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Matlab 2020b can't access GHRSST using OpenDAP url

PostPosted: Wed Apr 07, 2021 5:33 am
by wlzhong
Hi there,

I try to use the OpenDAP url to access the GHRSST data using Matlab (version 2020b). I use the following script as:

lon = ncread('https://podaac-opendap.jpl.nasa.gov/opendap/allData/ghrsst/data/GDS2/L4/GLOB/JPL/MUR/v4.1/2012/261/20120917090000-JPL-L4_GHRSST-SSTfnd-MUR-GLOB-v02.0-fv04.1.nc','lon');

I encounter the following message:
Error using netcdflib The NetCDF library encountered an error during execution of 'open' function - 'I/O failure (NC_EIO)'. If the data source was an OPeNDAP URL, see the OPeNDAP Troubleshooting section in the Users Guide.

Anyone have any idea of what happen?

Thanks!
WL

Re: Matlab 2020b can't access GHRSST using OpenDAP url

PostPosted: Thu Apr 08, 2021 11:38 am
by yiboj
Hi WL,
Thanks for your inquiry, please try using the following link: http://podaac-opendap.jpl.nasa.gov/open ... -fv04.1.nc, this maybe caused by some security issues.
Regards,
PODAAC DE

Re: Matlab 2020b can't access GHRSST using OpenDAP url

PostPosted: Fri Apr 09, 2021 6:20 am
by wlzhong
yiboj wrote:Hi WL,
Thanks for your inquiry, please try using the following link: http://podaac-opendap.jpl.nasa.gov/open ... -fv04.1.nc, this maybe caused by some security issues.
Regards,
PODAAC DE


Hi PODAAC DE,

Thank you for your reply. I changed the https to http but still it did not work out. Same error message as before. I used a VPN server to configure the Matlab internet connection.

Regards,
WL

Re: Matlab 2020b can't access GHRSST using OpenDAP url

PostPosted: Mon Apr 12, 2021 12:46 pm
by jwilkin
I just tested your command ...

>> lon = ncread('https://podaac-opendap.jpl.nasa.gov/opendap/allData/ghrsst/data/GDS2/L4/GLOB/JPL/MUR/v4.1/2012/261/20120917090000-JPL-L4_GHRSST-SSTfnd-MUR-GLOB-v02.0-fv04.1.nc','lon');


on my MacBook Pro with MATLAB 2020b and macOS Catalina and it works fine.

This is version '9.9.0.1467703 (R2020b)'

I did encounter some issues reading OPeNDAP from some PO.DAAC catalogs with versions 2019a, 2019b, and 2020a that were built with netCDF 4.6.1. With 2020b the version jumped to 4.7.3. Version 4.6 had issues with short timeouts.

You can check the netcdf version Matlab is using with the command
>> netcdf.inqLibVers


That might help debug the problem.

I received very helpful support from The Mathworks on my problem, so you might lodge a ticket with them if the problem is persisting.