NETCDF descriptor file problem: gadsdf: SDF file does not have any non-coordinate variables.

[Kevin M Levey]

Hey Arlindo

Here is a weird thing - I figured out the problem.

According to the documentation: 

SDF_varname=>grads_varname
SDF_varname is the name the data variable was given when the SDF file was originally created. For NetCDF files, this name appears in the output from ncdump. It is important that SDF_varname exactly matches the variable name in the data file. SDF_varname may contain uppercase letters and non-alpha-numeric characters.


I had my names mixed, i.e. instead of

elevation=>alt 1 99 Altitude in meters

I had

alt=>elevation 1 99 Altitude in meters

hence the message "gadsdf: SDF file does not have any non-coordinate variables." I just wish there was a list of GRADS error messages and what they mean in the documentation. It would really help.

But the kicker is that for WRF outputted files it works the other way around.

Anyway, problem solved.

Thanks!

Cheers
Kevin


On Nov 18, 2009, at 11/18/09 - 11:15 AM, Arlindo da Silva wrote:

> Kevin,
> 
>   Could you make this file available to me for testing?
> 
>       Arlindo
> 
> 
> On Wed, Nov 18, 2009 at 10:27 AM, Kevin M Levey <klevey at customweather.com> wrote:
> Hi Arlindo,
> 
> No difference (same message) without the lat/lon variables listed in the CTL file and opening up directly with sdfopen: 
> 
> ga-> sdfopen /prod/custom/Input/modelplots/GRADS/reference/topo2.grd
> Scanning self-describing file:  /prod/custom/Input/modelplots/GRADS/reference/topo2.grd
> gadsdf: SDF file has no discernable X coordinate.
> 
> Cheers
> Kevin
> 
> On Nov 17, 2009, at 11/17/09 - 8:49 PM, Arlindo da Silva wrote:
> 
>> 
>> 
>> On Tue, Nov 17, 2009 at 10:52 PM, Kevin M Levey <klevey at customweather.com> wrote:
>> TUE 17NOV09: 1945PST
>> 
>> I am having problems opening trying to open a netcdf file of elevation data created by GMT. I am getting an error I've never seen before and don't understand.
>> 
>> The output from ncdump -h is:
>> 
>> netcdf topo2 {
>> dimensions:
>>        lat = 101 ;
>>        lon = 151 ;
>> variables:
>>        double lat(lat) ;
>>                lat:long_name = "latitude" ;
>>                lat:units = "degrees_north" ;
>>                lat:actual_range = 36.9, 37. ;
>>        double lon(lon) ;
>>                lon:long_name = "longitude" ;
>>                lon:units = "degrees_north" ;
>>                lon:actual_range = -120.18, -120.03 ;
>>        float elevation(lat, lon) ;
>>                elevation:long_name = "elevation" ;
>>                elevation:units = "meters" ;
>>                elevation:_FillValue = -999.f ;
>>                elevation:actual_range = 57.8879890441895, 96.9689636230469 ;
>> 
>> // global attributes:
>>                :Conventions = "COARDS/CF-1.0" ;
>>                :title = "../grids/madera/mapdata/topo/topo.grd" ;
>>                :history = "grdsample -R-120.18/-120.03/36.90/37 -I0.06m ../grids/DATA/tmp/madera_topo250.grd -G../grids/madera/mapdata/topo/topo.grd" ;
>>                :GMT_version = "4.5.0 [64-bit]" ;
>> }
>> 
>> 
>> My CTL file is as follows:
>> 
>> DSET /prod/custom/Input/modelplots/GRADS/reference/topo2.grd
>> TITLE This is a sample USL grid box for Central California
>> UNDEF -9999
>> XDEF lon 151 LINEAR -120.18 0.001
>> YDEF lat 101 LINEAR 36.9 0.001
>> VARS 3
>> alt=>elevation 1 99 Altitude in meters
>> lon=>lon 1 99 longitude
>> lat=>lat 1 99  Latitude
>> ENDVARS
>> 
>> 
>> Try eliminating lat/lon from the variable list; these are 1D coordinate variables:
>> 
>> VARS 1
>> alt=>elevation 1 99 Altitude in meters
>> ENDVARS
>> 
>> Better yet, have you tried opening this netcdf file directly with "sdfopen"?
>> 
>> ga-> sdfopen /prod/custom/Input/modelplots/GRADS/reference/topo2.grd
>> 
>>     Arlindo
>>  
>> However, here is the output I get when opening the CTL file (GRADS Version 2.0.a7.oga.2)
>> 
>> ga-> xdfopen usl_topo.ctl
>> Scanning Descriptor File:  usl_topo.ctl
>> SDF file has no discernable time coordinate -- using default values.
>> gadsdf: SDF file does not have any non-coordinate variables.
>> SDF Descriptor file usl_topo.ctl was not successfully opened & parsed.
>> 
>> Obviously I am doing something wrong here. I've had success before opening up WRF netcdf data files using this method, but if anyone has any suggestions here, I'd love to hear from you.
>> 
>> Thanks.
>> 
>> Regards,
>> 
>> Kevin M Levey, MSc in Oceans and Atmospheric Sciences (University of Cape Town)
>> Director of Meteorological Operations
>> CustomWeather, Inc.
>> San Francisco, California, USA
>> 
>> "Taking the World by Storm!"
>> 
>> http://www.customweather.com
>> http://www.myforecast.com
>> http://www.1stweather.com
>> 
>> cell: 415-794-0411
>> work: 415-777-3566
>> email: klevey at customweather.com
>> 
>> 
>> 
>> -- 
>> Arlindo da Silva
>> dasilva at alum.mit.edu
> 
> 
> 
> 
> -- 
> Arlindo da Silva
> dasilva at alum.mit.edu

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