Calculates coordinates and colorimetric variables that represent reflectance spectra in the avian tetrahedral color space.

tcspace(vismodeldata)

## Arguments

vismodeldata (required) quantum catch color data. Can be either the result from vismodel() or independently calculated data (in the form of a data frame with four columns name 'u', 's', 'm', 'l', representing the avian cones).

## Value

A data frame of class colspace consisting of the following columns:

• u, s, m, l: the quantum catch data used to calculate the remaining variables. NOTE: even if visual system is of type V-VIS, the output column will be labeled u.

• u.r, s.r, m.r, l.r: relative cone stimulation, for a given hue, as a function of saturation. See Stoddard & Prum (2008) for details.

• x, y, z: cartesian coordinates for the points in the tetrahedral color space.

• h.theta, h.phi: angles theta and phi, in radians, determining the hue of the color.

• r.vec: the r vector (saturation, distance from the achromatic center).

• r.max: the maximum r vector achievable for the colour's hue.

• r.achieved: the relative r distance from the achromatic center, in relation to the maximum distance achievable (r.vec/r.max).

## References

Stoddard, M. C., & Prum, R. O. (2008). Evolution of avian plumage color in a tetrahedral color space: A phylogenetic analysis of new world buntings. The American Naturalist, 171(6), 755-776.

Endler, J. A., & Mielke, P. (2005). Comparing entire colour patterns as birds see them. Biological Journal Of The Linnean Society, 86(4), 405-431.

## Author

Rafael Maia rm72@zips.uakron.edu

## Examples

data(sicalis)
vis.sicalis <- vismodel(sicalis, visual = "avg.uv")
tcs.sicalis <- colspace(vis.sicalis, space = "tcs")