R: Show a colormap with a surface of volcano elevation

pal.volcano {pals} | R Documentation

## Show a colormap with a surface of volcano elevation

### Description

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

### Usage

    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

### 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?

### Value

None.

### 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

[Package pals version 1.5 Index]