Get ASCII grid from compressed .gz file from URL in R

Question

I am trying to download and gunzip grid files in ascii format, compressed to .gz files from an URL like this. I tried to get to the files via y <- gzon(url("name-of-url") and then gunzip(y), but for gunzip that is an invalid file. If I can decompress the file, I would like to read the .asc file with raster()

Any ideas how to solve this?

Answer 1

I don't know why unzip does not work on these files, but you can get at the contents as follows:

URL = "https://opendata.dwd.de/climate_environment/CDC/grids_germany/annual/summer_days/grids_germany_annual_summer_days_1951_17.asc.gz"
download.file(URL, "grids_germany_annual_summer_days_1951_17.asc.gz")

GZ = gzfile("grids_germany_annual_summer_days_1951_17.asc.gz")
Lines = readLines(GZ, 10)
writeLines(Lines, "grids_germany_annual_summer_days_1951_17.asc")

Now you have an ascii text file.