In mdsumner/gdalextract: Demonstrate

Two inbuilt data files were created.

library(raster)

r <- raster(ncol = 32768, nrow = 21600)
r[] <- seq(ncell(r))

writeRaster(r, "extdata/tiled.tif", options = c("TILED=YES", "COMPRESS=NONE"))
writeRaster(r, "extdata/notile.tif", options = c("TILED=NO", "COMPRESS=NONE"))

writeRaster(r, "extdata/lzwtiled.tif", options = c("TILED=YES", "COMPRESS=LZW"))
writeRaster(r, "extdata/lzwnotile.tif", options = c("TILED=NO", "COMPRESS=LZW"))

library(raster)
x <- cbind(runif(10000), runif(10000))
tiled <- raster("extdata/tiled.tif")
notile <- raster("extdata/notile.tif")

system.time(extract(tiled, x))
system.time(extract(notile, x))

cll <- cellFromXY(tiled, x)

system.time(v1 <- rcg(tiled, cll, 1))
system.time(v2 <- rcg(notile, cll, 1))

mdsumner/gdalextract documentation built on May 22, 2019, 4:44 p.m.