Dear Nevil Amos,
Maybe the function 'reclassify' in the raster package is what you are
looking for.
Yours,
Lionel
On 13/09/2013 08:36, nevil amos wrote:
I have a large raster (4gb as a .asc file) with 197000 values, that I need
to reclassify by values in an large lookup table, 197,000rowsx80reclass
value columns.
I have tried using sub in a loop to replace the values, however the process
is taking hours, without even completing the first of the
reclassifications.
I would be grateful for any suggestions of processes that I can use to
speed the reclass process ( I need files that can be read back into ARCGIS
at the end of the process.
My current script is
library(raster)
r<-raster("Raster.asc")
COLS<-names(mydataOut[,5:88])
for (i in COLS){
subs(r,mydataOut,by="Value",which=i,filename=paste(i,".asc",sep=""))
print(paste ("done", i))
}
Many thanks
Nevil Amos
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