I have a global raster at 0.0833 degree resolution which covers both land and ocean. I am trying to extract raster only for the land areas. The way I am doing is to use a global shapefile and use it as a mask. However, this is taking ages (more than 2 hours and still not done) and wondered if there's anything fundamentally wrong I am doing
library(raster)
# this is my raster
class : RasterLayer
dimensions : 4320, 10800, 46656000 (nrow, ncol, ncell)
resolution : 0.008333333, 0.008333333 (x, y)
extent : -180, -90, -90, -54 (xmin, xmax, ymin, ymax)
crs : +proj=longlat +datum=WGS84 +no_defs
source : 1_High_2050_.tif
names : X1_High_2050_
values : 3, 3 (min, max)
# my shapefile
library(maptools)
data('wrld_simpl')
# my approach
mask_raster <- mask(temp_rast, wrld_simpl)
This is much faster with the terra package (the replacement for raster)
library(terra)
r <- rast(res=1/120, xmax=-90, ymax=-54)
r <- init(r, "cell")
library(geodata)
w <- world(path=".")
system.time(x <- mask(r, w))
# user system elapsed
# 1.36 0.53 1.89