trying to use wget with opendap URL

[sbenson]

Hi,
Does anyone know why this isn't working? I get an empty merra.cdf file with 0 bytes.
wget -q -O merra.cdf "https://opendap.earthdata.nasa.gov/collections/C1276812851-GES_DISC/granules/M2T1NXRAD.5.12.4%3AMERRA2_400.tavg1_2d_rad_Nx.20180101.nc4.dap.nc4?dap4.ce=/SWTDN[0][94][524];/ALBEDO[0][94][524]"

I copied the raw Data URL from this page:
https://opendap.earthdata.nasa.gov/collections/C1276812851-GES_DISC/granules/M2T1NXRAD.5.12.4%3AMERRA2_400.tavg1_2d_rad_Nx.20180101.nc4.dmr.html

[GES DISC - alouise517]

Dear User,

The raw data url is most compatible when used in an internet browser. Please try using the "Copy encoded Data URL" option when using wget, curl, or any other command line tool.

For example here's the encoded data url for your request:
https://opendap.earthdata.nasa.gov/collections/C1276812851-GES_DISC/granules/M2T1NXRAD.5.12.4%253AMERRA2_400.tavg1_2d_rad_Nx.20180101.nc4.dap.nc4?dap4.ce=/SWTDN%5B0%5D%5B94%5D%5B524%5D;/ALBEDO%5B0%5D%5B94%5D%5B524%5D

We would recommend also using an Earthdata Token as described in the following documentation to avoid any issues with authentication when downloading data:

https://disc.gsfc.nasa.gov/information/howto?title=How%20to%20Access%20GES%20DISC%20Data%20Using%20wget%20and%20curl

Please give the following example a try, it should work as desired and save as a ~26kb .cdf file:

wget --header "Authorization: Bearer <token>" "https://opendap.earthdata.nasa.gov/collections/C1276812851-GES_DISC/granules/M2T1NXRAD.5.12.4%253AMERRA2_400.tavg1_2d_rad_Nx.20180101.nc4.dap.nc4?dap4.ce=/SWTDN%5B0%5D%5B94%5D%5B524%5D;/ALBEDO%5B0%5D%5B94%5D%5B524%5D" -O merra.cdf

Where <token> is your Earthdata Token from https://urs.earthdata.nasa.gov/ -> generate token.

Please note that data downloaded are in NetCDF-4 (.nc4) format even though the specified output file type you have included is a .cdf (Common Data Format).

If you have any other questions or require further assistance, please let us know.

Regards,
GES DISC User Services

[sbenson]

Thank you. That is very helpful. I have a .netrc file in my home directory with my earthdata login information. Is it better to use the "Token" instead of the .netrc for authorization?
Thanks,
Sally

[GES DISC - alouise517]

Hi Sally,

We would recommend using the EDL Token method we described, as it would work more universally with NASA's enterprise-level, Harmony data services.

Thanks, and please let us know if this helps or if you need further guidance.

Regards,
GES DISC User Services