Some palettes with dark colors at one end of the palette hide the shape of the volcano in the dark colors. Viridis is bad.

pal.volcano(pal, n = 100, main = "")

Arguments

pal

A palette function or a vector of colors.

n

The number of colors to display for palette functions.

main

Main title

Value

None.

Details

What to look for:

1. Can you locate the highest point on the volcano?

2. Are the upper-right and lower-right corners the same elevation?

3. Do any Mach bands circle the peak?

Examples

pal.volcano(parula)
pal.volcano(brewer.rdbu) # Mach banding is bad
pal.volcano(warmcool, main="warmcool") # No Mach band
pal.volcano(rev(viridis(100))) # Bad: peak position is hidden