Create a bubble plot of spatial data

Create a bubble plot of spatial data, with options for bicolour residual plots (xyplot wrapper)

Usage

bubble(obj, zcol = 1, ..., fill = TRUE, maxsize = 3, do.sqrt = TRUE, pch, 
  col = c("#d01c8b", "#4dac26"), key.entries = quantile(data[,zcol]), main, 
  identify = FALSE, labels = row.names(data.frame(obj)), key.space = "right",
  scales = list(draw = FALSE), xlab = NULL, ylab = NULL, panel = panel.bubble,
  sp.layout = NULL, 
  xlim = bbexpand(bbox(obj)[1,], 0.04), 
  ylim = bbexpand(bbox(obj)[2,], 0.04))

Arguments

obj: object of, or extending, class SpatialPointsDataFrame or SpatialGridDataFrame, see coordinates or SpatialPointsDataFrame; the object knows about its spatial coordinates
zcol: z-variable column name, or column number after removing spatial coordinates from x@data: 1 refers to the first non-coordinate column
fill: logical; if TRUE, filled circles are plotted (pch = 16), else open circles (pch = 1); the pch argument overrides this
maxsize: cex value for largest circle
do.sqrt: logical; if TRUE the plotting symbol area (sqrt(diameter)) is proportional to the value of the z-variable; if FALSE, the symbol size (diameter) is proportional to the z-variable
pch: plotting character
col: colours to be used; numeric vector of size two: first value is for negative values, second for positive values. Default colors: 5-class PiYG from colorbrewer.org.
key.entries: the values that will be plotted in the key; by default the five quantiles min, q.25, median q.75, max
main: main plotting title
identify: logical; if true, regular plot is called instead of xyplot, and followed by a call to identify().
labels: labels argument passed to plot if identify is TRUE
...: arguments, passed to xyplot, or plot if identification is required.
key.space: location of the key
scales: scales argument as passed to xyplot
xlab: x-axis label
ylab: y-axis label
panel: panel function used
sp.layout: possible layout items; see spplot
xlim: x axis limit
ylim: y axis limit

Value

returns (or plots) the bubble plot; if identify is TRUE, returns the indexes (row numbers) of identified points.

Author

Edzer Pebesma

Examples

data(meuse)
coordinates(meuse) <- c("x", "y") # promote to SpatialPointsDataFrame
bubble(meuse, "cadmium", maxsize = 2.5, main = "cadmium concentrations (ppm)", 
    key.entries = 2^(-1:4))

bubble(meuse, "zinc", main = "zinc concentrations (ppm)",
    key.entries =  100 * 2^(0:4))