Hi !
I recently started to use the raster package to play with a file that I
consider fairly big. Since file size is subjective, following is the
summary output R gives of the data I am working with :
> wam
class : RasterLayer
filename : w001001.adf
nrow : 14143
ncol : 11733
ncell : 165939819
min value : 0
max value : 36.3769
projection : +proj=utm +zone=11 +ellps=GRS80 +datum=NAD83 +units=m
+no_defs +towgs84=0,0,0
xmin : 410133
xmax : 421866
ymin : 6287971
ymax : 6302114
xres : 1
yres : 1
I would like to aggregate the information of that RasterLayer. I tried
to use the function aggregate() without any real success. Following is
the code line I use to perform that procedure and the error message I get:
> wam<-aggregate(wam, fact=4, fun=mean, expand=FALSE, filename="wam_ag4")
Erreur : impossible d'allouer un vecteur de taille 633.0 Mo (A loose
translation would be : "Error: allocating a vector of 633.0 Mb in size
is impossible")
De plus : Messages d'avis :
1: In .local(x, ...) :
Reached total allocation of 3061Mb: see help(memory.size)
2: In .local(x, ...) :
Reached total allocation of 3061Mb: see help(memory.size)
3: In .local(x, ...) :
Reached total allocation of 3061Mb: see help(memory.size)
4: In .local(x, ...) :
Reached total allocation of 3061Mb: see help(memory.size)
I understood while reading help files and various posting that the
raster package can handle files larger than the RAM memory of the
computer. The computer I am using has 3Gb of RAM and the file I want to
read is only 633 Mb. I suppose there something I am not doing right.
Any help would be much appreciated !
Thank you in advance !
Guillaume Blanchet
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