getColors {quickPlot} | R Documentation |
Get and set colours for plotting Raster*
objects
Description
Get and set colours for plotting Raster*
objects
setColors
works as a replacement method or a normal function call.
This function can accept RColorBrewer
colours by name. See examples.
Usage
getColors(object)
setColors(object, ..., n, verbose = getOption("quickPlot.verbose")) <- value
setColors(object, value, n, verbose = getOption("quickPlot.verbose"))
Arguments
object |
A |
... |
Additional arguments to |
n |
An optional vector of values specifying the number of levels from which to interpolate the colour palette. |
verbose |
Numeric or logical. If |
value |
Named list of hex colour codes (e.g., from
|
Value
Returns a named list of colours.
Returns a Raster with the colortable
slot set to values
.
Author(s)
Alex Chubaty
See Also
setColors<-()
, brewer.pal()
, RColorBrewer::ColorBrewer
brewer.pal()
, RColorBrewer::ColorBrewer
,
colorRampPalette()
.
Examples
library(terra)
ras <- rast(matrix(c(0, 0, 1, 2), ncol = 2, nrow = 2))
getColors(ras) ## none
# Use replacement method
setColors(ras, n = 3) <- c("red", "blue", "green")
getColors(ras)
clearPlot()
Plot(ras)
# Use function method
ras <- setColors(ras, n = 3, c("red", "blue", "yellow"))
getColors(ras)
clearPlot()
Plot(ras)
# Using the wrong number of colors, e.g., here 2 provided,
# for a raster with 3 values... causes interpolation, which may be surprising
ras <- setColors(ras, c("red", "blue"))
clearPlot()
Plot(ras)
# Real number rasters - interpolation is used
ras <- rast(matrix(runif(9), ncol = 3, nrow = 3)) |>
setColors(c("red", "yellow")) # interpolates when real numbers, gives warning
clearPlot()
Plot(ras)
# Factor rasters, can be contiguous (numerically) or not, in this case not:
ras <- rast(matrix(sample(c(1, 3, 6), size = 9, replace = TRUE), ncol = 3, nrow = 3))
levels(ras) <- data.frame(ID = c(1, 3, 6), Names = c("red", "purple", "yellow"))
ras <- setColors(ras, n = 3, c("red", "purple", "yellow"))
getColors(ras)
clearPlot()
Plot(ras)
# if a factor raster, and not enough labels are provided, then a warning
# will be given, and colors will be interpolated
# The level called purple is not purple, but interpolated betwen red and yellow
suppressWarnings({
ras <- setColors(ras, c("red", "yellow"))
clearPlot()
Plot(ras)
})
# use RColorBrewer colors
setColors(ras) <- "Reds"
clearPlot()
Plot(ras)