# drawEllipse: Function to Draw Ellipses In rettopnivek/utilityf: Useful Functions for Modeling and Plotting

## Description

This function will draw an ellipse on a plot that already exists.

## Usage

 ```1 2``` ```drawEllipse(a, b, k = 0, Xc = 0, Yc = 0, deg = T, lngth = 100, draw = T, ret = F, ...) ```

## Arguments

 `a` the length of the x-axis vertice of the ellipse. `b` the length of the y-axis vertice of the ellipse. `k` the angle between the x-axis in the major vertice for the ellipse. `Xc` the center on the x-axis for the ellipse. `Yc` the center on the y-axis for the ellipse. `deg` if TRUE, assumes k is in degrees; otherwise, k is assumed to be in radians. `lngth` the number of points to use when plotting the ellipse. `draw` if TRUE, draws a polygon in the shape of the ellipse on an existing plot. `ret` if TRUE, returns a matrix with the x and y values for the ellipse. `...` additional parameters for the polygon function.

## Value

If `ret` is set to TRUE, returns the x and y-axis values that were passed into the `polygon` function.

## Examples

 ```1 2 3 4``` ```plot( c(-1,1), c(-1,1), type='n', xlab='X-axis', ylab='Y-axis' ) drawEllipse( .2, .2 ) ex = drawEllipse( .5, .2, Xc = -.5, Yc = .5, k = 20, ret = T, col = 'green') drawEllipse( .05, .3, Xc = .5, Yc = -.5, k = 290, col = 'red') ```

rettopnivek/utilityf documentation built on July 20, 2018, 7:50 p.m.