[R] lattice contourplot background covers inward-facing ticks

[Richard.Cotton at hsl.gov.uk]

> I wish to have inward-pointing ticks on my contourplot graph, but the 
> colored background produced by the "region=TRUE" statement covers the 
> ticks up, is there any way around this? Sample code below.  --Seth
> 
> library(lattice)
> 
> model <- function(a,b,c,d,e, f, X1,X2)          # provide model function 

> for contour plot
>  {J <- a + (b*X1) + (c*X2) + (d*X1*X2) + e*(X1^2) + f*(X2^2)
>   pp <- exp(J)/(1+exp(J))
>   return(pp)}
> 
> g <- expand.grid(X1= seq(0.3,0.9,0.001), X2 = seq(0.3,1, 0.001))
> g$z <- model(-29, -14, 52, 80, -3, -56, g$X1, g$X2)             # Create 

> variable z using gridded data, model, and variables
> 
> contourplot(z ~ X1 * X2, 
>  data = g,
>  region = TRUE,         # Adds color to background
>  cuts = 10,                     # Number of contour intervals...(and 
color 
> intervals!)
>  scales = list(tck = c(-1,-1))  # ticks go inward 
>  )   ### END

The easiest way is to make the contours semi-transparent by adding 
alpha.regions=0.7 (or whatever number you prefer) to the call to 
contourplot.  This has a couple of poosible disadvantages though:
1. It will change the colours you used
2. You can't print to some devices (windows metafile isn't supported)

Other solutions involve a lot of messing about.  You could manually draw 
ticks using grid.xaxis (and grid.yaxis) in the grid package, or stop 
plotting to the edges of the panel.

Regards,
Richie.

Mathematical Sciences Unit
HSL


------------------------------------------------------------------------
ATTENTION:

This message contains privileged and confidential inform...{{dropped:20}}