I believe the problem could be that xyplot uses grid graphics and plot.new and curve are base graphics functions and the 2 graphics systems (grid and base) don't play nicely together without a little extra work. In general the gridBase package helps them play nicely, but I am not sure that it will be the best approach in your case. I would look at rewriting the effects of curve in a panel function for xyplot using the llines function (notice the 2 'l's at the front) or using only base graphics.
On Wed, Jan 9, 2013 at 9:57 AM, Elisabeth Van Beveren <[email protected]>wrote: > Hey, > > I'm stuck on something I already did before (just a different kind of > database), and whatever I try, it doesn't work anymore. So thanks for your > help. > > Here's how my data approximately looks like: > > year season replicate size freq weight > > 2000 summer ch1 6 1 45 > > 2000 summer ch1 6.5 12 46 > > 2000 summer ch1 7 33 470 > > > > I have 2 years (2000 and 2001) and 2 seizons (winter and summer). I wanted > to plot weight~size, with 2 groups (year and seizon), so here's my > shortened > script for that: > > database$groups=paste(database$seizon,database2$year,sep=" ") > > xyplot(database$weight~database2$size, > > groups=database$groups, > > > par.settings=list(superpose.symbol=list(col=col.list,pch=c(21,16,21,16))), > > auto.key=list(corner=c(0.1,0.9),lines=F,points=T)) > > Which works fine, the problem comes when I try to add 2 exponential curves > to the data (the 2 seizons). I tried this: > > summ=subset(database,seizon=="summer") > > modsumm=nls(summ$weight~exp(a+b*summ$size), data=summ, start=list(a=0,b=0)) > > exposumm=curve(exp(0.05354+0.19872*x), from=0, to=22, add=T, lwd=1, > col="blue",lty=1) > > After having to add plot.new() in the front, the line does or not show up, > or shows up but wrongly placed. I thought this might be because of the > subset, so I wanted to do something like this: > > modsumm=nls(weight~exp(a+b* size), data=engsAGG2[seizon=="summer"], > start=list(a=0,b=0)) > > which returns: "undefined columns selected" > > Thanks in advance for the reply. > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. > -- Gregory (Greg) L. Snow Ph.D. [email protected] [[alternative HTML version deleted]] ______________________________________________ [email protected] 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.
