Using GrADS to retrieve HYCOM data

Mark Hess mhess at OCEANI.COM
Wed May 6 15:13:15 EDT 2009


Success!  That was it.  A simple error on my part, of course.  I used gradsdap and it worked great.  Thanks so much to Kevin and everyone else who offered useful tips.

Mark

  ----- Original Message ----- 
  From: Kevin M Levey 
  To: GRADSUSR at LIST.CINECA.IT 
  Sent: Wednesday, May 06, 2009 10:32 AM
  Subject: Re: Using GrADS to retrieve HYCOM data


  Hi Mark,


  Make sure you are using GRADSDODS from the command line and NOT gradsnc or gradsc (GRads versions < 2) or simply "grads" using version 2


  Version 1.91: 


  I can open your file using gradsdods as follows:


  weather:fweather1 ~ > gradsdods


  Grid Analysis and Display System (GrADS) Version 1.9.0-rc1
  Copyright (c) 1988-2007 by Brian Doty and IGES 
  Center for Ocean-Land-Atmosphere Studies (COLA)
  Institute for Global Environment and Society (IGES)
  GrADS comes with ABSOLUTELY NO WARRANTY
  See file COPYRIGHT for more information


  Config: v1.9.0-rc1 32-bit little-endian readline sdf/xdf netcdf dap dap-stn lats athena printim


  Issue 'q config' command for more information.


  Landscape mode? (no for portrait):  
  GX Package Initialization: Size = 11 8.5 
  ga->  http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
  Unknown command: http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
  ga-> sdfopen http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
  Scanning self-describing file:  http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
  SDF file http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc is open as file 1
  LON set to 74.16 434.08 
  LAT set to -78.64 46.8781 
  LEV set to 0 0 
  Time values set: 2009:5:5:0 2009:5:5:0 
  ga-> 


  Not using gradsdods is a common mistake here.


  Using version 2.0


  weather:fweather1 /usr/local/grads2/Contents > ./grads


                Welcome to the OpenGrADS Bundle Distribution
                --------------------------------------------


  For additional information enter "grads --help".


  Starting "/usr/local/src/grads-2.0.a5.oga.4/Contents/Linux/Versions/2.0.a5.oga.4/x86_64/grads   " ...




  Grid Analysis and Display System (GrADS) Version 2.0.a5.oga.4
  Copyright (c) 1988-2008 by Brian Doty and the 
  Institute for Global Environment and Society (IGES)
  GrADS comes with ABSOLUTELY NO WARRANTY
  See file COPYRIGHT for more information


  Config: v2.0.a5.oga.4 little-endian readline printim grib2 netcdf hdf4-sds opendap-grids,stn athena geotiff
  Issue 'q config' command for more information.
  Loading User Defined Extensions table </usr/local/src/grads-2.0.a5.oga.4/Contents/Linux/Versions/2.0.a5.oga.4/x86_64/gex/udxt> ... ok.
  Landscape mode? ('n' for portrait):  
  GX Package Initialization: Size = 11 8.5 
  ga->  sdfopen  http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc   
  Scanning self-describing file:  http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
  SDF file http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc is open as file 1
  LON set to 74.16 434.08 
  LAT set to -78.64 46.8781 
  LEV set to 0 0 
  Time values set: 2009:5:5:0 2009:5:5:0 
  E set to 1 1 
  ga-> 


  As you can see, I can open your file just fine here too!


  Cheers
  Kevin


  On May 6, 2009, at 05/06/09 - 8:34 AM, Mark Hess wrote:


    Think I still must be doing something wrong and/or missing a few important concepts.  Here's what I get:

    ga-> sdfopen http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
    Scanning self-describing file:
    http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
    gaopnc error: nc_open failed to open file
    http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc
    read_metadata: gaopnc failed 
    gadsdf: Couldn't ingest SDF metadata.

    Perhaps I need to work on creating a .ctl file?  Any help with that is appreciated.

    Thanks,

    Mark



      ----- Original Message -----
      From: James T. Potemra
      To: GRADSUSR at LIST.CINECA.IT
      Sent: Tuesday, May 05, 2009 5:29 PM
      Subject: Re: Using GrADS to retrieve HYCOM data


      Hi Mark:

      Your variable constraints look more like Matlab syntax to me.  If you
      simply use sdfopen http://...... .nc (truncate
      everythins from the ? to the end) it should work.  You'll then have
      access to the entire data file and can just
      'set x 1500 2300', 'set y 1750 2169', and so on, then 'd mld'

      Jim

      Mark Hess wrote:
      > Can anyone tell me what I am doing wrong here?  At this point I'm just
      > trying to get a file off of the HYCOM server.  I used the server
      > http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc.html to
      > generate the URL string below, but am obviously missing something
      > quite basic (I'm an inexperienced GrADS user and brand new to
      > OPeNDAP). Will I need to create a custom .ctl file to access and
      > display these data or am I simply using the sdfopen command incorrectly?
      >
      > I am running GrADS version 2.0.a3.  My command and result are below.
      >
      > ga-> sdfopen
      > http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc?mld[0:1:0][1750:1:2169][1500:1:2300]
      >
      > Scanning self-describing file:
      > http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc?mld[0:1:0][1750:1:2169][1500:1:2300]
      > gaopnc error: nc_open failed to open file
      > http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/2d/rarchv.2009_125_00_2d.nc?mld[0:1:0][1750:1:2169][1500:1:2300]
      > read_metadata: gaopnc failed
      > gadsdf: Couldn't ingest SDF metadata.
      > ga->
      > Mark
      >
      >     ----- Original Message -----
      >     *From:* Dan Martin <mailto:Dan_Martin at BUOYWEATHER.COM>
      >     *To:* GRADSUSR at LIST.CINECA.IT <mailto:GRADSUSR at LIST.CINECA.IT>
      >     *Sent:* Thursday, April 30, 2009 7:40 PM
      >     *Subject:* Re: Using GrADS to retrieve HYCOM data
      >
      >     The full HYCOM data is on a curvilinear grid that I haven't been
      >     able to
      >     make work in grads. They set up a linear grid for grads users by
      >     cutting
      >     off pre-gridded section above 48 degrees north.
      >
      >     http://hycom.coaps.fsu.edu/opendap/nph-dods/datasets/hycom/global/GLBa0.08_rect/data/
      >
      >     The update schedule is a bit irregular and the server is not alway up,
      >     but nice data when it is there.
      >
      >     If anyone has the curvilinear grid version working in grads, any tips
      >     would be nice.
      >
      >     Dan
      >
      >     Mark Hess wrote:
      >     > Has anyone out there used GrADS to retrieve and display data
      >     from the
      >     > HYCOM OPeNDAP near real-time data server
      >     > http://hycom.coaps.fsu.edu/thredds/dodsC/glb_nrt_analysis.html?
      >     >
      >     > I am hoping to use GrADS to retrieve mixed layer depth data from
      >     this
      >     > server, but not real clear on the http/OPeNDAP string I would use to
      >     > download the file (whether it be ASCII or binary).  If you have done
      >     > this and could send a sample script or command showing the http
      >     > line that would be much appreciated.
      >     >
      >     > Thanks,
      >     >
      >     > Mark
      >     >
      >

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