leg_comp: Compose a map legend

In maplegend: Legends for Maps

Compose a map legend

Description

Compose a map legend with several elements. The "type" argument defines the legend type. Please note that some arguments are available for all types of legend and some others are only relevant for specific legend types.

Usage

leg_comp(
  leg,
  type,
  val,
  pal = "Inferno",
  alpha = NULL,
  col = "tomato4",
  inches = 0.3,
  val_max = NULL,
  symbol = "circle",
  self_adjust = FALSE,
  lwd = 0.7,
  border = "#333333",
  pch = 1:seq_along(val),
  cex = rep(1, length(val)),
  title = "Legend Title",
  val_rnd = 0,
  val_dec = ".",
  val_big = "",
  col_na = "white",
  cex_na = 1,
  pch_na = 4,
  no_data = FALSE,
  no_data_txt = "No Data",
  box_border = "333333",
  box_cex = c(1, 1),
  horiz = FALSE
)

Arguments

leg	legend object
type	type of legend: prop for proportional symbols, choro for choropleth maps, cont for continuous maps (e.g. raster), typo for typology maps, symb for symbols maps, prop_line for proportional lines maps, grad_line for graduated lines maps, histo for histograms, choro_point for choropleth points maps, choro_line for choropleth lines maps, choro_symb for choropleth on symbols maps typo_line for typology lines maps.
val	vector of value(s) (for "prop" and "prop_line", at least c(min, max) for "cont"), vector of categories (for "symb", "typo", "typo_line"), break labels (for "choro", "choro_point", "choro_line", "choro_symb", and "grad_line"), histogram parameters (for "histo").
pal	a color palette name or a vector of colors
alpha	opacity, in the range [0,1]
col	color of the symbols (for "prop") or color of the lines (for "prop_line" and "grad_line")
inches	size of the largest symbol (radius for circles, half width for squares) in inches
val_max	maximum value corresponding to the largest symbol or line
symbol	type of symbols, 'circle' or 'square'
self_adjust	if TRUE values are self-adjusted to keep min, max and intermediate rounded values
lwd	width(s) of the symbols borders (for "prop", "symb", "choro_point", "choro_symb"), width of the largest line (for "prop_line"), line width (for "choro_line" and "typo_line"), vector of line widths (for "grad_line")
border	symbol border color(s)
pch	type(s) of the symbols (0:25)
cex	size(s) of the symbols
title	title of the legend
val_rnd	number of decimal places of the values in the legend
val_dec	decimal separator
val_big	thousands separator
col_na	color for missing values
cex_na	size of the symbols for missing values
pch_na	type of the symbols for missing values
no_data	if TRUE a "missing value" box is plotted
no_data_txt	label for missing values
box_border	border color of legend boxes
box_cex	width and height size expansion for boxes, histogram or lines
horiz	if TRUE plot an horizontal legend

Value

A list of legends parameters is returned.

Examples

# minimal example
plot.new()
plot.window(xlim = c(0, 1), ylim = c(0, 1), asp = 1)
box()
leg_comp(type = "prop", val = c(10, 50, 100)) |>
  leg_comp(type = "typo", val = c("A", "B", "C")) |>
  leg_draw()

maplegend documentation built on April 10, 2026, 9:07 a.m.