spplot how to control variable scale with colorkey()
On 07/28/2010 12:31 PM, Paulo Eduardo Cardoso wrote:
While plotting with spplot, the legend space is reflecting the scale
of the variable.
eg, by dping something like this:
spplot(...,
colorkey = list(at = c(0, 5, 10, 20, 50,100), labels = c("0", "< 5",
"[5, 10)", "[10, 20)",
"[20, 50)", ">= 50"), space="bottom"))
spaces between each colour interval will be proportional to the scale
of this particular variable.
Can one control this, forcing a equal interval space to the legend at colorkey?
afaik, not without changing the values of the underlying map plotted.
You can of course first transform the map to a factor, using your legend
boundaries (and labels):
library(sp)
data(meuse.grid)
gridded(meuse.grid) = ~x+y
meuse.grid$distf = factor(findInterval
(meuse.grid$dist,c(0,0.1,0.25,1)),labels=c("0-0.1", "0.1-0.25", "0.25-1"))
spplot(meuse.grid["distf"],col.regions=bpy.colors(3))
Paulo
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