OPeNDAP is a means by which a user can access a remote file over the internet. There are certain caveats to using this functionality in NCL:
- The file must be located on a OPeNDAP server
- OPeNDAP works with addfile, addfiles, and isfilepresent.
Here's a test script you can use to see if your version of NCL has OPeNDAP capabilities:
;---Path to file served by OPeNDAP server at NOAA url = "http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/ncep.reanalysis.dailyavgs/pressure/" filename = "air.1948.nc" exists = isfilepresent(url+filename) if(.not.exists) then print("OPeNDAP test unsuccessful.") print("Either the file doesn't exist, or NCL does") print("not have OPeNDAP cabilities on this system.") else f = addfile(url + filename,"r") vnames = getfilevarnames(f) print(vnames) end if
Variable: vnames Type: string Total Size: 40 bytes 5 values Number of Dimensions: 1 Dimensions and sizes:  Coordinates: (0) level (1) lon (2) lat (3) time (4) air