Intersection line and its error of two best fitting planes

[lynx . abraxas]

Hello!


I have two sets of measured points (in 3D). Points of each set are supposed to
sit on a plane.
Now I want to find the intersection line and its  directional  and  positional
error.

But  I'm  stuck  already  in  solving the problem of the best fitting plane. I
found    lots    of    results    with    the    function    polyfit2d    from
http://www.mathworks.com/support/ftp/optimsv4.shtml  but that is quite old and
does not exist any more. Is there some other function in octave  for  this  by
now?

After  that  how  can  I find the intersection line of the two planes and it's
uncertainty in orientation and position depending on the error  of  the  plane
fit result?

Many thanks for any help or hints
Lynx