In a message dated 98-03-25 10:33:28 EST, Tom writes:
<< I have some data that forms what looks like an oval or ellipse. I would
like to fit a best curve to the points. Does anyone know of a package or
routine or a reference I could use to get to the bottom of this problem?
Thanks a lot in advance. >>
To test for an ellipse of the form x^2/a^2 +y^2/b^2 = 1, you can try this:
1. Put your x - y data into a spreadsheet.
2. Create a third column for y^2.
3. Create a fourth column for the first derivative of y^2 with respect to x,
that is d(y^2)/dx, using finite derivatives.
4. Plot d(y^2)/dx versus x. If it is an ellipse, this plot should be a
straight line with a slope of -2b^2/a^2.