AddGradientLegend: Add Color Gradient Legend to Plot

In USGS-R/inlmisc: Miscellaneous Functions for the USGS INL Project Office

Add Color Gradient Legend to Plot

Description

Add a continuous color gradient legend strip to a plot.

Usage

AddGradientLegend(
  breaks,
  pal = GetColors,
  at = NULL,
  n = 5,
  labels = TRUE,
  scientific = FALSE,
  title = NULL,
  strip.dim = c(2, 8),
  ...
)

Arguments

breaks	'numeric' vector. Finite numeric breakpoints for the colors, must be in increasing order.
pal	'function'. Color palette function to be used to assign colors in the legend.
at	'numeric' vector. Points at which tick-marks and labels are to be drawn.
n	'integer' count. Desired number of tick-marks to be drawn. Unused if at argument is specified.
labels	'logical' flag or 'character' vector. Can either be a logical value specifying whether annotations are to be made at the tickmarks, or a vector of labels to be placed at the tickpoints.
scientific	'logical' flag. Whether labels should be formatted for scientific notation, see ToScientific for details.
title	'character' string. Title to be placed at the top of the legend.
strip.dim	'numeric' vector of length 1 or 2, value is recycled as necessary. Dimensions (width and height) of the color strip, in picas.
...	Additional arguments to be passed to the GetInsetLocation function—used to position the legend in the main plot region.

Value

Invisible NULL

Author(s)

J.C. Fisher, U.S. Geological Survey, Idaho Water Science Center

See Also

PlotMap

Examples

plot(NA, xlim = c(0, 100), ylim = c(-10, 10),
     xlab = "x", ylab = "y", xaxs = "i", yaxs = "i")
breaks <- 0:200
AddGradientLegend(breaks, title = "Title", loc = "bottomleft")
AddGradientLegend(breaks, pal = GetColors(scheme = "iridescent"),
                  title = "Title", loc = "bottomleft",
                  inset = c(0.2, 0.1))
AddGradientLegend(breaks, pal = GetColors(scheme = "turbo"),
                  loc = "center", labels = FALSE)
breaks <- seq(0, 2e+06, length.out = 5)
AddGradientLegend(breaks, pal = GetColors(scheme = "discrete rainbow"),
                  scientific = TRUE, strip.dim = c(1, 14),
                  inset = c(0.2, 0.1))
AddGradientLegend(breaks, pal = GetColors(scheme = "YlOrBr"),
                  loc = "topright", inset = 0.1)

USGS-R/inlmisc documentation built on Sept. 17, 2022, 2:38 a.m.