lattice: loess smooths based on y-axis values

Hi there,

I'm using the lattice package to create an xy plot of abundance vs. depth for 5 stages of barnacle larvae from 5 species. Each panel of the plot represents a different stage, while different loess smoothers within each panel should represent different species.

However, I would like depth to be on the y-axis and abundance to be on the x-axis, because this is more intuitive as an oceanographer. The smoothing curves would then represent the abundance profiles with depth of the larvae. I have tried just switching depth and abundance in the plot formula/coding, but this means that the loess smoother is based on averaging depth values for each abundance, which means that the curves give multiple possible abundances at each depth level. Rather, I would like the loess smooth to still be based on 'averaging' abundance at each depth.

Essentially, I would like a mirror image of the plot from this code:

ord<-order(Zoo_nocyp$Depth_m, decreasing=TRUE)
xyplot(log10Ab[ord]~factor(-1*Depth_m[ord])|StageF[ord],
         data=Zoo_nocyp[Zoo_nocyp$log10Ab!="0" ,],
         type=c("p","smooth"),
         par.settings=list(strip.background=list(col="white"), fontzize=list(text=16,points=10), lty = 0),
         space=0, border=NA,
         col=c("blue","red","green","purple","orange"),
         stack=TRUE, groups=Zoo_nocyp$SpeciesF,
         key=
           list(title="Species", cex.title=1,text=list(c("BB","BC","CH","SB","VS")),space="right",
                rectangles=list(size=2, border="white",col=c("blue","red","green","purple","orange"))),
         xlab="depth (m)", ylab="log10 abundance",
         layout=c(2,3))

which is different to what you get when you switch log10Ab and Depth_m.

Is there any way to specify the smoothers to be based on sequential y-axis values, rather than x? Or to get the mirror image of a plot?

I can provide a dataset offline, for those interested.

Thanks very much,

Raeanne


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