Perceptually uniform palettes for commonly used
variables in oceanography as functions taking an integer
and producing character vectors of colours.
See Thyng, K.M., Greene, C.A., Hetland, R.D., Zimmerle, H.M.
and S.F. DiMarco (2016)
This is cmocean palettes packaged for R.
Guidelines followed when creating these palettes are described in Thyng, K.M., Greene, C.A., Hetland, R.D., Zimmerle, H.M. and S.F. DiMarco (2016).