[gradsusr] Accessing data chunks via GrADS data server

[Jennifer Adams]

On May 27, 2014, at 8:45 PM, Marsh, Kieren [FGUAE] wrote:

> Can someone please explain to me how the bracketed notation works to extract data from a GDS. By this I mean the following:
>  
> http://metserver:9090/dods/neww3/neww3.00z.ascii?htsgwsfc[0:20][0:40][110][72]
>  
> which extracts htsgwsfc over ensemble members 1-21 (0-20 when zero based), time values 0-40 at x=110 and y=72 and gives an ascii text file I can grab using something like wget.
>  
> Am I able to use this kind of notation in GrADS scripts to access a chunk of data that I can define to a variable?
>  
> e.g.
>  
> 'define myvar = http://metserver:9090/dods/neww3/neww3.00z.?htsgwsfc[0:20][0:40][110][72]'
>  
> All combinations I try don't work and I can't find any documentation on it.

The way to do this is to open the URL, then set the dimension environment in GrADS, then define your variable. 
Something like this:

'sdfopen http://metserver:9090/dods/neww3/neww3.00z'
'set e 1 21'
'set t 1 41'
'set x 110'
'set y 72'
'myvar=htsgwsfc'

--Jennifer


>  
> I have looked at the documentation for access using the curly bracket notation, e.g.:
> http://metserver:9090/dods/_expr_{neww3/neww3.t00z}{htsgwsfc}{73:73,111:111,1:1,00Z20MAY2014:00Z25MAY2014}
>  
> ...but I don't seem to be able to capture the ensemble dimension using this format.
>  
> Any help will be greatly appreciated.
>  
> Kieren
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--
Jennifer M. Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
111 Research Hall, Mail Stop 2B3
George Mason University
4400 University Drive
Fairfax, VA 22030 





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