Thanks John, yes you are right I have add different smooth statements, here
is the code from Dennis for my case:

library(ggplot2)
ggplot(data = df, aes(x=Var1, y=log(Var2), color=SiteID, group=SiteID)) +
    geom_point() +
    geom_smooth(data = subset(df, SiteID != "AL3"), method='lm',
formula= y ~ I(1/x),
                   se=FALSE, size=2) +
    geom_smooth(data = subset(df, SiteID == "AL3"), method = "lm",
                   formula = y ~ log(x), se = FALSE, size = 2)


On Sat, Jul 27, 2013 at 9:14 AM, John Kane <jrkrideau@inbox.com> wrote:

> I have not tried anything like that but have a look at
> www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDkQFjAC&url=http%3A%2F%2Fstackoverflow.com%2Fquestions%2F7476022%2Fgeom-point-and-geom-line-for-multiple-datasets-on-same-graph-in-ggplot2&ei=MfHzUej7FoSergG1_ICYAw&usg=AFQjCNH2b72a6un_xAM-PYxC-sUGU8-xOw&sig2=iBIrl1uhIsJXmPbAh4kUbw&bvm=bv.49784469,d.aWM
>
> You may be able to use two smooth statements to do what you want.
>
> John Kane
> Kingston ON Canada
>
>
> > -----Original Message-----
> > From: yelin@lbl.gov
> > Sent: Fri, 26 Jul 2013 12:21:23 -0700
> > To: r-help@r-project.org
> > Subject: [R] add different regression lines for groups on ggplot
> >
> > Hey All,
> >
> > I need to apply different regression lines to different group on my
> > ggplot,
> > and here is the code I use:
> >
> >
> qplot(x=Var1,y=Var2,data=df,color=SiteID,group=SiteID)+geom_point()+geom_smooth(method='lm',formula=log(y)~I(1/x),se=FALSE,size=2)
> >
> > However the regression for different groups is as below:
> >
> > AL1/AL2: log(y)~I(1/x)
> > AL3: log(y)~log(x)
> >
> > How can I apply each regression equation on the same ggplot?
> >
> > Also I have an issue that if I use the code above, the regression lines
> > are
> > not overlapped on top of my data points.
> >
> > Thanks for your help!
> > ______________________________________________
> > 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.
>
> ____________________________________________________________
> TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5
> Capture screenshots, upload images, edit and send them to your friends
> through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST!
>
>
>

	[[alternative HTML version deleted]]

