fields (version 5.02)

colorbar.plot: Adds color scale strips to an existing plot.

Description

Adds one or more color scales in a horizontal orientation, vertical orientation to an existing plot.

Usage

colorbar.plot(x, y, strip, strip.width = 0.1, strip.length = 4 * strip.width, 
zrange = NULL, adj.x = 0.5, adj.y = 0.5, col = tim.colors(256), 
horizontal = TRUE, ...)

Details

This function draws the strips as a sequence of image plots added to the existing plot. The main work is in creating a grid ( x,y) for the image that makes sense when superimposed on the plot. Note that although the columns of strip are considered as separate strips these can be oriented either horizontally or vertically based on the value of horizontal. The rows of zrange are essentially the zlim argument passed to the image function when each strip is drawn.

Don't forget to use locator to interactively determine positions. text can be used to label points neatly in conjunction with setting adj.x and adj.y. Although this function is inefficient for placing images at arbitrary locations on a plot the code can be easily adapted to do this.

This function was created to depict univariate posterior distribution on a map. The values are quantiles of the distribution and the strips when added under a common color scale give an overall impression of location and scale for several distributions.

See Also

image.plot, arrow.plot, add.image

Examples

# set up a plot but don't plot points  and no "box"
plot( 1:10, (1:10)*10, type="n", bty="n") 
# of course this could be anything 

y<- cbind( 1:15, (1:15)+25)

colorbar.plot( 2.5, 30, y)
points( 2.5,30, pch="+", cex=2, adj=.5)
# note that strip is still in 1:8 aspect even though plot has very 
# different ranges for x and y. 

# adding legend using image.plot
zr<- range( c( y))
image.plot( legend.only=TRUE, zlim= zr) 
# see help(image.plot) to create more room in margin etc. 

zr<- rbind( c(1,20), c(1,100)) # separate ranges for columns of y. 
colorbar.plot( 5, 70, y, adj.x=0, zrange= zr)
# some reference lines to show placement
xline( 5, lty=2) # strip starts at x=5 
yline(70, lty=2)  # strip is centered around y=7 (because adj.y=.5 by default)

# many strips on common scale.

y<- matrix( 1:200, ncol=10)
colorbar.plot( 2, 75, y, horizontal=FALSE, col=rainbow(256)) 

# Xmas strip
y<- cbind( rep( c(1,2),10))
y[15] <- NA # NA's should work 
colorbar.plot( 6, 45, y, adj.y=1,col=c("red", "green"))
text(6,48,"Christmas strip", cex=2)

# lennon thumbnail
# there are better ways to this ... see add.image for example.
data( lennon)
colorbar.plot( 7.5,22, lennon, 
           strip.width=.25, strip.length=.25, col=grey(seq( 0,1,,256)))