plotrix (version 3.8-2)

spread.labels: Spread labels for irregularly spaced values

Description

Places labels for irregularly spaced values in a regular staggered order

Usage

spread.labels(x,y,labels=NULL,ony=NA,offsets=NA,between=FALSE,
  linecol=par("fg"),srt=0,...)

Value

nil

Arguments

x,y

x and y data values

labels

text strings

ony

Whether to force the labels to be spread horizontally (FALSE) or vertically (TRUE). Defaults to whichever way the points are most spread out.

offsets

How far away from the data points to place the labels. Defaults to one quarter of the plot span for all, staggered on each side.

between

Whether to place the labels between two sets of points.

linecol

Optional colors for the lines drawn to the points.

srt

Rotation of the labels in degrees.

...

additional arguments passed to text.

Author

Jim Lemon

Details

This function is mainly useful when labeling irregularly spaced data points that are "spread out" along one dimension. It places the labels regularly spaced and staggered on the long dimension of the data, drawing lines from each label to the point it describes.

If between is TRUE, the function expects two points for each label and will attempt to place the labels between two vertical lines of points. Lines will be drawn from the ends of each label to the two corresponding points.

If spreading labels horizontally, the user may wish to rotate the labels by 90 degrees (srt=90). If long labels run off the edge of the plot, increase the xlim for extra room.

References

Cooke, L.J. & Wardle, J. (2005) Age and gender differences in children's food preferences. British Journal of Nutrition, 93: 741-746.

See Also

text, spread.lab (TeachingDemos)

Examples

 # spread labels out in the x dimension using defaults
 x<-sort(rnorm(10))
 y<-rnorm(10)/10
 plot(x,y,ylim=c(-1,1),type="p")
 nums<-c("one","two","three","four","five","six","seven","eight","nine","ten")
 spread.labels(x,y,nums)
 # food preferences of children by sex (Cooke & Wardle, 2005)
 fpkids<-data.frame(Food=c("Fatty/sugary","Fruit","Starchy","Meat",
  "Proc.meat","Eggs","Fish","Dairy","Vegetables"),
  Female=c(4.21,4.22,3.98,3.57,3.55,3.46,3.34,3.26,3.13),
  Male=c(4.35,4.13,4.02,3.9,3.81,3.64,3.45,3.27,2.96))
 plot(rep(1,9),fpkids$Female,xlim=c(0.8,2.2),
  ylim=range(c(fpkids$Female,fpkids$Male)),xlab="Sex",xaxt="n",
  ylab="Preference rating",main="Children's food preferences by sex",
  col="red")
 axis(1,at=1:2,labels=c("Female","Male"))
 points(rep(2,9),fpkids$Male,col="blue",pch=2)
 spread.labels(rep(1:2,each=9),c(fpkids$Female,fpkids$Male),
  fpkids$Food,between=TRUE,linecol=c("red","blue"))