geometry_ellipse index x_c y_c a b tolerance

The coordinate of the center is x_c y_c. The equation for the ellipse is:

$$\left( \frac{x-x\_c}{a} \right)^2 + \left( \frac{y-y\_c}{b} \right)^2 = 1$$

Other data items can check if nodes are located on this geometry. The ellipse can only be used in 2D. All node within a distance tolerance of the ellipse are considered to be part of the ellipse.