AddPoints: Add Points to Plot

Description

This function can be used to add point symbols to a plot. Proportional circle symbols may be used to represent point data, where symbol area varies in proportion to an attribute variable.

Usage

AddPoints(x, y = NULL, z = NULL, zcol = 1, crs = NULL, xlim = NULL,
  ylim = NULL, zlim = NULL, inches = c(0, 0.2),
  scaling = c("perceptual", "mathematical"), bg = "#1F1F1FCB",
  bg.neg = NULL, fg = NA, lwd = 0.25, cex = 0.7, format = NULL,
  legend.loc = "topright", inset = 0.02, breaks = NULL,
  break.labels = NULL, quantile.breaks = FALSE, make.intervals = FALSE,
  title = NULL, subtitle = NULL, add = TRUE, ...)

Arguments

x, y

numeric or SpatialPoints*. The x and y coordinates for the centers of the circle symbols. If numeric, can be specified in any way which is accepted by xy.coords.

numeric, integer, or factor. Attribute variable. For objects of class factor, a fixed radius is used for circle symbols, see inches argument description.

zcol

integer or character. Attribute name or column number to extract from if x is of class SpatialGridDataFrame.

crs

character or CRS. Coordinate reference system arguments

xlim

numeric. Vector of length 2 giving the x limits for the plot.

ylim

numeric. Vector of length 2 giving the y limits for the plot.

zlim

numeric. Vector of length 2 giving the z limits for the plot.

inches

numeric. Vector of length 2 giving the radii limits for the drawn circle symbol. Alternatively, a single number can be given resulting in a fixed radius being used for all circle symbols; this overrides proportional circles and the function behaves like the points function.

scaling

character. Selects the proportional symbol mapping algorithm to be used; either "perceptual" or "mathematical" scaling (Tanimura and others, 2006).

character or function. Fill color(s) for circle symbols. A color palette also may be specified.

bg.neg

character or function. Fill color(s) for circle symbols corresponding to negative z values. A color palette also may be specified. For circle symbols corresponding to positive z values, the bg argument is used for color(s).

character. Outer-line color for circle symbols. Specify a value of NA to remove the symbols outer line, and NULL to match the outer-line color with the symbols fill color.

lwd

numeric. Line width for drawing circle symbols.

cex

character. Character expansion factor for legend labels.

format

character. Formatting for legend values, see formatC for options.

legend.loc

character. Position of the legend in the main plot region: "bottomleft", "topleft", "topright", or "bottomright" to denote legend location.

inset

numeric. Inset distance of the legend from the margins as a fraction of the main plot region. Defaults to 2 percent of the axis range.

breaks

numeric. Set of finite breakpoints for the legend circle symbols.

break.labels

character. Vector of break labels with length equal to breaks.

quantile.breaks

logical. If true, breaks are set to the sample quantiles of z.

make.intervals

logical. If true, represent z within intervals. See findInterval function for details. Unused if quantile.breaks is true.

title

character. Main title to be placed at the top of the legend.

subtitle

character. Legend subtitle to be placed below the main title.

add

logical. If true, circle symbols (and an optional legend) are added to an existing plot.

...

Graphics parameters to be passed to PlotMap. Unused if add = TRUE.

Value

Used for the side-effect of a bubble map drawn on the current graphics device.

References

Tanimura, S., Kuroiwa, C., and Mizota, T., 2006, Proportional Symbol Mapping in R: Journal of Statistical Software, v. 15, no. 5, 7 p.

Examples

Run this code

set.seed(2)

n <- 50L
x <- cbind(runif(n, 1, 10), runif(n, 1, 500))
z <- runif(n, 0, 1000)
z[sample.int(n, 2)] <- 0
AddPoints(x, z = z, fg = "#00000080", lwd = 0.5, title = "Title",
          subtitle = "Subtitle", add = FALSE)

idxs <- sample.int(n, floor(n / 2))
z[idxs] <- -z[idxs]
AddPoints(x, z = z, bg.neg = "#2A8FBDCB", breaks = pretty(z, n = 8),
          legend.loc = "bottomleft", add = FALSE)

Pal1 <- colorRampPalette(c("#CA0020CB", "#F4A582CB"), alpha = TRUE)
Pal2 <- colorRampPalette(c("#0571B0CB", "#92C5DECB"), alpha = TRUE)
AddPoints(x, z = z, bg = Pal1, bg.neg = Pal2, add = FALSE)

AddPoints(x, z = z, bg = Pal1, bg.neg = Pal2, add = FALSE, make.intervals = TRUE)

AddPoints(x, z = z, bg = Pal1, bg.neg = Pal2, add = FALSE, make.intervals = TRUE,
          inches = 0.1)

AddPoints(x, z = abs(z), title = "Quantiles", bg = topo.colors, quantile.breaks = TRUE,
          add = FALSE)

z <- as.factor(rep(c("dog", "cat", "ant", "pig", "bat"), length.out = n))
AddPoints(x, z = z, bg = rainbow(nlevels(z), end = 0.8, alpha = 0.8), add = FALSE)

AddPoints(x, legend.loc = NULL, add = FALSE)