[gradsusr] cannot load CO-OPS Great Lake NetCDF datasets

Tue Sep 16 17:54:31 EDT 2014

Wow.  Cool beans.

I'm giving it a try.

Thanks,

Herb

From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org] On Behalf Of James T. Potemra
Sent: Tuesday, September 16, 2014 4:23 PM
To: GrADS Users Forum
Subject: Re: [gradsusr] cannot load CO-OPS Great Lake NetCDF datasets

Right, xdfopen.  Try the following (note this was made from ncdump of the file, and it approximates to constant latitude and longitude):
-----------
DSET   http://opendap.co-ops.nos.noaa.gov/thredds/dodsC/NOAA/LMOFS/MODELS/201409/glofs.lmofs.fields.nowcast.20140915.t19z.nc
TITLE  Example data file from CO-OPS
UNDEF  -99999
XDEF   nx     53 LINEAR -87.9721 0.0601
YDEF   ny    102 LINEAR  41.5845  0.0450
ZDEF   sigma  20 LEVELS   0.0000 0.0227 0.0454 0.0681 0.0908 0.1135 0.1362
     0.1589 0.1816 0.2043 0.2270 0.2724 0.3405 0.4313 0.5448 0.6810 0.7945
     0.8853 0.9534 1.0000
TDEF   time    1 LINEAR 00Z15SEP2014 24HR
VARS   11
lon=>long  0 x,y Longitude
lat=>lati  0 x,y Latitude
mask=>mask 0 x,y Land Mask
depth=>bathy 0 x,y Bathymetry
sigma=>sigma 20 z Sigma vertical coordinate
zeta=>zeta 0 x,y,t Free surface
air_u=>air_u 0 x,y,t Easward Air Velocity
air_v=>air_v 0 x,y,t Northward Air Velocity
u=>u   20 x,y,z,t Eastward Water Velocity
v=>v   20 x,y,z,t Northward Water Velocity
temp=>temp 20 x,y,z,t Temperature
ENDVARS
-----------
On 9/16/14 11:20 AM, Philbrick, Herb wrote:
Thanks, Jim.

I probably will need more details.  But, first I'll take a stab at a GrADS-like CTL file.  I presume xdfopen would be the GrADS command.

Thanks,

Herb

From: gradsusr-bounces at gradsusr.org<mailto:gradsusr-bounces at gradsusr.org> [mailto:gradsusr-bounces at gradsusr.org] On Behalf Of James T. Potemra
Sent: Tuesday, September 16, 2014 3:45 PM
To: GrADS Users Forum
Subject: Re: [gradsusr] cannot load CO-OPS Great Lake NetCDF datasets

Hi Herb,

You'll need to generate a data descriptor file for this.  Note that this model output
is on a rectilinear grid (lat/lon) and sigma-coordinate (vertical), so even with a
descriptor file you will need to make some approximations.  On the plus side you
should be able to use the template option to get time-series if needed.

Jim

Let me know if you need more details.
On 9/16/14 9:27 AM, Philbrick, Herb wrote:
Hello,

I would like to access CO-OPS Great Lakes Operational Forecast System, GLOFS, datasets using GrADS.

I have never worked with netcdf files.
Nor have I worked with a THREDDS server.
I often access NOMADS through its OpenDAP server using GrADS on my PC.  The GrADS command is like
                Sdfopen http://nomads.ncep.noaa.gov:9090/dods/rap/rap20140915/rap_00z

I have tried the following in GrADS (grads.exe - opendap enabled (see the PS))
        Sdfopen http://opendap.co-ops.nos.noaa.gov/thredds/wms/NOAA/LMOFS/MODELS/201409/glofs.lmofs.fields.nowcast.20140915.t19z.nc

GrADS returns the following message in the GrADS console:
Scanning self-describing file:  http://opendap.co-ops.nos.noaa.gov/thredds/dodsC
/NOAA/LMOFS/MODELS/201409/glofs.lmofs.fields.nowcast.20140915.t20z.nc
nc_open failure:
No such file or directory
http://opendap.co-ops.nos.noaa.gov/thredds/dodsC/NOAA/LMOFS/MODELS/201409/glofs.lmofs.fields.nowcast.20140915.t19z.nc does not exist or is not a netCDF file.

Couldn't ingest SDF metadata.
If this was an HDF-SDS file, try gradshdf.

I downloaded the nc file to my PC c:\grads19\win32\ sub-directory.
ga-> sdfopen glofs.lmofs.fields.nowcast.20140915.t19z.nc
Scanning self-describing file:  glofs.lmofs.fields.nowcast.20140915.t19z.nc
SDF file has no discernable X coordinate.
ga->

ncdump on the downloaded file DID obtain sensible information for header, variables values, etc.
The downloaded file can be loaded into Excel using the NetCDF add-in.
                Hence, the downloaded file sure seems to be good.

The folks at CO-OPS do not use GrADS and could not furnish advice.

Can you give me the proper command or settings to use to access LMOFS datasets?

Thanks in advance,

Herb Philbrick

PS

I am using Grads19 because, ultimately, I output grib-1 files.

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

Grid Analysis and Display System (GrADS) Version 1.9.0-rc1
Copyright (c) 1988-2005 by Brian Doty and IGES
Center for Ocean-Land-Atmosphere Studies (COLA)
Institute for Global Environment and Society (IGES)
This program is distributed WITHOUT ANY WARRANTY
See file COPYRIGHT for more information.

Built Fri Jan 25 02:30:31 EST 2008 for i686-pc-cygwin

This version of GrADS has been configured with the following options:

   o This is a 32-bit LITTLE ENDIAN machine version.
   o Command line editing (readline) ENABLED.
   o CIRES/CDC (http://www.cdc.noaa.gov) SDF/XDF interface ENABLED.
     Use sdfopen/xdfopen to read NetCDF files.
   o DTYPE netcdf is ENABLED; DTYPE hdfsds is DISABLED.
   o OPeNDAP (a.k.a. DODS) gridded data interface ENABLED. (http://opendap.org)
     This version is configured to access gridded data on OPeNDAP servers
     via the sdfopen or xdfopen commands, or using DTYPE netcdf.
   o OPeNDAP (a.k.a. DODS) station data interface (gadap) ENABLED.
     This version is configured to access station data on OPeNDAP servers
     via the open command.
   o PCMDI (http://www-pcmdi.llnl.gov) LATS interface ENABLED.
     This version is configured to write GRIB and NetCDF files.
   o DAO (http://dao.gsfc.nasa.gov) Athena Widget GUI ENABLED.
   o NRL/DAO/PCMDI XA or ImageMagick Image Output DISABLED.
   o printim command for direct png/gif output ENABLED.
     (via the GD Library -- http://www.boutell.com/gd)

For additional information please consult http://grads.iges.org/grads/

ga->

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