[Tagging] Stop sign?

L. David Baron dbaron at dbaron.org
Sat Nov 24 06:08:40 GMT 2012


On Wednesday 2012-11-21 08:50 +0000, Kytömaa Lauri wrote:
> >Can we start using relations for this already?  Really seems like that provides the specifics we want for this.
> 
> So far nobody has provided a real world example of a place where the simple distance-to-next would not be correct. If somebody does that, then a relation could be made up.

An example in my neighborhood of San Francisco is the stop signs on
21st Street where it crosses the J-Church MUNI tram line (where the
J-Church is deviating from Church Street to go around a steep hill):
http://www.openstreetmap.org/?lat=37.7566&lon=-122.4269&zoom=18&layers=M

There are stop signs on both sides of the tram line (which I tagged
as nodes with highway=stop).  These are visible in the Bing imagery:
http://www.openstreetmap.org/edit?lat=37.7565&lon=-122.4269&zoom=21
since many urban areas in California have the habit of painting
their stop signs as markings in the road (the word STOP and then a
thick white line, representing the stop line) in addition to using
signs.

The stop sign on the east side of the tram line, however, is (I
think) closer to Chattanooga Street than it is to the tram line.
(Traffic turning left from Chattanooga Street northbound onto 21st
Street westbound must, in theory, stop *twice*, the first time due
to the implicit stop sign from California's rule for unmarked
T-intersections, and then again just after turning for the stop
sign.)

Even worse, there isn't actually an intersection node between 21st
Street and the J-Church tram line.  So I fully admit this is a
particularly hard case [1]; even using
http://wiki.openstreetmap.org/wiki/Proposed_features/Relation:type%3Dstop
would require adding an extra node.

-David

[1] http://en.wikipedia.org/wiki/Hard_cases_make_bad_law

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂



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