[Met_help] NetCDF format

John Halley Gotway johnhg at rap.ucar.edu
Wed Sep 9 20:12:32 MDT 2009


Holly,

I'm not familiar with "P&G".  What is that?  The projections currently
implemented in MET are lat/lon (i.e. Plate Carree), lambert conformal,
mercator, and polar stereographic.  Would one of those work for you guys?

John

> Thanks, John.  I really appreciate your feedback.  We will work on
> reformatting the file tomorrow.
>
> The projection we are working with is P&G.  One of my colleagues said he
> could try to remap it to Lambert Conformal, but that it would be easier
> to remap it to a pseudo-mercator grid.  Does MET support
> pseudo-mercator?  And if so, what are the global variables that we would
> need to specify for that projection?
>
> Thanks,
> Holly
>
> ___________________________________
> Holly C. Hassenzahl
> Meteorologist, Science Analyst
> Data Products Group
>
> Weather Central, Inc.
> 401 Charmany Drive Suite 200
> Madison, WI 53711
> +1.608.274.5789
> +1.608.276.4600
> http://www.weathercentral.tv
>
>
> -----Original Message-----
> From: John Halley Gotway [mailto:johnhg at rap.ucar.edu]
> Sent: Wednesday, September 09, 2009 3:40 PM
> To: Holly Hassenzahl
> Cc: met_help at ucar.edu
> Subject: Re: NetCDF format
>
> Holly,
>
> Sure thing.  Take a look in the directory METv2.0/out/pcp_combine for
> the
> output of the PCP-Combine tool.  These were generated in by the MET test
> scripts.  The NetCDF output from PCP-Combine is the format you should
> copy.
>
> The NetCDF format in METv2.0 is rather narrowly defined and wasn't
> originally intended for this sort of use.  We're working to provide more
> general support for NetCDF in the next release.
>
> But as long as you make it look like the output of PCP-Combine, you
> should
> be fine.  Here are a few pointers:
>
> - Be sure to name the NetCDF data variables using the GRIB code
> abbreviations listed in this table:
> http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html
>    - Any spaces in the abbreviation in that table should be removed in
> the
> variable name.
>    - For accumulation intervals, append the number of accumulation hours
> "_NN" to the variable name.  For example, 3-hours accumulated precip
> would be APCP_03.
>
> - Be sure to define all the variable attributes you see in the output of
> PCP-Combine.  The "_ut" means unix time, the number of seconds since Jan
> 1
> 1970.  FYI, the command "date +%s" will give you the current unix time.
>
> - Lastly, you need to define a bunch of global attributes that define
> the
> grid on which the data resides.  The PCP-Combine output gives an example
> of data on a Lambert Conformal grid.  If your data is on a different
> projection, you could email me for help.  Or you could find a Grib file
> that uses that type of projection, run it though PCP-Combine, and then
> look at the global attributes to see how they're defined.
>
> As I mentioned, we realize these conventions are overly restrictive.
> We're working to make it a lot easier to use NetCDF CF-convention data
> in
> future releases of MET.
>
> Thanks,
> John
>> Hello John-
>>
>>
>>
>> I hope this email finds you well.  We are hoping to convert one of our
>> in-house models into NetCDF format so it can be read by Point Stat in
>> MET.  Our first attempt gave us the following error:  "NetCDF:
>> Attribute not found."
>>
>>
>>
>> Is there a sample NetCDF file you could send me so we have something
> to
>> go off of?  Or a list of attributes/variables that must be defined in
>> the files in order to be read by MET?
>>
>>
>>
>> Thank you!
>>
>> Holly
>>
>>
>>
>> ___________________________________
>>
>> Holly C. Hassenzahl
>>
>> Meteorologist, Science Analyst
>>
>> Data Products Group
>>
>>
>>
>> Weather Central, Inc.
>>
>> 401 Charmany Drive Suite 200
>>
>> Madison, WI 53711
>>
>> +1.608.274.5789
>>
>> +1.608.276.4600
>>
>> http://www.weathercentral.tv
>>
>>
>>
>>
>>
>>
>
>
>




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