Unidata - To provide the data services, tools, and cyberinfrastructure leadership that advance Earth system science, enhance educational opportunities, and broaden participation. Unidata
         
  advanced  
 

Creation of large netCDF datasets using ncgen and CDL files

Hi-

I am attempting to create a netCDf file to store some model output, and am 
using a method that has worked for the past year. But now, the file I am 
creating is very large (3 Gb), and there seems to be a problem.

Here's my method:
I have a CDL file in which I define the extents of the domain and all the 
variables. I use the ncgen -o command to create a netCDF file based on the CDL 
file. To test the "goodness" of the file created, I use the ncdump -c command.

This method works well for me if I am creating datasets that are smaller than 
1.5 GB. However, I have just added more time step definitions to my CDL file, 
and while it creates the netCDF file seemlessly, the ncdump -c command returns 
an error.

I have even downloaded the latest version of the netCDf libraries 
(netcdf-3.5-beta) in hope that it would solve the problem, but I have had no 
luck.

I am puzzled, because if I modify the CDL file and decrease either the number 
of variables, or the size of the domain, the resulting netCDF file "works".

Below is the error message from the ncdump -c command. If you could enlighten 
me in any way on the matter, I would be most grateful. i would be glad to 
supply my CDL file (but didn't want to bother you with an attachement unless 
needed.) Thanks.

> ncdump -c OSU_YEAR_2D.nc
netcdf OSU_YEAR_2D {
dimensions:
        londot = 75 ;
        latdot = 50 ;
        loncrs = 75 ;
        latcrs = 50 ;
        levela = 23 ;
        levelb = 24 ;
        levelc = 1 ;
        time = 8760 ;
variables:
        float GROUNDT(time, levelc, latcrs, loncrs) ;
                GROUNDT:long_name = "GROUND TEMPERATURE" ;
(...)

        double time(time) ;
                time:time_origin = "01-JAN-1998:00:00:00" ;
                time:units = "seconds" ;
                time:point_spacing = "even" ;

// global attributes:
                :title = "OSU_YEAR SIMULATION OUTPUT" ;
data:

 londot = ncdump: Invalid argument
>


Frederic Chagnon        (617)253-5483
Ralph M. Parsons Laboratory    48-212
Massachusetts Institute of Technology
Cambridge         MA            02139








 
 
  Contact Us     Site Map     Search     Terms and Conditions     Privacy Policy     Participation Policy
 
National Science Foundation (NSF) UCAR Community Programs   Unidata is a member of the UCAR Community Programs, is managed by the University Corporation for Atmospheric Research, and is sponsored by the National Science Foundation.
P.O. Box 3000     Boulder, CO 80307-3000 USA     Tel: 303-497-8643     Fax: 303-497-8690