Problem with GAM

Hi, 
I used GAM function with this code: 

library(mgcv)
modgam=gam(Z~X+Y,data=table)
vis.gam(modgam,view=c("X","Y"),plot.type="contour",zlim=c(1,16))

My problem is on my figure, the predicted values begin by 0 until 16 with an
interval equal 2:
1- I want that the predicted values (Z) begin by 1 until 16 with an interval
equal 1. I tried with zlim=c(1,16) but the result is not good. How do I do it?

Read ?vis.gam more carefully and note what is said about the `...`
argument for passing arguments on to, in this case, `contour()`. Take a
look at `?contour` and 

library(mgcv)
set.seed(0)
n<-200;sig2<-4
x0 <- runif(n, 0, 1);x1 <- runif(n, 0, 1)
x2 <- runif(n, 0, 1)
y<-x0^2+x1*x2 +runif(n,-0.3,0.3)
g<-gam(y~s(x0,x1,x2))

## compare default with user-selected levels:
layout(matrix(1:2, ncol = 2))
vis.gam(g, view=c("x1","x2"), plot.type="contour")
vis.gam(g, view=c("x1","x2"), plot.type="contour", levels = seq(0.35,
1.15, by = 0.1))
layout(1)

(Ignore the warnings)

2- On the figure, the red color corresponds with the weak values and light red
corresponds with the big values. How to invert the color to obtain red color
corresponding with the big values.

I think there is something else going on here - if you are displaying
the fitted model with +/- standard errors, which can't be done on a
contour plot - vis.gam issues a warning and switches to plotting via
`persp()`. If you meant change the colours on the `persp()` plot then I
think you are out of luck as the hi and lo colours are hard coded in the
function.

 
Note: I apologize
for my bad English
Thanks for your help.
Madou

HTH

G

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