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[IDV #SWV-471189]: Wind vectors are not rotated when displayed

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  • Subject: [IDV #SWV-471189]: Wind vectors are not rotated when displayed
  • Date: Thu, 10 Apr 2008 08:55:14 -0600
Hi Bob-

> I'm a new user of IDV.  I just created a software package that writes my
> model output in grib2.  

That's a great step which will make your data more accessible to others.

IDV displays everything quite nicely except
> flowvectors.  I write my u and v components grid-relative but they are
> not rotated properly when I display vectors on the Map View.  The
> projection is polar stereo.  Is there a default setting for
> grid-relative u and v?

The Flow Vector derived parameter is whatever the winds are either
 grid relative or true.  So if your winds are grid relative, that's
how they should be plotted.  Is that what you are seeing?  For netCDF files, 
the flag of grid relative vs. true is saved as a variable and the
IDV used that.  For the grib files, it is stored differently and we do not 
yet use that information.  I'm looking into adding that now.

Until then, if you want true winds, you'll need to use the formula 
"Grids->Make flow vectors from grid relative u and v data".

Select the Formulas Data Source and then expand the Grids field
and find the "Make flow vectors from grid relative u and v data"
formula.  Select that and then pick the type of display you want.
When you click "Create Display", a dialog will pop up for you to
pick the U and V components.  You can subset the times and levels
for each parameter.

Tom Whittaker said he could help you with this when he returns
from Boulder.

Don Murray


Ticket Details
===================
Ticket ID: SWV-471189
Department: Support IDV
Priority: Normal
Status: Open