[R] Re: date axes and formats in levelplot

Deepayan Sarkar deepayan at stat.wisc.edu
Tue Aug 10 16:19:07 CEST 2004


On Tuesday 10 August 2004 01:34, Toby.Patterson at csiro.au wrote:
> Hi all (and particularly Deepayan),
>
> A while back Deepayan helped me with the query in the text below
> (thanks again). Specifically it was about changing the way that dates
> plotted on the axes of lattice plots.
>
> While this works using xyplot, everything comes apart when I use
> levelplot. The axis labels on the date axis are shown as the integer
> representation of the date (number of seconds since the origin I
> assume). I guess that the POSIX dates are getting coerced into
> numeric objects somewhere along the way and that there is no easy fix
> for this.

You are right. At first glance, it appears that I have been negligent in 
properly updating the default prepanel function for levelplot to handle 
DateTime objects. For now, you could use xyplot's default instead: 

levelplot(z ~ x * y, 
          prepanel = lattice:::prepanel.default.xyplot)

Add a 'scales = list(axs = "i")' to get a better looking result (with 
the bordering rectangles partially clipped).

Deepayan




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