What is the recommended way to output a large byte GeoTiff image one
line at a time? I am creating large double and integer images using
writeRaster to create a GeoTiff file. I've been converting these to a
byte data type outside of R but it would be nice to R to output a byte
GeoTiff directly. I see there is a "type" flag for writeGDAL but I
haven't been able to tell if I can use that for line-by-line writing.
This is what I'm using now (thanks to feedback from Robert Hijmans and
possible unnecessary complications by me):
--
# Set output image properties
predrast <- setRaster(spot)
filename(predrast) <- outImage
nameVec <- colnames(trainvals)
cname <- nameVec[2]
for (n in 2:numbands) {
cname <- c(cname, nameVec[n+1])
}
# Use the randomForest object to predict land cover type based on the input
# image one line at a time
for (r in 1:nrow(spot)) {
spot <- readRow(spot, r)
rowvals <- values(spot, names=TRUE)
colnames(rowvals) <- cname
pred <- predict(randfor, rowvals)
pred <- as.numeric(pred)
predrast <- setValues(predrast, pred, r)
predrast <- writeRaster(predrast, format='GTiff', overwrite=TRUE)
}
--
Ned
_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
