[OSM-talk] Changed highway=*_link meaning?!
dapal at debian.org
Fri Jun 25 07:24:48 BST 2010
On Fri, 25 Jun 2010 06:10:18 +0000 (UTC), Ed Avis wrote:
> John Smith <deltafoxtrot256 <at> gmail.com> writes:
> >>and uphill/downhill for slopes (based on the layer of the endpoints).
> >Layer has nothing to do with elevation, it only indicates which road
> >goes over the other road there may not be any slope involved.
> True, but if a way is tagged highway=steps or slope=yes, it's a pretty safe
> bet that going from layer 0 to 1 is uphill, and 1 to 0 is downhill. Even
> though in theory there is nothing to guarantee that.
Not only theory.
Suppose you have a downhill highway=steps intersecting some other thing below.
It's up to the mapper whether to tag this "thing" layer=-1 or to break the
highway=steps and tag the middle segment layer=1. With your example, instead of
the reality, you'd be ending up with an up followed by a down.
layer=* is just really for the rendering, and shouldn't be used for anything
> (And if elevation is tagged, uphill and downhill markers can be deduced for certain.)
Yes, that is the only safe tag.
. ''`. Debian developer | http://wiki.debian.org/DavidPaleino
: :' : Linuxer #334216 --|-- http://www.hanskalabs.net/
`. `'` GPG: 1392B174 ----|---- http://deb.li/dapal
`- 2BAB C625 4E66 E7B8 450A C3E1 E6AA 9017 1392 B174
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 198 bytes
Desc: not available
More information about the talk