[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[netCDF #IZF-303960]: about opening nc data

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [netCDF #IZF-303960]: about opening nc data
  • Date: Tue, 05 May 2009 06:14:02 -0600
Hi Tia,

> I have downloaded flux data from OAFlux Website but when I open this
> data in GrADS, it sais that there is no discernible x coordinate. I wonder
> what the problem is and check the data description which sais that the data
> is saved in "ncshort" format. Dose it mean that I need a special program to
> open it? And where can I find the utility?

According to the data description at

  ftp://ftp.whoi.edu/pub/science/oaflux/data_v3/readme-daily.txt

  All data files are in netCDF format and are compressed. 
  The flux and basic meteorological variables were saved by using
  "ncshort" format to minimize the size of the file. Land and missing
  values are 32766. All flux variables are multiplied by a factor of
  10, surface meterological variables by 100, and evaporation by 10.

The "ncshort" type is a 16-bit integer.  There are lots of utilities
for looking at netCDF data:

  http://www.unidata.ucar.edu/netcdf/software.html

One of the simplest is the "ncdump" utility that is part of every
netCDF installation, and just displays the metadata and data in a
simple text form.  Unless there are already special OAFlux utilities
for looking at the data, I recommend just using ncdump first, to
determine whether the data follows the recommended conventions for
packed netCDF data by using "scale_factor" and "add_offset" attributes
as described here:

  
http://www.unidata.ucar.edu/netcdf/docs/BestPractices.html#Packed%20Data%20Values

Hope this helps ...

--Russ


Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: IZF-303960
Department: Support netCDF
Priority: Normal
Status: Closed