# Ellipse

### Description

This function is called internally from the graphical functions `caellipse`

and `nscaellipse`

.
It constructs the algebraic ellipses of confidence.

### Arguments

`hlaxa` |
The length of the horizontal ellipse semi-axis. |

`hlaxb` |
The length of the vertical ellipse semi-axis. |

`xc` |
The coordinate of the generic point on the horizontal axis. |

`yc` |
The coordinate of the generic point on the vertical axis. |

`col` |
The color of ellipses. |

### Note

This function is called from the secondary graphical function `caellipse`

or `nscaellipse`

, which is
called from the main plot function `plot.CAvariants`

and it can be executed
for all variants of correspondence analysis.

### Author(s)

Rosaria Lombardo and Eric J Beh

### References

Beh EJ and Lombardo R 2014 Correspondence Analysis: Theory, Practice and New Strategies. John Wiley & Sons.

Macdonald PDM 2002 Drawing an ellipse in Splus or R.

Available at www.math.mcmaster.ca/peter/s4m03/s4m03_0102/ellipse.html (accessed August 18, 2016).