benchmarking/benchmark_mask_rast.R

In IREA-CNR-MI/sprawl: sprawl: Spatial Processing (in) R: Advanced Workflows Library

in_rast     <- raster::stack(system.file("extdata", "sprawl_EVItest.tif", package = "sprawl.data"))
in_vect   <- read_vect(system.file("extdata","lc_polys.shp", package = "sprawl.data"), stringsAsFactors = T)
sp_polys <- as(in_vect, "Spatial")  %>%
  sp::spTransform(get_projstring(in_rast))


tmprast <- tempfile(fileext = ".tif")
in_rast <- build_testraster(1000, 1000, 5) %>%
  raster::writeRaster(filename = tmprast)
in_vect <- create_fishnet(in_rast, pix_for_cell = 200) %>%
  dplyr::sample_n(20)
in_vect <- sf::st_set_crs(in_vect, get_projstring(in_rast))
sp_polys <- as(in_vect, "Spatial")

bench <- microbenchmark::microbenchmark(
  "raster::mask" = {out_mask_raster  <- raster::mask(in_rast, sp_polys)},
  "sprawl::mask_rast" = {out_mask_raster  <- mask_rast(in_rast, in_vect, crop = FALSE)},
  times = 5)
boxplot(bench)

rast_dims <- c(500,1000,2000)
n_polys   <- c(1, 10, 100)
n_bands   <- c(1, 5, 10)
benches <- list()
index <- 0

for (dim in rast_dims) {

  for (polys in n_polys) {

    for (bands in n_bands) {

    message(dim, " ", polys, " ", bands )
    index <- index + 1
    tmprast <- tempfile(fileext = ".tif")
    in_rast <- build_testraster(dim, dim , bands) %>%
      raster::writeRaster(filename = tmprast, overwrite = T)

    in_vect <- create_fishnet(in_rast, pix_for_cell = dim/10) %>%
      dplyr::sample_n(polys)
    in_vect <- sf::st_set_crs(in_vect, get_projstring(in_rast))
    sp_polys <- as(in_vect, "Spatial")

    bench <- microbenchmark::microbenchmark(
      "raster::mask" = {out_mask_raster  <- raster::mask(in_rast, sp_polys)},
      "sprawl::mask_rast" = {out_mask_raster  <- mask_rast(in_rast, in_vect, crop = FALSE)},
      times = 1)
    bench <- summary(bench) %>%
      mutate(n_bands = bands, n_polys = polys, rast_dim = dim )
    benches[[index]] <- bench

    }

  }
}