Show palettes and colormaps as colored bands

Show palettes as colored bands.

pal.bands(
  ...,
  n = 100,
  labels = NULL,
  main = NULL,
  gap = 0.1,
  sort = "none",
  show.names = TRUE
)

Arguments

...	Palettes/colormaps, each of which is either (1) a vectors of colors or (2) a function returning a vector of colors.
n	The number of colors to display for palette functions.
labels	Labels for palettes
main	Title at top of page.
gap	Vertical gap between bars, default is 0.1
sort	If sort="none", palettes are not sorted. If sort="hue", palettes are sorted by hue. If sort="luminance", palettes are sorted by luminance.
show.names	If TRUE, show color names

Details

What to look for:

1. A good discrete palette has distinct colors.

2. A good continuous colormap does not show boundaries between colors. For example, the rainbow() palette is poor, showing bright lines at yellow, cyan, pink.

Examples

pal.bands(c('red','white','blue'), rainbow)

op=par(mar=c(0,5,3,1))
pal.bands(cubehelix, gnuplot, jet, tol.rainbow, inferno,
  magma, plasma, viridis, parula, n=200, gap=.05)
par(op)

# Examples of sorting
labs=c('alphabet','alphabet2', 'glasbey','kelly','polychrome', 'watlington')
op=par(mar=c(0,5,3,1))
pal.bands(alphabet(), alphabet2(), glasbey(), kelly(),
  polychrome(), watlington(), sort="hue",
  labels=labs, main="sorted by hue")
par(op)
pal.bands(alphabet(), alphabet2(), glasbey(), kelly(),
  polychrome(), watlington(), sort="luminance",
  labels=labs, main="sorted by luminance")