EMtriangle {colourvision} R Documentation

## Endler and Mielke (2005) triangle colour space

### Description

Plots a triangle colour space for trichromatic Endler and Mielke (2005) colour vision model.

### Usage

```EMtriangle(x, y, type=c("length", "edge"), vnames=c("u","s","m"),
ylim=c(-0.9,0.9), xlim=c(-0.9,0.9),
pch=16, bty="n",yaxt="n",xaxt="n",
col="black", asp=1, ann=FALSE, vectors=FALSE, ...)
```

### Arguments

 `x` x-coordinate `y` y-coordinate `type` Whether the colour space should be built with a fixed vector length, or a fixed edge length (distance between vertices). `vnames` Vector names `ylim` see `plot` function. `xlim` see `plot` function. `pch` see `par` function. `bty` see `par` function. `yaxt` see `par` function. `xaxt` see `par` function. `col` see `par` function. `asp` see `plot` function. `ann` see `par` function. `vectors` Whether vectors representing direction of photoreceptor outputs should be plotted. `...` Other arguments passed to `plot`.

### Details

The original model is available for tetrachromatic animals only. Trichromatic version is implemented in `colourvision` based on Pike (2012) formula. The triangle is built either with a vector length = 0.75 or a edge length = sqrt(3/2), to match the tetrahedron proposed by Endler and Mielke (2005). Doris Gomez derived a trichromatic version which is available in software AVICOL (Gomez, 2006) and was previously implemented here (`colouvision v0.1`).

### Author(s)

Felipe M. Gawryszewski f.gawry@gmail.com

### References

Endler, J. A., and P. Mielke. 2005. Comparing entire colour patterns as birds see them. Biol J Linn Soc 86:405-431.

Pike, T.W. 2012. Generalised chromaticity diagrams for animals with n-chromatic colour vision. Journal of Insect Behavior 255: 277-286.

Gomez, D. 2006. AVICOL, a program to analyse spectrometric data. Last update october 2011. Free executable available at:
http://sites.google.com/site/avicolprogram/ or from the author at dodogomez@yahoo.fr

`EMtetrahedron`, `EMmodel`
```EMtriangle(x=0,y=0, type="length", pch=16, col="red")