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[IDV #LCA-261543]: GrADS .ctl files



> Hi Stefan-
> 
> Sorry for the delay in responding.  My real job takes priority.
> 
> > Such a legend doesn't exist in the version I am using(of I have it
> > turned off and I don't know how to turn it on). I am starting IDV just
> > by clicking the IDV application icon.
> 
> Sorry, if you click on the clock in the lower left corner of the main window, 
> the clock will switch to a memory monitor.
> 
> > Is there any documentation through Unidata that describes how each
> > derived quantity is calculated? This is especially important for
> > Equiv. Potential Temp, in which many different methods are used and
> > some are better than others.
> 
> Just the code (Mostly in ucar.unidata.data.grid.DerivedGridFactory). ;-)  In 
> most cases, IDV uses the brute force approach which does not account for 
> conservation of various parameters like GEMPAK or WRF post-processing code.  
> I would opt for having ARWPost calculate the variables you need most and use 
> those.  For Theta-E, the code looks like:
> 

Hi Stefan,
    This is the email we were discuss in the meeting, there maybe some 
confusion. But we need to do better document for these derived variables at 
some point.



Yuan

> return Util.clone(PotentialTemperature.create(pressure,
> AdiabaticEquivalentTemperature.create(temperature,
> mixingRatio)), getRealType());
> 
> which might give you a sense of how it is doing this.
> 
> Don
> 
> > On Apr 25, 2011, at 3:55 PM, Unidata IDV Support wrote:
> >
> > > Hi Stefan-
> > >
> > >> Been testing everything and all seems well so far. Only issue I am
> > >> getting is when editing derived quantities using the formula editor.
> > >> When I try to go plot a skew-t or another derived variable, I get a
> > >> Java
> > >> heap space error: java.lang.OutOfMemoryError: Java heap space. I am
> > >> only
> > >> trying to plot one time step using this derived quantity with edited
> > >> formula, so Im sure my machine isn't running out of memory(IDV is
> > >> allowed to use >1GB). I was able to successfully derived theta-e
> > >> using
> > >> the formula editor and plot one time step.
> > >
> > > I didn't have that issue on my system.  How much memory are you
> > > running the IDV with? (e.g. what does it show in the memory legend
> > > at the bottom of the screen.)  Also, how are you starting the IDV?
> > >
> > > Question: are all the
> > >> temperatures in the formula editors based off of temperature in
> > >> Celsius
> > >> or Kelvin? Thanks!
> > >
> > > Theoretically, it shouldn't matter.  The IDV will convert to Kelvin
> > > for the calculations.  If you find that the answers are not what you
> > > expect, let us know.
> > >
> > > Don
> > >
> > >> On Apr 21, 2011, at 2:45 PM, Unidata IDV Support wrote:
> > >>
> > >>> Hi Stefan-
> > >>>
> > >>> On 4/21/11 11:23 AM, Stefan Cecelski wrote:
> > >>>> I'll respond to both of your emails here.
> > >>>
> > >>> that's fine.  I'm using the official Unidata tracking system to
> > >>> document the solutions.
> > >>>
> > >>>> In response to the two concurrent open files:
> > >>>> The .ctl names are different, and access two totally different .dat
> > >>>> files with different file names. The multi-timestep .dat file is
> > >>>> 14.55GB. I also have other 1.33km horizontal resolution files at
> > >>>> 37GB
> > >>>> which I will be testing on. I will test to see if I select single
> > >>>> time
> > >>>> steps if it works. Maybe it has to do with opening too much data?
> > >>>
> > >>> Okay. The problem is that the pointers to the data that were beyong
> > >>> 2GB are larger than an integer can hold so it would end up as a
> > >>> negative number.  I made a change to use longs instead of ints.
> > >>>
> > >>> I updated the ncIdv.jar on RAMADDA, so please try that one.
> > >>>
> > >>>> In response to the derived variables:
> > >>>> Thanks very much, this clears it up. The attractiveness in using
> > >>>> IDV for
> > >>>> visualization is the fact that I don't have to script the code to
> > >>>> calculate such things as IPV, Skew-Ts, ect. In fact, I had to write
> > >>>> to
> > >>>> FORTRAN code to make ARWpost output for Equivalent Potential
> > >>>> Temperature. It is a SERIOUS pain in the butt, and would much
> > >>>> rather
> > >>>> just have IDV do it! I presume I can manually create functions that
> > >>>> will
> > >>>> select the right variables for derived quantities correct?
> > >>>
> > >>> Here's something you can do (and I didn't know you could do this
> > >>> until I tried ;-)).  From the IDV main menu, select Edit->Formulas-
> > >>>> Edit Formulas->Derived Quantities and then the formula you want to
> > >>> use (e.g. Sounding Data (%N1% & %N2% only)).  In the Formula Editor
> > >>> dialog, click on the Derived Tab. In the Parameters section, add in
> > >>> the parameters that you want on the line under TEMP, DEWPOINT.  I
> > >>> used tc,td.  Click the Change Formula button.  Then, if you have the
> > >>> data source already loaded, you can right click on it and select
> > >>> Reload Data from the pop-up menu, or you can load in a new data
> > >>> source if you didn't have one.  Now, under derived, you should see
> > >>> the old one and a new one that says Sounding Data (tc,td only) in
> > >>> the list (near the bottom).  If you want it near the top, just
> > >>> switch the order of the Parameter lines in the Formula Editor.
> > >>>
> > >>> You'll notice that the next time you go through the Edit->Formulas
> > >>> menu, the edited formula will be tagged with <local>.  You haven't
> > >>> overwritten the system one, just created a local version.  If you
> > >>> mess up, you can always delete that one (Remove Formula button in
> > >>> the Formula Editor) and start again.
> > >>>
> > >>> Don
> > >>>
> > >>>
> > >>> Ticket Details
> > >>> ===================
> > >>> Ticket ID: LCA-261543
> > >>> Department: Support IDV
> > >>> Priority: Normal
> > >>> Status: Open
> > >>>
> > >>
> > >>
> > >>
> > >
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: LCA-261543
> > > Department: Support IDV
> > > Priority: Normal
> > > Status: Open
> > >
> >
> >
> 


Ticket Details
===================
Ticket ID: LCA-261543
Department: Support IDV
Priority: Critical
Status: Closed


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