[R] Howto reduce number of ticks in X, Y axis while still containing all the data

[Dieter Menne]

Gundala Viswanath <gundalav <at> gmail.com> writes:

> I am trying to plot 100 x 100 matrix data in a level plot.
> The problem I have is that the x/y -axis label in ticks
> are jumbled together. Thus I want X/Y axis to contain
> 10 ticks only, yet still plotting all the 100 data.
> 
> Is there a way to do it?
> The code I have below doesn't work.
> 

Well, the code did not work because you did not provide example data
and forgot that levelplot is lattice, but when I add these two lines,
it works for me. Scaling is 20,40,..., and all point are shown (hope so, 
I did not count).

Dieter

library(lattice)
mat.data = matrix(rnorm(100*100),nrow=100)

# Corr contains 100x100 matrix
corr <- cor(t(mat.data), method ="pearson")

# Plot them
levelplot(corr, main="PCC of Top-100 Genes",
                xlab="Gene",
                ylab="Gene",
                scale=list(y=list(tick.number=10)) # Doesn't work
                )