| plot.polylist {maptools} | R Documentation |
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.
## 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, ...)
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 |
Roger Bivand Roger.Bivand@nhh.no
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="\n")))
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)