On 12/2/07, Dylan Beaudette <[EMAIL PROTECTED]> wrote: > Hi, > > I have noticed an odd inconsistency when plotting a 'step' function > (type='s') in xyplot() vs. plot(). > > For example, given the following data: > > ## generate some profile depths: 0 - 150, in 10 cm increments > depth <- seq(0,150, by=10) > ## generate some property: random numbers in this case > prop <- rnorm(n=length(depth), mean=15, sd=2) > ## since the 0 is not a depth, and we would like the graph to start from 0 > ## make the first property row (associated with depth 0) the same as the > second > ## property row > prop[1] <- prop[2] > ## combine into a table: data read in from a spread sheet would > already be in this format > soil <- data.frame(depth=depth, prop=prop) > > ## simple depth plot, as steps: looks good! > plot(depth ~ prop, data=soil, ylim=c(150,0), type='s', ylab='Depth', > xlab='Property', main='Property vs. Depth Plot') > > ## now try it with lattice graphics:yuck! > xyplot(depth ~ prop, data=soil, ylim=c(160,-5), type='s', > ylab='Depth', xlab='Property', main='Property vs. Depth Plot') > > it looks like the data isn't rotated (?) correctly - i.e. the axis and > data do not match. > > Now, am I mis-interpreting the meaning of type='s' in lattice graphics?
Yes (though not through any fault of your own). Unile plot(), type='s' in panel.xyplot() sorts the values before doing the steps. This difference was not intentional (originally), but it's been around long enough that I decided to make it a "feature" (i.e., document it) when I discovered it. You can still get what you want by sorting on the y-axis, and you can do that by adding 'horizontal = TRUE'. The more general fix that I had planned was to have panel.points() etc work as plot, so that you could do xyplot(..., type = "s", panel = panel.points) It turns out that I haven't implemented that yet, but it should be in the next update (but you need at least R 2.5.0 to use it). -Deepayan > > here is my R session info: > sessionInfo() > R version 2.4.1 (2006-12-18) > i686-pc-linux-gnu > > locale: > LC_CTYPE=en_US;LC_NUMERIC=C;LC_TIME=en_US;LC_COLLATE=en_US;LC_MONETARY=en_US;LC_MESSAGES=en_US;LC_PAPER=en_US;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US;LC_IDENTIFICATION=C > > attached base packages: > [1] "stats" "graphics" "grDevices" "utils" "datasets" "methods" > [7] "base" > > other attached packages: > lattice > "0.14-17" > > could it be that my version of R and lattice is just too old? > > thanks in advance! > > Dylan > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.