Hi Don-
Don Morton wrote:
Hi, I'm pretty new to IDV and am just exploring the
capabilities. I've loved the idea that I can take my WRF
output files (netCDF or GRIB) and rapidly view the different
fields.
Glad this is working for you.
What I'm looking for - and I've found no indication that
this is possible - is to open multiple WRF output files (one per
timestep) and sequence through them - here's an example:
My current WRF output is set up to come out in netCDF files
at 3-hour intervals - one file for every three forecast hours (this
is necessary so that I can produce GRIB data for NWS AWIPS
in a real-time manner). What I'd "like" to be able to do, after
the WRF run is completed, is to start up IDV, open all of the
WRF output files as input, then sequence in time through a
specified field (e.g. 500mb heights) with a common perspective.
The only possible way to do this is to use an netCDF Markup Language
(NcML) file. However, I would need some sample files to
be able to create the NcML file. Could you place 3 files
from one run on an FTP server? Or, if you are daring, look
at the docs at:
http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html
and try to construct an NcML file using the JoinExisting option.
If I had all of my output data in a single file, this would be a
no-brainer, but I don't see an intuitive way to do this with IDV,
unless I'm willing to concatenate all my files into a single one,
then run IDV. I'm guessing that's what I'm going to have to do,
but if I've missed something and there's a better way, I'd sure
appreciate hearing about it.
One of the projects on the netCDF for Java development plate
is to do aggregations of multiple grib files since that is
how many people are storing their WRF output. For now, the
only solution is to concatenate the grib files together. There is
one caveat with that though. If you always use the same
file name for the concatenated file, you'll need to delete the
index file that is created. This index is in your home directory
under the .metapps/DefaultIdv/tmp/nj22 directory. It will have
a name that looks like the filepath to the concatentated file
with a .gbx extension. Currently, using NcML to aggregate
the grib files might not work.
Don
*************************************************************
Don Murray UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx P.O. Box 3000
(303) 497-8628 Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
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