# Ellps

### Purpose

Plots an ellipse on an existing figure.

### Synopsis

- h=ellps(cnt,a,
*lc,ang,pax,zh*)

### Description

ELLPS plots an ellipse on an existing figure e.g. an ellipse of constant Hotelling's T^{2}. The inputs are a 2 element vector containing the ellipse center cnt, and a 2 element vector containing the ellipse axes sizes a. Optional inputs are *lc* which defines the line color (*e.g.* '-g'), and *ang* which defines the angle of rotation from the x-axis {default: ang = 0 radians}.

ellps([4 5],[3 1.5],':g') plots a dotted green ellipse with center (4,5), semimajor axis 3 parallel to the x-axis and semiminor 1.5 parallel to the y-axis.

Optional inputs *pax* and *zh* are used when plotting in a 3D figure. *pax* defines the axis perpendicular to the plane of the ellipse [1 = x-axis, 2 = y-axis, 3 = z-axis], and *zh* defines the distance along the *pax* axis to plot the ellipse.

ellps([2 3],[4 1.5],'-b',pi/4,3,2) plots an ellipse in a plane perpendicular to the z-axis at a height of z = 2.

#### Inputs

**cnt**: vector containing the coordinates of the ellipse center**a**: vector containing ellipse axis sizes

#### Optional Inputs

**lc**: string describing line color and type (same syntax as plot function)**ang**: angle of rotation relative to the x-axis**pax**: axis perpendicular to the plane of the ellipse for 3D figure (1: x-axis; 2: y-axis; 3: z-axis)**zh**: distance along the*pax*axis to plot the ellipse

#### Outputs

**h**: handle to ellipse line object