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[IDV #JPX-707546]: IDV - caching data

Hi Bill-

> Institution: lyndon state college
> Package Version: 2.1
> Operating System: Windows 2000
> Hardware Information: Java: home: C:\\Program Files\\IDV_2.1\\jre version: 
> 1.5.0_06 j3d:1.3.2 fcs (build12)
> Inquiry: I have displayed 500 mb heights from the NAM and GFS at several 
> different forecast
> times. No problems.
> 
> Next, I want to subtract the GFS data from the NAM. So I used the system 
> formula to
> calculate a simple difference; for each field I point to the data already 
> present in the
> field selector. It appears as though data is being downloaded again even 
> though it
> should be cached ? (It is slow.)
> 
> Furthermore, the latter step seems to be downloading all levels despite the 
> fact that
> I originally restricted the data to just just 500 mb when defining the 
> display. I can imagine
> that this is possibly proper if the level choice only applies to the display 
> and not the data
> request ?

Currently, there is no way of specifying a level for a formula so it
used the entire volume.  Thus, it has to download it since you
only requested the 500 mb for the other displays.

> So I modified my proceedure to use 2 system formulas: one for simple 
> difference
> and one for selecting one level. That produced the result I want, but, seems 
> to be
> downloading the data again, even though it should be cached.

The slice at level first downloads the entire volume, then does the slice.

> So I added another step: I save the data from each model in the cache with 
> different
> names, and used them as inputs to the simple difference formula. This seemed
> to go okay, except that I can't see any contours of the difference field ? 
> The display
> control is created and everythin seems proper except nothing is added to the
> display window ?

As long as the models have the same projection and domain, this should
work.  However, if they are on different domains, there will be an error
when one 2D domain resampled to the other.   This is an area we need
to work on.

What do you have as a contour interval for your contours?  

> Today is not going well so far. Should I go home and go back to bed ?

Nah, tough it out. ;-)

Don


Ticket Details
===================
Ticket ID: JPX-707546
Department: Support IDV
Priority: Normal
Status: Open