plot.Map {maptools}R Documentation

Plot a Map object

Description

The function plots a map object directly from the imported shapefile data.

Usage

plot.Map(x, recs, auxvar = NULL, add = FALSE, fg = "gray", ol = "black", 
  prbg = NULL, glyph = 16, type = "q", nclass = 5, ...)

Arguments

x a Map object returned by read.shape()
recs a vector with the shapes to plot, if missing defaults to all shapes
auxvar if the Map has polygon shapes, a variable from which to derive polygon fill colours using the computed class intervals
add default FALSE, if TRUE add to existing plot
fg foreground colour, can be used to pass through point and polygon colours, permitting the built-in class interval calculation to be avoided
ol line/boundary colour
prbg if not NULL, draw a rectangle around the plot in this colour
glyph points plotted as this pch code
type default "q" for quantile classes, can also be "e" for equal intervals
nclass number of classes for class intervals
... passed through to plotting functions

Value

If the auxvar variable is not used, the function returns NULL, otherwise it returns the list constructed by maptools:::color.ramp() with components:

ramp vector of colours
col.class vector of classes
breaks class intervals given as argument to cut

Author(s)

Nicholas J. Lewin-Koh, modified by Roger Bivand Roger.Bivand@nhh.no

See Also

read.shape

Examples

x <- read.shape(system.file("shapes/sids.shp", package="maptools")[1])
plot(x)
n <- attr(x$Shapes,'nshps')
nParts <- integer(n)
for (i in 1:n) nParts[i] <- attr(x$Shapes[[i]], "nParts")
table(nParts)
cols <- c("azure", "blue", "orange")
fgs <- cols[nParts]
plot(x, fg=fgs)
res <- plot(x, auxvar=x$att.data$BIR74)
str(res)

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