calculate_eccentricity.m

Calculates the eccentricity of an ellipse

Description

Determines the eccentricity of an ellipse of an orientation in the xy-plane (i.e. any tilt) by fitting a perfect ellipse to the data and rotating the ellipse to minimize the mean squared error between the fitted ellipse and the data. Should be useful for calculating the eccentricities of orbiting bodies or any closed-loop paths.

• MATLAB release: MATLAB 6.1 (R12.1)

[Cameron Ford]

This is fantastic just what i needed! REALLY didn't want to write a script to work out the eccentricity of 8 points all myself!!

[Divyanshu Vats]

there is a small bug in the code...

x_fit = x_fit - x0;
y_fit = y_fit - y0;

ellipse_rotated = [x_fit(:) y_fit(:) zeros(length(x_fit), 1) ones(length(x_fit),1)] * r;

x_fit = ellipse_rotated(:, 1);
y_fit = ellipse_rotated(:, 2);
x_fit = x_fit + x0;
y_fit = y_fit + y0;

The rotation should be about the origin so we must translate the origin...otherwise works fine..thanks!!