[Talk-us] Changeset to revert (or defend

[Lord-Castillo, Brett]

So, the real argument here is what is a bridge and what is a tunnel? Many people considered depressed highways to be tunnels rather than the roads over them to be bridges. I saw USGS topos mentioned earlier. Not all manmade cuts are reflected in topo lines. Manmade cuts that are structures are not considered bare earth and are left out. But then you get to the weird idea of "are the sides of the depressed highway vertical concrete or sloped ground?" and other such criteria.
--Brett

Brett Lord-Castillo
Information Systems Designer/GIS Programmer
St. Louis County Police
Office of Emergency Management
14847 Ladue Bluffs Crossing Drive
Chesterfield, MO 63017
Office: 314-628-5400
Fax: 314-628-5508
Direct: 314-628-5407



-----Original Message-----

Date: Tue, 25 May 2010 03:02:19 -0400
From: Nathan Edgars II <neroute2 at gmail.com>
Subject: [Talk-us] Changeset to revert (or defend?)
To: talk-us at openstreetmap.org
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	<AANLkTilXddg8qRs15duAlKFOmZ1yuIpUEr3sVpWcX7sQ at mail.gmail.com>
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Frederik Ramm wrote:
>I think it's quite easy. If NE2 has been there to inspect the individual
>intersection he has been changing, or at least thoroughly studied aerial
>imagery or so for this particular intersection, then his idea of how it
>should be tagged is as legit as someone else's and the issue must be
>discussed/battled out for each case individually.
We don't dispute the facts. (Taking the South Innerbelt example) the
freeway is in a shallow valley/cutting, with ramps between the freeway
and its frontage roads, and cross streets intersecting the frontage
roads and passing over the freeway. The only dispute is about tagging:
whether it's appropriate to use layer=-1 for that. Of course, if the
freeway is layer=-1, a drainpipe that passes under the freeway would
need layer=-2. And a landuse polygon would need layer=-1 only where
the freeway is such, and layer=0 on both sides, or otherwise, if
continuous, it would be referring to land on a structure above the
freeway or land under the other streets.

>(Personally, I have no issues with a bridge being layer=0 when stuff
>below it is layer=-1 - we explicitly say that layers are meant to be
>relative only.
Since before I joined (and, in fact, since they were created in 2008),
the wiki pages for layer and key:layer have stated that 0 is for the
ground level, positive numbers are for bridges, and negative numbers
are for tunnels. "The bridge within a perfectly flat street should be
layer=1 even if the stream is as far below it as the Grand Canyon." As
I said, maybe we need a way to mark that this has no consensus (or
actively not mark that it has consensus) if there is truly a lot of
disagreement with it.