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Plot a choropleth map

Source: R/mf_map_help.R
mf_map_choro.Rd

With the choro map type, mf_map() displays a choropleth map.

In choropleth maps, areas are shaded according to the variation of a quantitative variable. They are used to represent ratios or indices.

Usage

For polygons:

mf_map(x, var, type = "choro",
       breaks = "quantile", nbreaks, pal, rev = FALSE,
       border, lwd = 0.7, col_na = "white",
       alpha, expandBB, extent, bg, add = FALSE, leg_*)

For points:

mf_map(x, var, type = "choro",
       breaks = "quantile", nbreaks, pal, rev = FALSE,
       border, pch = 21, cex = 2, lwd = 0.7, col_na = "white",
       alpha, expandBB, extent, bg, add = FALSE, leg_*)

For lines:

mf_map(x, var, type = "choro",
       breaks = "quantile", nbreaks, pal, rev = FALSE, lwd = .7,
       col_na = "white",
       alpha, expandBB, extent, bg, add = FALSE, leg_*)

Arguments

x

object of class sf

var

name of the variable to map

type

"choro"

breaks

either a numeric vector with the actual breaks, or a classification method name. The main methods are 'quantile', 'equal', 'msd', 'ckmeans' (natural breaks), 'Q6' and 'geom'. See mf_get_breaks for details.

nbreaks

number of classes

pal

a set of colors (hex codes) or a palette name. Palette names can be obtained with hcl.pals. The default palette is the pal_seq palette (see mf_theme).

rev

if pal is a palette name, whether the ordering of the colors should be reversed (TRUE) or not (FALSE)

border

border color for polygons and symbols, a hex code or color name given by colors. The default color for polygons is the highlight color, the default color for points is the background color (see mf_theme).

lwd

border width for polygons and points symbols, lines width

pch

type of symbol to use for points, see pch (points only)

cex

symbols size, 2 means 2 times bigger (points only)

col_na

color for missing values, a hex code or a color name given by colors.

alpha, expandBB, extent, bg, add

arguments described in mf_map

leg_*

legend arguments described in mf_map

Value

x is (invisibly) returned.

See also

mf_map(), mf_distr(), mf_get_breaks(), mf_get_pal()

Examples

mtq <- mf_get_mtq()
pts <- mf_get_mtq("points")
flows <- mf_get_mtq("lines")
# polygons
mtq[6, "MED"] <- NA
mf_map(
  x = mtq, var = "MED", type = "choro",
  col_na = "grey90", pal = "Cividis",
  breaks = "equal", nbreaks = 5, border = "white",
  lwd = .5, leg_pos = "topleft",
  leg_title = "Median Income", leg_title_cex = 1,
  leg_val_cex = .9, leg_val_rnd = -2, leg_no_data = "No data",
  leg_box_cex = c(0.5, 3), leg_box_border = NA, leg_frame = FALSE
)

# points
mf_map(mtq)
mf_map(
  x = pts, var = "MED", type = "choro",
  pch = 21, cex = 3, lwd = 1.2,
  pal = "Teal", border = "white",
  leg_horiz = FALSE, leg_val_big = " ",
  leg_val_rnd = -2, leg_pos = "topright",
  leg_frame = TRUE, add = TRUE
)

# lines
mf_map(mtq, extent = flows)
mf_map(
  x = flows, var = "fij", type = "choro",
  breaks = "equal", nbreaks = 3, add = TRUE,
  lwd = 5, pal = "Burg", leg_horiz = TRUE,
  leg_box_cex = c(.7, 1),
  leg_val_rnd = 0, leg_pos = "bottomleft"
)