I have a bunch of .asc raster files that I need to access through Dropbox share links. For some reason I am unable to read the files into R. I have tried the raster(), read.csv(), and read.table() functions, but all return errors. R claims the files don't exist, while the Dropbox share links do in fact contain the .asc files. Any suggestions where I'm going wrong?
Error in .rasterObjectFromFile(x, band = band, objecttype = "RasterLayer", :
Cannot create a RasterLayer object from this file. (file does not exist)
My code
library(raster)
# define projection
RD_Proj4 = '+proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +units=m +towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812 +no_defs'
# The share link for the Dropbox .asc files
pm10 <- "https://www.dropbox.com/s/vkvbabwcwdk2r3q/conc_pm10_2019.asc?dl=0"
no2 <- "https://www.dropbox.com/s/foq2yufvi3694gt/conc_no2_2019.asc?dl=0"
# Trying to fetch the files from Dropbox
rasterData <- raster(pm10, crs = RD_Proj4)
@MrFlick pointed out what the right URL is, and with that you can do
library(raster)
RD_Proj4 = '+proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +units=m +towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812 +no_defs'
pm10 <- "https://www.dropbox.com/s/vkvbabwcwdk2r3q/conc_pm10_2019.asc?dl=1"
r <- raster(pm10, crs=RD_Proj4)
r
#class : RasterLayer
#dimensions : 320, 280, 89600 (nrow, ncol, ncell)
#resolution : 1000, 1000 (x, y)
#extent : 0, 280000, 3e+05, 620000 (xmin, xmax, ymin, ymax)
#crs : +proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812 +units=m +no_defs
#source : https://www.dropbox.com/s/vkvbabwcwdk2r3q/conc_pm10_2019.asc?dl=1
#names : conc_pm10_2019.asc.dl.1