[R-sig-Geo] Rasters average

[Robert Hijmans]

>I'm trying to use MODIS 1day raster (.tif file) to obtain a, say, weekly 
>raster which is the average of the seven 1 day raster. 
>Using the following code (library raster) I can't obtain the results due to 
>computational limits. 

Luca, 

You can do something like:

s <- stack(paste("C:/MOD11A2/Confronto/1d00", 1:7, ".tif", sep=""))
fun <- function(x, ...) { x[x==0] <- NA; mean(x, na.rm=TRUE) }
m <- calc(s, fun)


I am not sure what you mean by "computational limits"; are you saying that
this takes a long time? If so, that would be  because you are looping over
cells. Avoid that, and things will be faster. 

Robert

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