[R]: (Lattice): Overlaying more than one trend surface using contourplot() and wireframe()

[Peter Ho]

Hi,

Is there a way to plot more than one trend surface using the functions 
contourplot() and wireframe(). I have found an add=T in contour(), but 
no equivalent argument in contourplot() and wireframe()?

I have taken the example 11-2 (pages 441-451) from Design and analysis 
of experiments (Montgomery  2001, 5th edition) to see if this could be 
done in R. I have managed to plot individual  contours for each response 
after using the surf.ls() and trmat() functions from the Spatial 
package, but have been unable to overlay the contours.   Ideally, it 
would be nice to also choose a different set of colours for shading the 
surface, so that when combing surfaces, we can immediately identify the 
optimum conditions. The final overlaid plot is shown on page 451 (Figure 
11-16) of the book.


Are there alternatve ways to also do this using other pakages ?

The R scipts for this examples can be found at the end of this email.

Thanks

Peter
..........................
################################################################################
g<- c(80,80,90,90,85,85,85,85,85,92.07,77.93,85,85)
h<- c(170,180,170,180,175,175,175,175,175,175,175,182.07,167.93)
Yield <- c(76.5,77.0,78.0,79.5,79.9,80.3,80.0,79.7,79.8,78.4,75.6,78.5,77.0)
viscosity <- c(62,60,66,59,72,69,68,70,71,68,71,58,57)
molwt <- 
c(2940,3470,3680,3890,3480,3200,3410,3290,3500,3360,3020,3630,3150)
###################################################################################
## Fit 2-order Polynomial trend for Yield
Yield.ls <- surf.ls(2, g, h, Yield)
trsurfY<- trmat(Yield.ls,min(g), max(g),min(h), max(h),100)
trsurfY[c("x","y")]<- expand.grid(x=trsurfY$x,y=trsurfY$y)
## Fit 2-order Polynomial trend for viscosity
viscosity.ls <- surf.ls(2, g, h, viscosity)
trsurfV<- trmat(viscosity.ls,min(g), max(g),min(h), max(h),100)
trsurfV[c("x","y")]<- expand.grid(x=trsurfV$x,y=trsurfV$y)
## Fit 1-order Polynomial trend for molecular weight
molwt.ls <- surf.ls(1, g, h, molwt)
trsurfMW<- trmat(molwt.ls,min(g), max(g),min(h), max(h),100)
trsurfMW[c("x","y")]<- expand.grid(x=trsurfMW$x,y=trsurfMW$y)
####################################################################################
### Contourplot for yield
contourplot(z ~ x*y, data = trsurfY,
          cuts = 10, region = TRUE,
          xlab = "Time",
          ylab = "Temperature",
          main = "yield",
          col.regions = trellis.par.get("regions")$col)
### Contourplot for viscosity
contourplot(z ~ x*y, data = trsurfV,
          cuts = 10, region = F,
          xlab = "Time",
          ylab = "Temperature",
          main = "yield",
          col.regions = trellis.par.get("regions")$col)
### Contourplot for molecular weight
contourplot(z ~ x*y, data = trsurfMW,
          cuts = 10, region = TRUE,
          xlab = "Time",
          ylab = "Temperature",
          main = "yield",
          col.regions = trellis.par.get("regions")$col)
##################################################################################