On Wed, Oct 23, 2019 at 12:00:13PM +0200, Tom Pfeifer wrote: > On 23.10.2019 11:35, Florian Lohoff wrote: > > > These are a very common feature, it does seem odd that routers are not > > > supporting them. > > > > The point is that a mini roundabout does need a LOT of preprocessing to > > put it into some graph for your classical A* or Dijkstra. You need to > > eliminate the node and replace it with a circular road much like a > > junction. > > Could you explain what the preprocessing is needed for, and why you need to > replace it in the routing algorithm. > > From my perspective nothing is needed. The routing engine recognises from > which way you come and where to leave, and, since the feature is so small > and clear, it can give instructions like at a normal junction, just using > the tag to describe the junction: > "At the mini-roundabout [turn right|go straight|turn left]".
You would expect (as you see a roundabout sign) to get instructions to take the n.th exit. The roundabout change which triggered this mail is MUCH larger - And you physically can go straight but there is a small curb - so cars will use the circular road, trailers will possible use the curbed center with the last axles. > Basically the mini-roundabout is effectively more about who has priority, > and here all incoming roads have to 'give way'. Similar a four-side "stop" > sign in the US. I have used them in Britain and they are often just a bucket > of white paint poured in the middle of a junction. A mini_roundabout has the same rules as normal roundabout from what i look at the definition. The only difference is that its physically traversable. Flo -- Florian Lohoff [email protected] UTF-8 Test: The 🐈 ran after a 🐁, but the 🐁 ran away
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