[OSM-talk] Mapping everything as areas

[andrzej zaborowski]

2009/11/26 Anthony <osm at inbox.org>:
> 2009/11/26 Morten Kjeldgaard <mok at bioxray.dk>:
> How would you measure the distance from, for example, B->D?  It's not
> a straight line.
>
> A minor error, I suppose, for an intersection, especially a simple
> intersection like the one you've outlined, but if the concept is going
> to be extended beyond intersections, the error could potentially be
> expanded as well.  And if we're going to take the time to carefully
> micromap an intersection as an area, we might as well be as accurate
> as possible.

You can calculate the shortest path from A to B that lies entirely
within the polygon, but:
1. the vehicle is not (usually) a point, it has a width and length,
the shortest path will be different for a lorry and a bike,
2. a car is not going to take the shortest path either, it has to
align to: the traffic rules, how tight a turn it can make, etc.

Most of the times it's going to be using the middle of some lane
independent of the vehicle size so the way we have the centrelines on
the map is really convenient.

Cheers