Either a vector or matrix giving the values of the color
strip(s). If a matrix then strips are assumed to be the columns.
strip.width
Width of strip as a fraction of the plotting
region.
strip.length
Length of strip as a function of the plotting
region. Default is a pleasing 8 times width.
zrange
If a vector these are the common limits used for
assigning the color scale. Default is to use the range of values in
strip. If a two column matrix, rows are used as the limits for each
strip.
adj.x
Location of strip relative to x coordinate. Most
common values are .5 (centered), 0 (right end at x) and 1 (left end of
at x). These are the same conventions that are used for adj in
positioning text.
adj.y
Location of strip relative to y coordinate.
Same rules as adj.x
col
Color table used for strip. Default is our favorite
tim.colors being a scale from a dark blue to dark red.
horizontal
If TRUE draws strips horizontally. If FALSE strips
are drawn vertically
...
optional graphical arguments that are passed to
the image function.
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.
Author(s)
Doug Nychka
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)))