Re: [idvusers] time selection and area averages

Hi Suvarchal,
                 I probably didn't understand your area averaged correctly,
are you looking for something like: global averaged of surface temperature.
If so, you can certainly use the formula:

GridMath.applyFunctionOverLevels(S, GridMath.FUNC_AVERAGE)

and the input field S can be a temperature at the certain level. If you
want to average a specific region of your dataset, you can do the subset
first on the dataset property window.   To subset a certain time steps, you
probably want to do it in the dataset property window, it is very flexible
to do it this way than calling a formula.


Yuan



On Thu, May 28, 2015 at 5:16 PM, Suvarchal Kumar <
suvarchal.kumar@xxxxxxxxxxxxxxx> wrote:

>  Hi Yuan,
>                  Probably i am asking too much,
> I have seen getNthTimeGrid,  same as doing field.getSample(Nthtime),
> Actually I was wondering If i can subset a field(time|100,lat,lon) at
> select times , say at indices 2,40,30,90 as a new field, so that i could
> plot it as one variable/process it further. last resort for me would be
> declare a new field and use a loop setSample to create the new variable. It
> would be great to have some thing like pass array of time indices to a
> method to get all newtimes at once.
>
> i have tried rects(field.D=??) on a global field and with different
> smoothing Integers and I dont seem to get a global area averaged value, any
> example on a variable like field(time|100,lat|90,lon|180) would be helpful.
>
> Thanks,
> Suvarchal
>  ------------------------------
> *From:* Yuan Ho [yuanho@xxxxxxxx]
> *Sent:* Tuesday, May 26, 2015 8:08 PM
> *To:* Suvarchal Kumar
> *Cc:* idvusers@xxxxxxxxxxxxxxxx
> *Subject:* Re: [idvusers] time selection and area averages
>
>   Hi Suvarchal,
>            We have a few area average formulas available, such as
> rects(field, D=2) for the rectangular aperature smoothing,  and you can
> check out the Jython libraries under Grid Diagnostics. There is also a
> formula named getNthTimeGrid(field, Nth) for your second request under the
> Grid Routines.
>
>
>  Yuan
>
> On Mon, May 25, 2015 at 3:24 PM, Suvarchal Kumar <
> suvarchal.kumar@xxxxxxxxxxxxxxx> wrote:
>
>> Hi All, I am trying to write some jython scripts to make a composite
>> views,
>>
>> two things i cant figure out in my script:
>> 1) I want  to compute and display average of a grid at every time step.
>>
>> I feel there must be better way to do then loop around this to get an
>> Average
>> ucar.unidata.util.Misc.getAverage(avgvariable.getSample(i).getFloats()[0])
>> --well i can live with it.
>>
>> I am ok with an average but would like area average, i havent seen a
>> direct function(?), is there a way to get area of each grid box? that i
>> could multiply and average myself? I think i saw it somewhere  but cant
>> find where.
>>
>> 2) how to access a grid at particular time subset passed as an array?
>>   i have a gridded dataset with N times as timeset, would like to have
>> newvariables at time indices 1,2,7 or specified by time values, into a new
>> variable.
>>
>> so I would like to get  only a particular time subset of a grid specified
>> by a time array list(either index or value). This works as part of
>> Dataselection before reading dataset but cant manage it with a variable
>> after it is loaded?
>>
>> Cheers,
>> Suvarchal
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>>
>


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