plot.polylist

0th

Percentile

Plot polygons

A helper function for plotting polygons in a global bounding box, attempts to handle overplotting internally, holes should be coded by coordinates ordered anti-clockwise. Earlier behaviour requires forcefill=TRUE; this is now default, but will cease to be so from next release. Changes caused by some imported shapefiles data leading to erroneously plotting lakes/islands, and R polygon() overplotting internal polygons. leglabs makes character strings from the same break points. The plot.polylist() function may be used as a generic S3 method. NOTE! plotpolys() DEPRECATED: use generic plot() for polylist objects function instead.

Keywords
spatial
Usage
## S3 method for class 'polylist':
plot(x, col, border = par("fg"), add = FALSE, xlim=NULL,
 ylim=NULL, xlab = "", ylab = "", xpd = NULL, density = NULL, angle = 45, 
 pbg=NULL, forcefill=TRUE, ...)
leglabs(vec, under="under", over="over", between="-")
plotpolys(pl, bb, col = NA, border = par("fg"), add = FALSE, xlim=NULL,
 ylim=NULL, ...)
Arguments
pl, x
list of polygons of class polylist
bb
matrix of polygon bounding boxes - columns are LL(x), LL(y), UR(x), UR(y); note that this argument may be omitted if the polygon list object has an "maplim" attribute, or if both xlim and ylim arguments are given
col
colurs to use for filling the polygons
border
the color to draw the border
add
add to existing plot
xlim, ylim
numeric of length 2, giving the x and y coordinates ranges
xlab, ylab
x and y axis labels, default no label
xpd
(where) should clipping take place?
density
the density of shading lines, in lines per inch
angle
the slope of shading lines, given as an angle in degrees (counter-clockwise)
pbg
colour to be used for hole and background fill, by default NULL (note that par("bg") may be "transparent")
forcefill
default TRUE until next release - fill anyway, if FALSE: believe ring direction as indication of holes/lakes
...
other arguments passed to plot to set the plot window - not passed to polygon
vec
vector of break values
under
character value for under
over
character value for over
between
character value for between
See Also

Map2poly, findInterval

Aliases
  • plotpolys
  • plot.polylist
  • leglabs
Examples
try2 <- read.shape(system.file("shapes/columbus.shp", package="maptools")[1])
mappolys <- Map2poly(try2, as.character(try2$att.data$NEIGNO))
brks <- round(quantile(try2$att.data$CRIME, probs=seq(0,1,0.2)), digits=2)
colours <- c("salmon1", "salmon2", "red3", "brown", "black")
plot(mappolys, col=colours[findInterval(try2$att.data$CRIME, brks,
 all.inside=TRUE)], forcefill=FALSE)
legend(x=c(5.8, 7.1), y=c(13, 14.5), legend=leglabs(brks),
  fill=colours, bty="n")
invisible(title(main=paste("Columbus OH: residential burglaries and vehicle",
 "thefts per thousand households, 1980", sep="")))
try3 <- read.shape(system.file("shapes/sids.shp", package="maptools")[1])
mappolys <- Map2poly(try3, as.character(try3$att.data$FIPSNO))
cols <- c("pink", "orange", "red")
np <- sapply(mappolys, function(x) attr(x, "nParts"))
plot(mappolys, col=cols[np], forcefill=FALSE)
invisible(title(main="White: one part, orange: two part, red: three part polygons"))
plot(mappolys, density=c(10, 20, 30)[np], angle=c(-45, 0, 45)[np],
 axes=FALSE, forcefill=FALSE)
Documentation reproduced from package maptools, version 0.7-22, License: GPL (>= 2)

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