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

[netCDFDecoders #KMK-502238]: Batch subset and convert from .grb to .nc

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 Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated.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: [netCDFDecoders #KMK-502238]: Batch subset and convert from .grb to .nc
  • Date: Wed, 29 Dec 2010 12:22:41 -0700
Hi David,

Instead of trying to create individual netcdf files, you can use NcML to 
extract only wanted variables and runTimes for a set of files in a directory. 
If you do in ToolsUI, then the ring tab will let you write out a netcdf file 
with all the aggregations.  Here's a sample NcML:

<?xml version="1.0" encoding="UTF-8"?>
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2"; 
enhance="true" >
  <attribute name="title" type="string" value="ForecastModelRun for all grb 
files"/>
  <aggregation dimName="run"  type="forecastModelRunCollection">
    <scan location="file:/local/robb/data/grib/nldas/" suffix="grb" 
dateFormatMark="NLDAS_MOS0125_H.A#yyyyMMdd.HHss" enhance="true" /> 
   
  
  <remove name="Evaporation" type="variable"/>
  ...
 ....
 </aggregation>
</netcdf>

Also look at:
http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/FmrcAggregation.html

If you read in a file into the NcML tab in ToolsUI, it gives a complete 
representation of a typical file. If a dimension, attribute, and variable is 
not in the NcML, it's  in the resulting file. When you read the NcML file in 
the ToolsUI viewer tab you should only get the results from the NcML There is a 
NcML tutorial that is worth looking at too. My test only included 2 files so 
the results was quick, it could be a time lag if there are many files. 

Robb...

Ticket Details
===================
Ticket ID: KMK-502238
Department: Support netCDF Decoders
Priority: Urgent
Status: Open