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Re: Few questions...

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  • Subject: Re: Few questions...
  • Date: Wed, 06 Sep 2006 12:52:47 -0600
See below...

John Caron wrote:
>
>
> Rob Weingruber wrote:
>>    Hi John -
>>
>> Im back at it.....
>>
>> Ok, so after perusing GridDatatype andGridCoordSystem, I have a few
>> questions:
>>
>> 1. Can you explain the ensemble to me?  Is that for climatologies? 
>> (if so, i understand
>> the ensemble ;-).
>
> models are sometimes run several (many) times with slight variations
> of the input, these are called "ensemble" runs. The set of results
> then show the fuuture in a more statistically meaningful way. these
> results could be represented as an extra "ensemble" dimension.
>
> we havent yet tested this with any real world examples yet.
>
Got it. ;-)
>>
>> 2. Is the RunTime the same as what I termed the 'generate time'?  If
>> so, might be
>> better to use 'gen time' rather than run time, since a model run may
>> have a gen time
>> of 12Z, but it happens to be running at 12:18Z (my $0.02 ;-). 
>
> im not sure, i could also imagine the argument "a model run may have a
> runtime of 12Z, but it happens to be generated at 12:18Z".
>
> maybe we can have a bakeoff, i've also heard "analysis time".
True.  Any terminology works for me....
>>
>> Related to NCML:
>>
>> 3. Can I use the 'Forecast Model Run' yet?  If so, whudoIdo?
>
> we are just finishing the "Forecast Model Run Collection" (fmrc)
> aggregation, you can try it out if you want, but i havent written docs
> yet.  (there was an older "Forecast Model Run" aggregation which is
> now deprecated.)
>
> lets pick a simple dataset you want to do, and try serving it through
> the TDS:
>
>  1. have a look at the motherlode test server models
> (http://motherlode.ucar.edu:9080/thredds/idd/models.html)
>  2. install latest 3.13 development version of thredds.war (from
> http://www.unidata.ucar.edu/downloads/thredds/index.jsp)
>  3. pick a simple dataset, i will show you what the catalog should be.
>  4. ill try to get some docs written.
>
> now that ive said all this, maybe you just want to access the fmrc
> aggregation dataset from java code?
>
Im not quite ready for this.  I am working out our server issues at the
moment, meaning
that I am starting to fit this new gridded server stuff into one of our
existing server
infrastructures called Mantis (Aaron Braeckel's), which currently only
serves observations.
At the same time, I am thinking NCML, nj22, etc.  So a bit more
server/request/response work,
and I should be able to start using some NCML/nj22 to actually exec some
of those requests.

And yes, I think that I will want to specify the aggregations in NCML,
and then access
the various dimensions (runtimes, times, etc) from the Java code, via nj22.

;-)
>
>> 4. How can I aggregate with the 2D time coordinate?  I looked at the
>> joinExisting
>> doc
>> http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html,
>> and I still dunno what to do....
>
> its likely you need the fmrc aggregation.
>
SOunds likely ;-)

Smiles all around.  Gimme a bit more time, and we'll get together to discuss
where we're going...

;-)
>>
>> ;-)  Thanks John!
>
> yer welcome!