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

Hi Brian-

> 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