Author: TheFive
[Added to the original trac issue at 6.37am, Tuesday, 21st June 2011]

I track all occurring circles in the "german forum"
http://forum.openstreetmap.org/viewtopic.php?pid=172656#p172656
Pictures of the circles can be seen in the wiki best practices Self Intersection
http://wiki.openstreetmap.org/wiki/DE:Fixing_OSMI_self_intersection#Kornkreisel_.28Potlach_gerundete_Mehrfache_Kreise.29

Author: TheFive
[Added to the original trac issue at 6.24pm, Tuesday, 21st June 2011]

After Discussion in german forum i have opened a discussion in the editor forum
http://forum.openstreetmap.org/viewtopic.php?pid=172749#p172749

The simple solution is to skip the function from the potlatch main page, as the win of the function is smaller than the loss for the project through wrong data possible resulting in wrong routings.

If there would be a priority between "MINOR" and "MAJOR" I would choose this one.

Author: TheFive
[Added to the original trac issue at 7.16pm, Tuesday, 21st June 2011]

an uncorrected circle can be found here
http://www.openstreetmap.org/browse/way/36747683
I mark him with a reference to this trac entry.

Author: TheFive
[Added to the original trac issue at 7.21pm, Tuesday, 21st June 2011]

http://www.openstreetmap.org/browse/way/36747683

May be you can extract Version 3 of this circle with the nodes in the version 3 position to reproduce this error.

Author: Richard
[Added to the original trac issue at 8.12pm, Tuesday, 21st June 2011]

Will look into it. But seriously, what is it with you guys and complete inability to spell PotlaTch? ;)

Author: Mark_S
[Added to the original trac issue at 5.17pm, Tuesday, 6th September 2011]

Example

Take this correct way: http://www.openstreetmap.org/browse/way/4413317

Edit in potlatch 2 and zoom in a bit. On the north-west of the roundabout is a node that is only on the roundabout. Drag this node down and right, into the roundabout so it creates a right angle with the two adjacent nodes. Select the way. Click the circle tool. A double circle is created.

Alternatively take the same node and drag down and left so it is just outside of the previous node on the way. Select the way. Click the circle. A double roundabout is created.

It looks as if the roundabout goes back on itself for a node (from a latitude/longitude point of view) then double circles are created.

Author: chris66
[Added to the original trac issue at 2.54pm, Friday, 9th September 2011]

How I can produce a 14-loop-circle:

1. draw a square[[BR]]
2. select the square and hit the 'make circle' button[[BR]]
3. shift 2 points like this:

[http://up.picr.de/8148719gxf.png]

4. select the line and hit the 'make circle' button

Author: stevage
[Added to the original trac issue at 1.53pm, Thursday, 22nd March 2012]

Fixed: systemed/potlatch2#49

The issue is the logic used to fill in the gaps between nodes. If the next node goes 10 backwards, that's like 350 - requiring 350/20 extra nodes to be added.

My patch detects these situations and simply shows an error and bails out of the whole process. I think some fringe situations may still trigger it, but they're much less likely.