radial.plot: Plot values on a circular grid of 0 to 2*pi radians.

Description

Plot numeric values as distances from the center of a circular field in the directions defined by angles in radians.

Usage

radial.plot(lengths,radial.pos=NULL,labels,label.pos=NULL,
 start=0,clockwise=FALSE,rp.type="r",label.prop=1.1,main="",xlab="",ylab="",
 line.col=par("fg"),lty=par("lty"),lwd=par("lwd"),mar=c(2,2,3,2),
 show.grid=TRUE,show.grid.labels=TRUE,show.radial.grid=TRUE,
 grid.col="gray",grid.bg="transparent",
 grid.left=FALSE,grid.unit=NULL,point.symbols=NULL,point.col=NULL,
 show.centroid=FALSE,radial.lim=NULL,poly.col=NULL,...)

Arguments

lengths

A numeric data vector or matrix. If lengths is a matrix, the rows will be considered separate data vectors.

radial.pos

A numeric vector or matrix of positions in radians. These are interpreted as beginning at the right (0 radians) and moving counterclockwise. If radial.pos is a matrix, the rows must correspond to rows of lengths.

labels

Character strings to be placed at the outer ends of the lines. If set to NA, will suppress printing of labels, but if missing, the radial positions will be used.

label.pos

The positions of the labels around the plot in radians.

start

Where to place the starting (zero) point. Defaults to the 3 o'clock position.

clockwise

Whether to interpret positive positions as clockwise from the starting point. The default is counterclockwise.

rp.type

Whether to draw (r)adial lines, a (p)olygon, (s)ymbols or some combination of these. If lengths is a matrix and rp.type is a vector, each row of lengths can be displayed differently.

label.prop

The label position radius as a proportion of the maximum line length.

main

The title for the plot.

xlab,ylab

Normally x and y axis labels are suppressed.

line.col

The color of the radial lines or polygons drawn.

lty

The line type(s) to be used for polygons or radial lines.

lwd

The line width(s) to be used for polygons or radial lines.

mar

Margins for the plot. Allows the user to leave space for legends, long labels, etc.

show.grid

Logical - whether to draw a circular grid.

show.grid.labels

Logical - whether to display labels for the grid.

show.radial.grid

Whether to draw radial lines to the plot labels.

grid.col

Color of the circular grid.

grid.bg

Fill color of above.

grid.left

Whether to place the radial grid labels on the left side.

grid.unit

Optional unit description for the grid.

point.symbols

The symbols for plotting (as in pch).

point.col

Colors for the symbols.

show.centroid

Whether to display a centroid.

radial.lim

The range of the grid circle. Defaults to range(pretty(lengths)).

poly.col

Fill color if polygons are drawn. Use NA for no fill.

...

Additional arguments are passed to plot.

Value

Details

radial.plot displays a plot of radial lines, polygon(s), symbols or a combination of these centered at the midpoint of the plot frame, the lengths, vertices or positions corresponding to the numeric magnitudes of the data values. If show.centroid is TRUE, an enlarged point at the centroid of values is displayed. The centroid is calculated as the average of x and y values unless rp.type="p". In this case, the barycenter of the polygon is calculated. Make sure that these suit your purpose, otherwise calculate the centroid that you really want and add it with the points function. If the user wants to plot several sets of lines, points or symbols by passing matrices or data frames of lengths and radial.pos, remember that these will be grouped by row, so transpose if the data are grouped by columns.

The radial.plot family of plots is useful for illustrating cyclic data such as wind direction or speed (but see oz.windrose for both), activity at different times of the day, and so on. While radial.plot actually does the plotting, another function is usually called for specific types of cyclic data. Note that if the observations are not taken at equal intervals around the circle, the centroid may not mean much.

Examples

Run this code

testlen<-rnorm(10)*2+5
 testpos<-seq(0,18*pi/10,length=10)
 testlab<-letters[1:10]
 oldpar<-radial.plot(testlen,testpos,main="Test Radial Lines",line.col="red",lwd=3)
 testlen<-c(sin(seq(0,1.98*pi,length=100))+2+rnorm(100)/10)
 testpos<-seq(0,1.98*pi,length=100)
 radial.plot(testlen,testpos,rp.type="p",main="Test Polygon",line.col="blue")
 # now do a 12 o'clock start with clockwise positive
 radial.plot(testlen,testpos,start=pi/2,clockwise=TRUE,
  rp.type="s",main="Test Symbols (clockwise)",
  point.symbols=16,point.col="green",show.centroid=TRUE)
 # one without the circular grid and multiple polygons
 # see the "diamondplot" function for variation on this
 posmat<-matrix(sample(2:9,30,TRUE),nrow=3)
 radial.plot(posmat,labels=paste("X",1:10,sep=""),rp.type="p",
  main="Spiderweb plot",line.col=2:4,show.grid=FALSE,lwd=1:3,
  radial.lim=c(0,10))
 # dissolved ions in water
 ions<-c(3.2,5,1,3.1,2.1,4.5)
 ion.names<-c("Na","Ca","Mg","Cl","HCO3","SO4")
 radial.plot(ions,labels=ion.names,rp.type="p",main="Dissolved ions in water",
  grid.unit="meq/l",radial.lim=c(0,5),poly.col="yellow")
 par(xpd=oldpar$xpd,mar=oldpar$mar,pty=oldpar$pty)
 # reset the margins
 par(mar=c(5,4,4,2))