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[IDV #DZF-714003]: MERRA-2 opendap access



> Hello IDV gurus,
> 
> I would like to be able to access MERRA-2 data via opendap.
> 
> I have followed the guidelines given in this thread:
> 
> https://www.unidata.ucar.edu/mailing_lists/archives/idvusers/2017/msg00001.html
> 
> and opened the following file in the catalogs section:
> 
> https://goldsmr5.gesdisc.eosdis.nasa.gov/opendap/MERRA2/M2I3NPASM.5.12.4/catalog.xml
> 
> However, when I do the above, I am limited to access only the times
> given per individual .nc file. I would prefer to be able to select times
> across multiple .nc files from the times section in the field selector
> tab. Essentially, each .nc file is opened as an individual data source
> whereas I would prefer to have all .nc files concatenated in time so
> that I can select across all times in the field selector.

Hi Teddy,

Good to hear from you, it has been a while.

You should be able to select multiple files from the Data Chooser > Catalog, 
you can open
each tree, and select what you want with the shift key or ctrl key. The 
important thing is
to specify the "Data Source Type" as "Aggregate Grids by Time", then Add 
source,.....

It would be nice if you can provide more information of IDV usage in the 
Caribbean region. I would
love to provide any help you needed.

Sorry for a little delay as I was traveling in the Thanksgiving break.


Yuan
> 
> The alternative is to use the URL option in the Data Choosers tab. I can
> access MERRA-2 across all times when I enter the below address in the URL
> option:
> 
> dods://goldsmr4.gesdisc.eosdis.nasa.gov/dods/M2I1NXASM
> 
> But there is a lag between most recent data and what is available from the
> URL address. The catalog option has almost no lag in data availability. Is
> there a way to read in the catalog file so that all times can be selected
> in a similar way to time selection for the URL section so that I can
> acce ss most recent data across multiple .nc files?
> 
> A more general question is, what is the difference
> (advantages/disadvantages) between data access through URL or Catalog?

URL is a individual file (at least logically) and the Catalog is the pointer to 
multiple files in 
the server.
> 
> I hope all is well. We continue to use the IDV in training and classes in
> the Caribbean. I have integrated the IDV into training at The Caribbean
> Institute for Meteorology and Hydrology and even use it for class work at
> The University of the West Indies. It is always very well received. Keep
> up the great work.
> 
> Thank you,teddy
> 
> http://www.teddyallen.com
> 
> "To move quickly, go alone. To move far, go together."
> 
> African Proverb
> 
> 
> 


Ticket Details
===================
Ticket ID: DZF-714003
Department: Support IDV
Priority: Normal
Status: Open
===================
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