At 2010-03-04 09:38, McGuire, Matthew wrote: >... >A road's Observed Character is what kind of road it appears to be to a >person on the road. For general purpose maps, using observed character to >classify the roads intends to match a person expectations to what they see >on the ground. Character is highly correlated with function, but is not >the same. > >I think Observed Character is what OSM is trying to achieve with the >highway tag. I think this because the OSM tag descriptions for highways >have photos and describe how the road looks, and you cannot determine >system or function from a photograph. I also think it is what the Census >Feature Class Code definitions describe.
I disagree. Even if this is what was intended, it's certainly less useful than the others. When I zoom out a certain amount, what I want to see is the local (aka residential in OSM) roads disappear. Further out still, I want to see the tertiary roads disappear, etc. This is what's useful when trying to map a route through an unknown area - you want to stick to the main roads that get you there with better road conditions, fewer intersections, etc. As an example, in this area: http://www.openstreetmap.org/?lat=34.426&lon=-117.664&zoom=11&layers=B000FTF , 2-land paved roads are few and far between, making them important tertiary or secondary connections. A road with the same characteristics in the city would be unclassified, as there are much better roads. It's all relative to the area, which is why I don't think it's reasonable to classify by any objective characteristics - you have to know or survey the area in order to know how to classify them. Perhaps some people with a lot of experience may be able to do this from satellite imagery. I believe this closely matches what I see in transportation sections of a city's general plan. I think it's useful to use these as guidelines when classifying roads. Many cities/counties of any reasonable size make these available on their website. They usually have: - freeway, expressway, etc. = OSM motorway or trunk - primary arterial = OSM primary - secondary arterial = OSM secondary - minor arterial and/or collector = OSM tertiary - local = OSM residential or unclassified -- Alan Mintz <[email protected]> _______________________________________________ Talk-us mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-us
