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
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