[OSM-talk] Changed highway=*_link meaning?!

[Ed Avis]

John Smith <deltafoxtrot256 <at> gmail.com> writes:

[proposal for 'virtual tags' generated automatically]

>>As well as taking care of the different kinds of
> link road, these could also provide 'is_in', 'leading_to' and 'dead_end' for
> 
>dead_end can't be guessed at, it could be bad mapping, is_in is
>redundant, you can use admin boundaries to derive this.

I think you misunderstand my proposal.  I agree that is_in is redundant and
should not be added to the map.  As you say, it can be derived from admin
boundaries.  However, not every programmer might want to have to download all
the admin boundaries and work out what is in what.  Conceivably, it might help
some applications if there were an option for the server to automatically add
is_in tags, generated from admin boundaries, when some map XML is downloaded.
That way the code to work it out only has to be written once.

A road could appear as a dead end because of bad mapping - but then anything else
on the map could also be bad mapping rather than reality.  Anyway it's just an
example.

>>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.  (And if elevation is tagged, uphill
and downhill markers can be deduced for certain.)

-- 
Ed Avis <eda at waniasset.com>