[R] problems with levelplot and contourplot

[Sundar Dorai-Raj]

Tom Lenaerts wrote:
> Hello,
> 
> 
> Using the following code i want to make a level or contourplot of some  
> data that I produced
> 
> library(grid);library(lattice);

No need to explicitly load "grid". This is done when attaching 
"lattice". Also, you do not need any ";" at the end of any lines.

> mydata <- read.table("avgee.dat");
> mymat <- as.matrix(mydata);
> mymat <-t(mymat)
> vals<-as.vector(mymat);
> conc<-c(0.0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5);
> a<- c(0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5,5.0,  
> 7.5,10, 25, 50, 75, 100);
> grid<-expand.grid(x=conc, y=a);
> levelplot(vals ~ conc * a, grid, region=TRUE, cuts=20);

Don't you mean

levelplot(vals ~ x * y, grid, region=TRUE, cuts=20)

Your data.frame "grid" has columns "x" and "y", not "conc" and "a".

> 
> When I do this get a blank output window and the following warnings
> 
> Warning messages:
> 1: longer object length
> 	is not a multiple of shorter object length in: is.na(x) | is.na(y)
> 2: longer object length
> 	is not a multiple of shorter object length in: id.na | is.na(var)
> 3: longer object length
> 	is not a multiple of shorter object length in: id & if  
> (is.shingle(var)) ((var >= levels(var)[[cond.current.level[i]]][1]) &
>  >
> 
> I've examined this mailinglist and the web and tried the examples other  
> people suggested.  They seem to work.
> Yet, my code seems the same as
> 
> a <-1:10
>   b <-11:20
>   j <- rnorm(100)
>   grid<-expand.grid(a = a, b = b)
>   levelplot(j~a*b, grid)
> 
> (from a previous mail)
> 
> 
> and it does not work.
> 
> Can anybody tell me what I'm doing wrong?  Furthermore as you ight  
> notice the data in a is in log-scale so I want the y-axis of the plot  
> in logscale.
> 

To print y in log-scale, add the following:

levelplot(..., scale = list(y = list(log = TRUE)))

HTH,

--sundar