Ocean colour palette for chlorophyll-a.
Usage
chl_pal(x, palette = FALSE, alpha = 1)
chlPal(x, palette = FALSE, alpha = 1, ...)
Arguments
- x
a vector of data values or a single number
- palette
logical, if TRUE return a list with matching colours and values
- alpha
value in 0,1 to specify opacity
- ...
currently unused
Value
colours, palette, or function, see Details
Details
Flexible control of the chlorophyll-a palette. If x is a
single number, the function returns that many colours evenly
spaced from the palette. If x is a vector of multiple
values the palette is queried for colours matching those values,
and these are returned. If x is missing and palette
is FALSE then a function is returned that will generate n
evenly spaced colours from the palette, as per
colorRampPalette.
References
Derived from a file once found at 'http://oceancolor.gsfc.nasa.gov/DOCS/palette_chl_etc.txt'
Examples
## just get a small number of evenly space colours
plot(1:10, col = chl_pal(10))
## store the full palette and work with values and colours
pal <- chl_pal(palette = TRUE)
## the standard full palette
image(chl, breaks = pal$breaks, col = pal$cols[-1])
