[OSM-talk] What's the policy on unsurveyed roads from imagery?

[John Smith]

2009/12/27 Anthony <osm at inbox.org>:
> I have this insane theory that if the renderers just outright refused to
> color roads without speed limit tags, these tags would get added a lot
> quicker.  Once you have roads and speed limits, the question of "which roads
> are the quickest way to go usually" can be determined by an algorithm.

In Australia there is this legacy speed limit sign for people with
racing licenses that they can drive any speed they wish, everyone else
is limited to 100, how exactly do you map that? (and I saw one such
sign only the day before yesterday).

Also, the average speed you can drive isn't just a function of speed
limit, but radius of curves and even hills, but curve radius isn't
always mapped accurately and hills aren't mapped at all. So this sort
of subjective decision making isn't any better than the subjective
suggestions I made.

> I guess to some extent it's a question of whether or not a street map
> database without speed limits is "good enough".  I'd say it is not.  At
> least not in the more heavily populated areas of the world.  I suppose all
> the bicyclists in OSM would disagree with that, but they don't have much use
> for primary/secondary/tertiary designations either, do they?

Dunno about your part of the world, but cyclists still have to obey
all road signs here including speed limits. So they too may benefit
from speed information, and I'd love nothing more than to have a speed
limit for each way, but that just doesn't exist at present and isn't
always a good indication of average rate of travel on any particular
way.

> Mapping a road "the wrong color" when there aren't any traffic_calming tags
> is another great way to get people adding appropriate tags.

I think you'll have an up hill battle on your hands trying to get most
others to agree, people have expectations of maps and that includes
major through fares being significantly differentiated from
residential streets.

> Yes, it's an endless debate, so I'll try not to spend too much time on it.
> I think it is useful to point out the problems every once in a while,
> though.

You mean like the problems with your logic as well? :)