flex_legend: Create a legend where you want it

In PrincetonUniversity/lmisc: Miscellaneous functions for plotting and performing various small tasks

Description

Creates a vertical or horizontal legend in a location of your choosing

Usage

flex_legend(ncuts, legend.text, legend.vals, legend.pos, longdims, shortdims,
  colvec, leg.adj = c(0, 0), cex.val = 1, srt.val = 0, horiz = TRUE,
  textside = "bottom", textcol = "black", bordercol = "black")

Arguments

ncuts	Number of intervals for legend
legend.text	Label for the legend (e.g. units)
legend.vals	Vector of labels for the legend
legend.pos	A 1 or 2 element vector that specifies where along vector legend.text should be (details)
longdims	Vector specifying the user coordinates for the legend's long axis (e.g. c(0.2, 0.8))
shortdims	1) anchor user coordinate for the short axis; 2) width of short axis (e.g. c(0.05, 0.02))
colvec	Vector of colors to fill each polygon in vector, equal in length to ncuts
leg.adj	Tweak position(s) of legend.vals and/or legend.text (see details)
cex.val	Adjusts the text size of legend.vals and/or legend.text (see details)
srt.val	Rotation of legend.vals and/or legend.text (see details)
horiz	TRUE (default) or FALSE for horizontal or vertical legend
textside	Specify "bottom" (default) or "top" for side of legend.vals on legend
textcol	Vector of colors for legend.vals and legend.text
bordercol	Outline color for polygon borders in legend

Details

Legend.pos uses a two parameter vector, with the second value specifying the polygon number in the legend next to/above/below which the legend.text will appear, and the first which of the four corners of the polygon it will be closest to. Default values are chosen if just one (which then specifies polygon number)vor no values are provided. leg.adj is passed as either a list of two two element vectors, or a single two element vector. If a list, the first element specifies adjustments for legend.values, and the second element adjustments for the legend.text. If just a vector, then these values are used for both. e.g. list(c(0, 0), c(-1, -0.5)); c(0, -0.5).

Value

A polygon based legend

Examples

library(raster)
r1 <- raster(nrow = 20, ncol = 20)
r1[] <- sample(0:75, ncell(r1), replace = TRUE)
brks <- round(quantile(r1, seq(0, 1, 0.1)))
cols <- colorRampPalette(c("red", "antiquewhite", "blue"))
par(mar = c(5, 4, 0, 0))
plot(r1, axes = FALSE, box = FALSE, legend = FALSE, breaks = brks, col = cols(length(brks) - 1))
flex_legend(ncuts = length(brks) - 1, legend.text = "vals", leg.adj = list(c(0.5, 1), c(0, -0.5)), 
            legend.vals = brks, legend.pos = c(4, 5), longdims = c(0.2, 0.8), shortdims = c(0.08, 0.03), 
            colvec = cols(length(brks) - 1))
dev.off()

par(mar = c(0, 4, 0, 4))
plot(r1, axes = FALSE, box = FALSE, legend = FALSE, breaks = brks, col = cols(length(brks) - 1))
flex_legend(ncuts = length(brks) - 1, legend.text = "vals", textside = "right", 
            legend.pos = c(3, 10), leg.adj = list(c(0.2, 0.5), c(0, -1)), 
            horiz = FALSE, legend.vals = brks, longdims = c(0.2, 0.8), 
            shortdims = c(0.85, 0.02), colvec = cols(length(brks) - 1))
            dev.off()

PrincetonUniversity/lmisc documentation built on May 8, 2019, 3:23 a.m.