# Curve and surface analysis

Hello,

If it is possible, in what way can it be defined in JUniForm module?

Yes it is. Let the following points lying on a sphere

# Reiner Jäger, Tilman Müller, Heinz Saler, Rainer Schwäble: Klassische und robuste Ausgleichungsverfahren
# 1. Auflage, 2005
# ISBN: 3-87907-370-8
# Kugelausgleichung S. 331f

1 14.551  9.495  8.433
2  9.071  5.002 10.892
3 12.865  4.306  8.775
4  9.170  7.898 11.930
5  9.993  9.575 11.745
6 12.152  6.017 11.054

If a sphere is fitted using JUniForm one obtain the following results:

The radius is about r = 5 m. If the radius r is known (with superordinate accuracy), it is possible to restrict the parameters. Let r = 6 m be the known radius. To fix the parameter, go to Properties --> Parameter. Change the Processing type to Fixing, and the Initial guess to 6.

It is almost impossible to derive appropriate approximations, if user defined surfaces are defined. Therefore, you have to disable the option. Go to Adjustment --> Least-squares and uncheck the option Derive initial guess. (To get appropriate approximations, just fit the sphere without restriction beforehand, afterwards add the radius restriction as described above.)

The restricted results are

kind regards
Micha

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