View source: R/colour-mapping.R
col_numeric | R Documentation |
Conveniently maps data values (numeric or factor/character) to colours according to a given palette, which can be provided in a variety of formats.
col_numeric(
palette,
domain,
na.color = "#808080",
alpha = FALSE,
reverse = FALSE
)
col_bin(
palette,
domain,
bins = 7,
pretty = TRUE,
na.color = "#808080",
alpha = FALSE,
reverse = FALSE,
right = FALSE
)
col_quantile(
palette,
domain,
n = 4,
probs = seq(0, 1, length.out = n + 1),
na.color = "#808080",
alpha = FALSE,
reverse = FALSE,
right = FALSE
)
col_factor(
palette,
domain,
levels = NULL,
ordered = FALSE,
na.color = "#808080",
alpha = FALSE,
reverse = FALSE
)
palette |
The colours or colour function that values will be mapped to |
domain |
The possible values that can be mapped. For If |
na.color |
The colour to return for |
alpha |
Whether alpha channels should be respected or ignored. If |
reverse |
Whether the colors (or color function) in |
bins |
Either a numeric vector of two or more unique cut points or a single number (greater than or equal to 2) giving the number of intervals into which the domain values are to be cut. |
pretty |
Whether to use the function |
right |
parameter supplied to |
n |
Number of equal-size quantiles desired. For more precise control,
use the |
probs |
See |
levels |
An alternate way of specifying levels; if specified, domain is ignored |
ordered |
If |
col_numeric
is a simple linear mapping from continuous numeric data
to an interpolated palette.
col_bin
also maps continuous numeric data, but performs
binning based on value (see the base::cut()
function). col_bin
defaults for the cut
function are include.lowest = TRUE
and
right = FALSE
.
col_quantile
similarly bins numeric data, but via the
stats::quantile()
function.
col_factor
maps factors to colours. If the palette is
discrete and has a different number of colours than the number of factors,
interpolation is used.
The palette
argument can be any of the following:
A character vector of RGB or named colours. Examples: palette()
, c("#000000", "#0000FF", "#FFFFFF")
, topo.colors(10)
The name of an RColorBrewer palette, e.g. "BuPu"
or "Greens"
.
The full name of a viridis palette: "viridis"
, "magma"
, "inferno"
, or "plasma"
.
A function that receives a single value between 0 and 1 and returns a colour. Examples: colorRamp(c("#000000", "#FFFFFF"), interpolate="spline")
.
A function that takes a single parameter x
; when called with a
vector of numbers (except for col_factor
, which expects
factors/characters), #RRGGBB colour strings are returned (unless
alpha = TRUE
in which case #RRGGBBAA may also be possible).
pal <- col_bin("Greens", domain = 0:100)
show_col(pal(sort(runif(10, 60, 100))))
# Exponential distribution, mapped continuously
show_col(col_numeric("Blues", domain = NULL)(sort(rexp(16))))
# Exponential distribution, mapped by interval
show_col(col_bin("Blues", domain = NULL, bins = 4)(sort(rexp(16))))
# Exponential distribution, mapped by quantile
show_col(col_quantile("Blues", domain = NULL)(sort(rexp(16))))
# Categorical data; by default, the values being coloured span the gamut...
show_col(col_factor("RdYlBu", domain = NULL)(LETTERS[1:5]))
# ...unless the data is a factor, without droplevels...
show_col(col_factor("RdYlBu", domain = NULL)(factor(LETTERS[1:5], levels = LETTERS)))
# ...or the domain is stated explicitly.
show_col(col_factor("RdYlBu", levels = LETTERS)(LETTERS[1:5]))
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