wiki.openstreetmap.org/wiki/Tag:highway%3Dprimary>

+ *bridge*=yes
+ layer <http://wiki.openstreetmap.org/wiki/Key:layer>=1

+ name <http://wiki.openstreetmap.org/wiki/Key:name>=*usually the road
over the bridge*
+ ref <http://wiki.openstreetmap.org/wiki/Key:ref>=*

and then specifically states
"Tag layer <http://wiki.openstreetmap.org/wiki/Key:layer>=* is used to
separate things that are physically on different levels.

"The tag *bridge*=* does not imply anything about layers,
"so if your bridge crosses any feature on layer
<http://wiki.openstreetmap.org/wiki/Key:layer>=0 (the default if not
present),

"you should consider adding a layer
<http://wiki.openstreetmap.org/wiki/Key:layer>=1 (or higher)."

The OSM wiki Map Features section docments that a word means in OSM
data as a tag or tag-value.
As Data, it is only valuable to the extent we can maintain consistency.


-- 
Bill
n1vux at arrl.net bill.n1vux at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/newbies/attachments/20100127/91ff3e55/attachment.html>