20041022: IDV - simple difference

>From: "Bill Fingerhut" <address@hidden>
>Organization: Lyndon State College
>Keywords: 200410221641.i9MGfcSM027040  IDV resample

Hi Bill-

>Institution: lyndon state college
>Package Version: 1.1
>Operating System: os.name:Windows 2000; os.arch:x86; os.version:5.0; 
>Hardware Information: java.vendor:Sun Microsystems Inc.; java.version:1.4.2_01
> ; java.home:C:\\Program Files\\IDV_1.1\\jre; 
>Inquiry: An error has occurred:
>ControlDescriptor.Creating display
>org.python.core.PyException
>
>I want to display the difference between the current sea surface temperatures 
> and the 
>long term mean, using the IDV. 

Sounds like a reasonable thing to do. ;-)

>So,  I went to http://www.cdc.noaa.gov/cgi-bin/Composites/comp.pl  and retriev
> ed and 
>saved to disk a .nc file of mean SST values. I can read it and display the res
> ults in the 
>IDV just fine. Then, I chose the Latest SST Global .... model data set in the 
> data selector. 
>Thus, I have the desired two data sources, each can be displayed with the IDV

So far so good. 

>Next, I proceeded to use the formula, system -->  Simple difference a-b. I sel
> ected a
>and then b, and continued to create the display.

That's the right option.

>Unfortunately, an error occured (in part):

Bummer. ;-)

>  File "<string>", line 1, in ?
>java.lang.ArrayIndexOutOfBoundsException: 18048
>        at visad.FlatField.resample(FlatField.java:4557)
>        at visad.FlatField.binary(FlatField.java:1914)
>        at visad.FieldImpl.binary(FieldImpl.java:779)
>        at visad.DataImpl.binary(DataImpl.java:139)
>        at visad.DataImpl.subtract(DataImpl.java:192)
>        at visad.DataImpl.__sub__(DataImpl.java:1400)
>        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
>        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
>
>It would be nice if thef IDV could work with these two different datasets. ???

I just fixed a similar problem.  Could you try the following?

1) get the idv.jar at ftp://ftp.unidata.ucar.edu/pub/idv/untested
(note this is untested/unsupported code).

2) back up the existing idv.jar in your IDV_1.1 directory
(assuming you are using the InstallAnywhere version) and put
this new one in it's place.

3) Try your calculation again and see if it works.  If so, the
fix will be in the next release.  If not, let me know.

Don
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To:        "Fingerhut, William A" <address@hidden>
Subject:   20041024: IDV - simple difference 
From address@hidden  Mon Oct 25 07: 50:39 2004

>From: "Fingerhut, William A" <address@hidden>
>Organization: Lyndon State College
>Keywords: 200410221712.i9MHCRvV026294 IDV resampling

Hi Bill-
>Sorry, looks like the same error message.

Yup, I jumped the gun too quickly.  The problem is the same
that I was trying to (and did fix) for wind vectors from
different grids, but the other math functions will still fail
until we fix this in VisAD.  The problem occurs when the
math is done with a NEAREST_NEIGHBOR resampling, but not
with a WEIGHTED_AVERAGE.  The default with VisAD math functions
is NEAREST_NEIGHBOR, thus the error.  SSEC is working on 
this problem and when I have a fix, I'll give you another
JAR file to try.

Don