"Fabian" <fabian.conrad@gmx.de> wrote in message <ghl5o5$29q$1@fred.mathworks.com>...
> I've got a matlab procedure that fits an ellipse to a set of points, my problem is that I only need a certain x range and xstep in cartesian coordinate system. Can somebody help me with a formula for y as a function of x and my ellipse (defined by [z, a, b, alpha] returned by fitellipse:)
> %parameterised by 0 <= theta < 2*pi is:
> X = Z + Q(alpha) * [a * cos(theta);b * sin(theta)]
I'm not sure I understand your question but my interpretation is you want to display only a segment of the ellipse. You also want to control the number of points in the ellipse.
To display a segment, either set a theta_min and theta_max or to control it in x use a for loop around the plot.
To control the number of points, say N, set
theta=theta_min:N:theta_max;
Hope this helps
Chris
