Read NetCDF file with read_stars in R

Question

I am trying to work with cordex climatic data (curvelinear and rotated data) in the stars package, and I am having a lot of issues, so decided to simply reproduce online example, and I fail reading in data with the command read_stars.

I am trying reproduce in this post https://github.com/r-spatial/stars/issues/52#issuecomment-430753055 by using the provided data here https://github.com/r-spatial/stars/issues/52#issuecomment-430548580

library(stars)
f = "1-RawData/example_ob_tran.nc" #path to the downloaded file

(r = read_stars(f))

When I do this I am getting

Error in CPL_read_gdal(as.character(x), as.character(options), as.character(driver), : file not found

while the file the following command works

(r = read_ncdf(f))

suggesting that the file exist.

This seems very basic, but I am unable to sort this myself. Does anyone see what I am doing wrong?

Answer 1

Always pay attention to the message appears on the console.

From your code,

library(stars)
f = "1-RawData/example_ob_tran.nc" #path to the downloaded file

(r = read_ncdf(f))

You would have seen this:

stars object with 3 dimensions and 1 attribute
attribute(s):
    tas [K]     
 Min.   :247.0  
 1st Qu.:267.4  
 Median :275.9  
 Mean   :274.5  
 3rd Qu.:282.6  
 Max.   :292.6  
dimension(s):
     from  to offset delta  refsys point                  values    
rlon    1 106     NA    NA      NA    NA  [106] -28.21,...,17.99 [x]
rlat    1 103     NA    NA      NA    NA  [103] -23.21,...,21.67 [y]
time    1   1     NA    NA POSIXct FALSE [1979-01-01,1979-02-01) 

As you see, it has tas attribute (variable). Now read the file again by defining var = "tas".

r = read_ncdf(f, var = "tas")

image(r, axes = TRUE)