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

Hi Brian-

> Okay, I got it to work by defining a formula with sub() and newUnit().
> No luck with simple difference, but I can manage this way. Look forward
> to the full 2.8 release.

Sorry for the confusion.   Yes, you'll need  the newUnit and to use sub.  In 
general, I suggest using the functions sub, add, mul and quo instead of -,+,* 
and /.  The functions handle 2D vs. 3D slices, lat/lon incompatibilies (at 
least now) and other issues that we have given the myriad data formats we 
support.

I don't think I'll change simpleDifference until the 2.9 release because that 
would require more testing and doc changes.

Don

> -----Original Message-----
> From: Unidata IDV Support [mailto:address@hidden]
> Sent: Friday, December 04, 2009 10:00 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 downloaded this morning's build, but got the same result. I tried
> > both the simple difference option and sub(a,b), but everything gives
> > me the same plot.
> 
> Hmm, I just ran with the nightly build and it worked.  I've attached a
> bundle with the result.  Are you sure you got the nightly and not the
> regular build?  Could you check the Help->About dialog to see the
> version and build date?
> 
> > On a side note, is the gain in the objective analysis going away for
> > good? I liked being able to match the observations more exactly. On
> > the other hand, I love the new smoothing option on color-shaded plots.
> 
> It's just that the panel doesn't expand to show it.  If you make the
> Field Selector taller, it should appear.  The smoothing option has
> always been there on color shaded plan views, but maybe you were using
> the Image Display instead which doesn't have that.
> In either case, I'm glad we got something right for you. ;-)
> 
> Don
> 
> > -----Original Message-----
> > From: Unidata IDV Support [mailto:address@hidden]
> > Sent: Thursday, December 03, 2009 2:58 PM
> > 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-
> >
> > 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
> >
> >
> 
> 
> 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