maptools (version 0.4-1)

plot.Map: 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:
  • rampvector of colours
  • col.classvector of classes
  • breaksclass intervals given as argument to cut

See Also

read.shape

Examples

Run this code
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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