[R] problem adding curve/abline

[David Winsemius]

On Jan 10, 2013, at 12:04 PM, Greg Snow wrote:

> 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.
> 

There is a lattice function `panel.curve` that might make this all "hang together" rather than "hanging separately".

-- 
David.
> 
> On Wed, Jan 9, 2013 at 9:57 AM, Elisabeth Van Beveren <elisvb at hotmail.com>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]]
>> 
>> ______________________________________________
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>> 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.
> 538280 at gmail.com
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.

David Winsemius
Alameda, CA, USA