[gradsusr] How can we write XDEF to open *.nc files?

[Jennifer Adams]

This file needs a PDEF entry, and narropen.gs will do all the work to create a working descriptor file for you. The only thing I would suggest is that you download the file and read it from your local disk instead of using a URL in your DSET entry and doing the I/O via opendap. The I/O for a pdef'd file via opendap is prohibitively slow. It is on my list of things to fix. 
--Jennifer


On Jan 20, 2014, at 1:02 PM, Hoop wrote:

> Charles Vanya,
> 
> The NARR data are on a Lambert Conformal Conic grid, not a regular
> lat-lon grid.  The good news is, there's a standard script for
> opening them.  It takes the arguments you give it, writes a
> Data Descriptor File (DDF) for the NARR data file, and then opens
> it with the "open" command.  The name of the script is "narropen",
> and, as I said, it's part of the standard suite of scripts.  It may
> be found at:
> 
> ftp://cola.gmu.edu/grads/scripts/narropen.gs
> 
> You can learn how to call it by running it without arguments.
> 
> -Hoop
> 
>> Date: Mon, 20 Jan 2014 03:07:34 -0800 (PST)
>> From: Charles Vanya <charles.vanya at yahoo.com>
>> Subject: [gradsusr] How can we write XDEF to open *.nc files?
>> To: "gradsusr at gradsusr.org" <gradsusr at gradsusr.org>
>> 
>> Dear All,
>> ?I am novel with GrADS and recently was doing a case study of a lightning
>> that killed 8 people at once and same place. As I was trying to load
>> cape.2013.nc and cin.2013.nc I encountered an error that I am failing to
>> resolve up to now. The error is shwon below:
>> =====================================================
>> 
>> ga-> sdfopen c:/Users/CHARLES/Downloads/cape.2013.nc
>> Scanning self-describing file:? c:/Users/CHARLES/Downloads/cape.2013.nc
>> gadsdf: SDF file has no discernable X coordinate.
>> ? To open this file with GrADS, use a descriptor file with an XDEF entry.
>> ? Documentation is at http://iges.org/grads/gadoc/SDFdescriptorfile.html
>> ga->?======================================
>> Now the question is how can I open such kind of data in Grads. I read
>> through the mentioned document but it is not helpful to me. Can any one
>> help me with guidance and set of commands to open and read this data?
>> the data is accessible from
>> http://www.esrl.noaa.gov/psd/thredds/fileServer/Datasets/NARR/monolevel/cin.2013.nc?
>> Thanks in advance
>> ?
>> Charles Langton Vanya
>> (Principal Meteorologist)
>> ---------------------------------------------------------------------------------
>> 
>> Department of Climate Change and Meteorological Services,
>> Regional Government Offices-(Next to Immigration Office),
>> Box 1808
>> Blantyre,Malawi
>> ---------------------------------------------------------------------------------
>> Tel:?? ??? (+ 265) 1 822 014
>> Cell: ??? (+265) 888 980 545 / 999 380 545
>> 
>> Fax:???? (+265) 1 822 215
>> ----------------------------------------------------------------------------------
>> 
>> "Tell me and I'll forget, show me and I may remember; involve me and I will understand"
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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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