Peter Popov wrote:

> >I would then "move" along this string of points and for every point
> >I would calculate how many points "behind" and "in front" of this point
> >a circle segment could be used for interpolation (within the given
> >"error" limit).
>
> How? I mean, it's trivial for three points, maybe even four, but how
> should I proceed with more points?

I have done some coding trying to find a way to estimate the centre
of a circle for several points.

What I have come up with so far is just a "dirty" way to find it.
It's quite time consuming to parse, so later today I will implement
some macros that does a numerical search for "good" centre points.

I have posted another  image to p.b.i that shows a "height field"
above a plane with 6 points. This the lowest point in this height
field shows where the "best" centre point is for a circle that comes
close to the given points.

The "height field" can be considered as an "error field".
The height above "ground" gives the least "error" generated if
placing the circle below.

The code generating this image also estimates which radius to use
for the circle. And the code can also be used with more or less
points.

Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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