[R] Contents of R-help digest.-contouring

[Spencer Graves]

Comments inline:

john lewis wrote:
> R- Users:
> 
> Can someone indicate what I am during wrong? This is a script essentially from 
> Venerable & Ripley's text on interpolating a surface with loess function but I can not get it to run.
> 
> Thanks.
> John Lewis
> Professor
> McGill University
> Montreal
> 
> library(MASS)
> library(modreg)
> data(topo)
> par(mfcol=c(2,2), pty="s")
> topo.loess <- loess(z ~ x * y, topo, degree=2, span = 0.25, normalize=F)
> topo.mar <- list(x = seq(0, 6.5, 0.1), y=seq(0, 6.5, 0.1))
> topo.lo <- predict(topo.loess, expand.grid(topo.mar), se=T)
> lo.1 <- as.data.frame(topo.lo)
> lo.2 <- as.matrix(lo.1$fit)

	  I just listed "lo.2":  It was a 4356 x 1 matrix;  in S-Plus 6.1, it 
was a NULL matrix with 0 rows and 1 column.  I recently attempted to 
upgrade to R 1.7.1 and now I can't get graphics from R.  However, the 
following worked for me in S-Plus 6.1:

   lo.2 <- matrix(topo.lo$fit, nrow=66)

With this, I got a plot that looked sensible (though I didn't compare it 
with MASS).

hope this helps.  spencer graves
> 
> lo.3 <- as.matrix(lo.1$se.fit)
> 
> contour(topo.mar$x,topo.mar$y,lo.2, levels = seq(700,1000,25),
> 
>         xlab="fit", ylab="")
> 
> points(topo)
> 
> contour(topo.mar$x,topo.mar$y,lo.3, levels = seq(5, 25, 5),
> 
>         xlab="standard error", ylab="")
> 
> title("Loess degree = 2")
> 
> points(topo)
> 
> 
> This is the error I keep getting.
> 
> "Error in contour.default(topo.mar$x, topo.mar$y, lo.2, levels = seq(700,  : 
>         no proper `z' matrix specified" 
> 
> I received this same message when I ran the script first without changing topo.lo
> from a list to data.frame etc. as seen below.
> 
> contour(topo.mar$x,topo.mar$y,topo.lo$fit, levels = seq(700,1000,25),
> 
>         xlab="fit", ylab="")
> 
> 
> I checked the length of each variable and they are correct.
> 	[[alternative HTML version deleted]]
> 
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