[OSM-talk] Misclassified roads

Richard Fairhurst richard at systemeD.net
Wed Jul 9 16:03:23 BST 2008


Steve Hill wrote:

> However, after starting to do this, I've realised just how many of the
> roads are misclassified - I'd estimate that well over 80% of the roads
> tagged as highway=unclassified are, infact, not unclassified roads.

That 80% figure surprises me, a lot.

Most roads _should_ be either unclassified or residential, and it's  
usually pretty easy to tell which one is which - residential is to be  
found in built-up areas with lots of roads.

Looking at
http://www.openstreetmap.org/edit?lat=51.5847&lon=-4.0125&zoom=14

for example, I note you've reclassified Trewyddfa Road as  
unclassified. I don't know the area, but assuming it's not an A- or  
B-road (as NPE suggests), then it's either going to be tertiary,  
unclassified, or residential, in order of importance.

 From the road layout, unclassified looks very sensible. With the  
B4603 Neath Road running parallel, Trewyddfa Road is unlikely to be a  
"significant through route for non-local use, other than an A/B/M  
road" (my working definition of "tertiary"). Yet it clearly carries  
some through traffic, so is unlikely to be just residential.

YMMV may vary, and in fact, this probably comes down to the definition  
of tertiary, which is not generally agreed and certainly needs some  
thought.

But working from the assumption that the original mapper (who I think  
is based nearby) knows the area, then unilaterally removing part of  
his work (which "unclassified"->"road" does) is a pretty hostile thing  
to do, and is the kind of thing that leads to edit wars. If someone  
came round Charlbury and retagged as "road" any roads I'd deliberately  
tagged as unclassified, I'd be pretty pissed off. No, that's not a  
challenge. :p

cheers
Richard





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