color.scale.lines: Line segments with scaled colors

In plotrix: Various Plotting Functions

Line segments with scaled colors

Description

Display line segments with colors scaled to numeric values.

Usage

 color.scale.lines(x,y,reds,greens,blues,col=NA,colvar=NA,...)

Arguments

x,y	Numeric vectors or a list with at least two components, the first two of which must be named x and y.
reds,greens,blues	Color ranges into which to scale the numeric values.
col	One or more colors to use for the resultant lines. Will be recycled if necessary.
colvar	A numeric vector from which to scale the colors.
...	Additional arguments passed to ‘⁠segments⁠’.

Details

‘⁠color.scale.lines⁠’ displays line segments that can be individually colored according to a variety of methods. In order of precedence, if ‘⁠col⁠’ is not NA, the color values passed will be used. If ‘⁠colvar⁠’ is not NA, the function will call ‘⁠color.scale⁠’ with the three color range arguments to determine the line colors. If ‘⁠colvar⁠’ is the same length as ‘⁠length(x)-1⁠’, exactly enough colors for the number of lines displayed will be calculated. If shorter, some colors will be recycled and if longer, some colors will not be used. Finally, the values in ‘⁠y⁠’ will be color-scaled if both of the above arguments are NA. Thus the user can pass predetermined colors, use colors scaled from an arbitrary vector of numerical values or use the ‘⁠y⁠’ values. See ‘⁠color.scale⁠’ for an explanation of specifying color ranges.

Value

nil

Note

The function is useful for highlighting a numeric dimension or adding an extra "dimension" to a plot.

Author(s)

Jim Lemon

See Also

color.scale

Examples

 # color a random walk "hot" (red) to "cold" (blue) on its distance
 # from the starting point
 x<-c(0,cumsum(rnorm(99)))
 y<-c(0,cumsum(rnorm(99)))
 xydist<-sqrt(x*x+y*y)
 plot(x,y,main="Random walk plot",xlab="X",ylab="Y",type="n")
 color.scale.lines(x,y,c(1,1,0),0,c(0,1,1),colvar=xydist,lwd=2)
 boxed.labels(x,y,labels=1:100,border=FALSE,cex=0.5)
 # now color the lines to show whether each step went away from
 # or toward the starting position
 color.scale.lines(x,y,col=2+(diff(xydist)>0))
 boxed.labels(x,y,labels=1:100,border=FALSE,cex=0.5)

plotrix documentation built on Nov. 10, 2023, 5:07 p.m.