[Tagging] sneaking in tags in the wiki
M∡rtin Koppenhoefer
dieterdreist at gmail.com
Thu Sep 16 15:47:40 BST 2010
2010/9/16 Dave F. <davefox at madasafish.com>:
> On 15/09/2010 21:53, M∡rtin Koppenhoefer wrote:
>>
>> of course stop is also bad. traffic signals is bad as well.
>
> Err... Why?
because it doesn't work well. It is a simplistic approximation to
indicate that a crossing is controlled by traffic lights but when it
comes to details it's a complete fail / undefined.
This is also explicitly written in the wiki: "As of now, there is no
well established convention. "
The wiki also explains why it is a fail: "The horizontal ways are
actually one large way. The problem is how to make sure the
"traffic_signals" is applied to all "ways". To make sure it applies to
the two horizontal ways, we should add the tag to both nodes
intersecting with the vertical way. But that'd make two separate
traffic signals, and there is physically ONE set of traffic signals. "
You can see by this picture (also from the wiki page) that the
vertical way get's punished with 2 traffic lights where there is only
one:
http://wiki.openstreetmap.org/w/images/1/13/Rendering-traffic_singals.jpg
You currently can't model situations where not all ways have traffic
lights, we don't have information about cycles (e.g. many traffic
lights in a row might all turn green at the same time, so they aren't
that big a problem, or they might not, etc.).
Cheers,
Martin
More information about the Tagging
mailing list