contours in SpatialPixelsDataFrame

Hi,

spplot for SpatialPixelsDataFrame is built upon lattice::levelplot.
Thus, you can use most of its arguments in spplot. For your problem
you have to set "contour=TRUE" and "region=FALSE". Moreover, you can
customize the labels with (surprise!) "labels". This is documented in
the help page of lattice::panel.levelplot:

library(sp)
data(meuse.grid)
m <- SpatialPixelsDataFrame(points = meuse.grid[c("x", "y")],
    data = meuse.grid)

spplot(m["dist"],
       contour=TRUE, region=FALSE,
       labels=list(cex=0.6))

Best,

Oscar.
-----------------------------------------------------------------
Oscar Perpi??n Lamigueiro
Dpto. Ingenier?a El?ctrica (ETSIDI-UPM)
Grupo de Sistemas Fotovoltaicos (IES-UPM)
URL: http://oscarperpinan.github.io
Twitter: @oscarperpinan


2013/12/9 Agustin Lobo <alobolistas at gmail.com>:

I have a set of regularly distributed points (a grid) as a SpatialPoints DF.
In order to display the distribution of a continuos varaible in the data table,
I transform to SpatialPixelsDataFrame (using gridded(a) <- TRUE)
and after calculating the dimensions of the grid I use rasterize() to convert
to raster and then use rasterVIS::levelplot()

My question is, can equivalent contours be drawn directely on the
SpatialPixelsDataFrame object
to skip the tansform to raster?
I've tried with spplot(), but get filled intervals, not line contours.

Thanks

Agus

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