[R] Coloring spaces between lines in xyplot

[Seth W Bigelow]

R-listers:

I am summarizing input I got on a recent query about creating stacked,
colored line plots in xyplot.
The only input I got regarding xyplot was to use the polygon() command, but
this seemed to require some awkward data manipulation.
In contrast, I got several snippets of functional code for use in the
ggplot2 and plotrix packages, both of which produced nice graphs with
minimal effort. (Apparently the filled bands option in the xYplot function
in the Hmisc package will also do this).

### stacked line graphs in plotrix package

x <-matrix(x,nrow=10)         # create matrix of x values
y <-matrix(y,nrow=10)         # create matrix of y values

stackpoly(x,y,stack=TRUE)           # make the graph


### stacked line graphs in ggplot2 package

x <- rep(seq(1,10), 2)        # create column of x values
y <- c(1+1.5*(1:10), 0.2 + 1.3*(1:10) )   # create column of y values
trt <- rep(c("low", "high"), each = 10)   # create column with identify of
treatments

qplot(x, y, fill=trt, geom="area")        # plot the graph

I ended up using ggplot2, because I had to churn out a large number of
these, and the "facets" command allowed me to make panels
in a manner akin to the lattice system.

Thanks to Carl, Hadley, Xie, Jim and Frank for responding.

--Seth Bigelow



Dr. Seth  W. Bigelow
Biologist, Sierra Nevada Research Center
Pacific Southwest Research Station, USDA Forest Service. 1731 Research Park
Drive, Davis CA 95618