[talk-au] Mini Roundabouts.

John Henderson snowgum at gmx.com
Sun May 2 14:21:04 BST 2010


On 02/05/10 22:37, Steve Bennett wrote:

> It's not just "rendering" - it also affects how it appears on a GPS.
> Presumably more accurate circles mean more accurate distance
> calculations, too. These aren't terribly important considerations, but
> worth bearing in mind the next time we're having a "but all
> information is important! we must be as accurate as possible in all
> circumstances!" debate.

Not really.  The diameter of the roundabout is going to have a much 
greater bearing on "total distance" than the number of nodes.  Diameter 
is something very difficult to get even approximately right when using a 
GPS as the data source.  And equally important for the distance 
calculation is the degree of "cutting the corner" by individual drivers 
when negotiating said roundabouts.

John H




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