...well, it's Friday...
it's actually just
> brmax <- calc(br,max,na.rm=T)
> show(brmax)
class : RasterBrick
filename :
nlayers : 1
nrow : 5
ncol : 5
ncell : 25
projection : NA
min value : 248
max value : 248
extent : 0, 1, 0, 1 (xmin, xmax, ymin, ymax)
resolution : 0.2, 0.2 (x, y)
that simple.
Agus
2010/11/26 Agustin Lobo <alobolis...@gmail.com>:
> Hi!
>
> Given a brick object (longitude, latitude, time), I need a (lon,lat)
> layer with the maximum value of each cell across time.
> That's the equivalent to
>> x = array(round(runif(n=3*4*5,min=0,max=10)),dim=c(3,4,5))
>> apply(x,c(1,2),max,na.rm=T)
>
> but for x being a brick object. How can I do it with raster?
>
> I've tried
>
>> funmax <- function(x) {apply(x,c(1,2),max,na.rm=T)}
>> show(br)
> class : RasterBrick
> filename :
> nlayers : 3
> nrow : 5
> ncol : 5
> ncell : 25
> projection : NA
> min value : ? ? ?
> max value : ? ? ?
> extent : 0, 1, 0, 1 (xmin, xmax, ymin, ymax)
> resolution : 0.2, 0.2 (x, y)
>> brmax <- calc(br,funmax)
>
> But the result is wrong, as it should be 1 layer and not 3:
>> show(brmax)
> class : RasterBrick
> filename :
> nlayers : 3
> nrow : 5
> ncol : 5
> ncell : 25
> projection : NA
> min value : 232 232 248
> max value : 248 248 248
> extent : 0, 1, 0, 1 (xmin, xmax, ymin, ymax)
> resolution : 0.2, 0.2 (x, y)
>
> I've also tried with stackApply(), but do not think that's the way to go.
> Also, I'm concerned that apply() is typically very slow in R, and I'm
> dealing with a large brick object.
>
> Thanks
>
> Agus
>
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