[R-sig-Geo] contours in SpatialPixelsDataFrame

[Oscar Perpiñan]

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 Perpiñán Lamigueiro
Dpto. Ingeniería Eléctrica (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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