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[IDV #WWB-790357]: simple difference on objective analyses



Hi Brian-

The tomorrow morning's build will have a fix for this.   Now, you can subtract 
in either order.  You can pick up the nightly build from:

http://www.unidata.ucar.edu/downloads/idv/nightly

This is 2.8 alpha 1.  We are planning a 2.8beta1 release next week if you want 
to wait.

One more thing off my plate. ;-)

Don

> > Thanks for identifying the problem. I tried flipping the order of the
> > lat/lon columns in the csv file for the obs, but that didn't change
> > things in the display.
> 
> No, it's the resulting grid that has the order at lon/lat and the vis5d grid 
> uses lat/lon.  I've needed to work on this for a while, so this is a good 
> reason to go down that scary path.  What it will mean is that instead of 
> doing a-b, you'll need to use sub(a,b).  I'll probably change the 
> simpleDifference to use that as well.
> 
> Don
> 
> > -----Original Message-----
> > From: Unidata IDV Support [mailto:address@hidden
> > Sent: Thursday, December 03, 2009 6:01 AM
> > To: Billings, Dr. Brian, Contractor, Code 7533
> > Cc: address@hidden; Billings, Dr. Brian, Contractor, Code
> > 7533
> > Subject: [IDV #WWB-790357]: simple difference on objective analyses
> >
> > Hi Brian-
> >
> > > Actually, I've noticed the same thing, but gridded-v5d isn't producing
> >
> > > a difference. It's just displaying the objective analysis of the
> > > gridded field; the same as you would get by just plotting the gridded
> > data.
> >
> > Thanks for pointing that out.  The problem is that one grid is in
> > lon,lat order and the other is lat,lon.  I'm working on a solution for
> > this.
> >
> > Don Murray
> >
> > > -----Original Message-----
> > > From: Unidata IDV Support [mailto:address@hidden
> > > Sent: Wednesday, December 02, 2009 9:21 AM
> > > To: Billings, Dr. Brian, Contractor, Code 7533
> > > Cc: address@hidden; Billings, Dr. Brian, Contractor,
> > > Code
> > > 7533
> > > Subject: [IDV #WWB-790357]: simple difference on objective analyses
> > >
> > > Hi Brian-
> > >
> > > > I've uploaded a zipped IDV bundle called simpledifference.zidv. The
> > > > comparison is between two precipitation fields. In this file, the
> > > > fields are unitless, but I have tried specifying mm in the text file
> >
> > > > header and using newUnit on the vis5d file and get the same result.
> > >
> > > Thanks for the files.  You definitely need to do the newUnit on the
> > > Vis5D data. I can get it to work if I subtract the v5d from the
> > > gridded point obs, but not the other way around.  I'll look into that
> > > further when I get into the office.
> > >
> > > Don
> > > > -----Original Message-----
> > > > From: Unidata IDV Support [mailto:address@hidden
> > > > Sent: Wednesday, December 02, 2009 3:52 AM
> > > > To: Billings, Dr. Brian, Contractor, Code 7533
> > > > Cc: address@hidden
> > > > Subject: [IDV #WWB-790357]: simple difference on objective analyses
> > > >
> > > > Hi Brian-
> > > >
> > > > > Full Name: Brian Billings
> > > > > Email Address: address@hidden
> > > > > Organization: Naval Research Laboratory Package Version: 2.7u2
> > > > > Operating System: Windows Vista
> > > > > Hardware:
> > > > > Description of problem: Have any issues been reported on using the
> > > > simple difference formula where one of the fields is an objective
> > > > analysis of point data? I have been trying to use this option on a
> > > > 2D vis5d file and a text data listing. The times are the same and
> > > > the units are the same, but the results are obviously incorrect. The
> >
> > > > users
> > >
> > > > guide says that the calculation is automatically performed only on
> > > > the
> > >
> > > > area in which the grids overlap, but this is not being done in my
> > > > output. Is the issue with using an objective analysis or some other
> > > possibility?
> > > > Thanks.
> > > >
> > > > If you are subtracting temperatures, the values will end up in K so
> > > > if
> > >
> > > > you convert to Celsius you'll be off by a factor of 273.  The IDV
> > > > does
> > >
> > > > not distinguish between delta degrees K and regular K so a
> > > > conversion between units will treat them as absolute.
> > > >
> > > > If that's not what you are seeing, could you upload the vis5d file
> > > > and
> > >
> > > > the text data to:
> > > >
> > > > http://motherlode.ucar.edu/repository/alias/idvupload
> > > >
> > > > so I can take a look.  Let me know what field you are trying this
> > > with.
> > > >
> > > > Don Murray
> > > > >
> > > > >
> > > >
> > > >
> > > > Ticket Details
> > > > ===================
> > > > Ticket ID: WWB-790357
> > > > Department: Support IDV
> > > > Priority: Normal
> > > > Status: Open
> > > >
> > > >
> > >
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: WWB-790357
> > > Department: Support IDV
> > > Priority: Normal
> > > Status: Open
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: WWB-790357
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> >
> 


Ticket Details
===================
Ticket ID: WWB-790357
Department: Support IDV
Priority: Normal
Status: Open


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