Dear R users:

I have a dataset with two variables (>20000 observations, two samples from same subject) and I used "kernSur" from library(Genkern) to 
get a estimated bivariate density and corresponding plots as follows:

new.data.normal<-data.normal[!is.na(data.normal[,2]),]
x<-new.data.normal[,2]
y<-new.data.normal[,3]

op <- KernSur(x,y, xgridsize=50, ygridsize=50, correlation=0.4968023, 
              xbandwidth=1, ybandwidth=1)

#3D density plot
persp(op$xvals, op$yvals, op$zden,
        theta=30,phi=10,expand=0.5,ltheta=120,
        xlab="TECH3661.A",ylab="TECH3661.B",zlab="Prob",col="pink",
      , main="3D DENSITY PLOT-TECH3661 ", sub=" TECH3661.A AND TECH3661.B",
        box = T, axes = TRUE,ticktype = "detailed", )

#countour plot
image(op$xvals, op$yvals, op$zden, col=terrain.colors(100), axes=TRUE,xlab="TECH3661.A",ylab="TECH3661.B")
points(x,y,pch="*")
    
Now after above step, how can I use 'contour' or other commands to draw ellipse curves over above plots indicating "including about 68% data", "including about 84% data", etc. similar to the (-std,std), (-2*std,2*std),(-3*std, 3*std) intervals for univariate variable.

any suggestin will be appreciated.

liping








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