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[IDV #PUE-499201]: IDV 2.4b3: Problem plotting 3D isobaric surface using GFS GRIB2

Hi Dave-

When I said I thought I answered this before, I meant earlier
in the day.  I think I had it all set to send, but shut down
my browser before I hit send.  Looks like you only got one
copy. ;-)

> On Dec 13, 2007, at 3:24 PM, Unidata IDV Support wrote:
> >
> > Another approach is to use the 3D Surface->Color Shaded Plan View
> > over Topography
> > display.

> Thanks for reminding me about this--I couldn't remember what the
> alternative to the "3-D Pressure Surface" function was that you had
> build into the IDV. (Maybe that's what you were thinking had been
> covered in previous emails--it was.)
> 
> > When prompted for the topography field, select the geopotential height
> > again.  At present, you can't select one level, but you could reduce
> > the download
> > time by selecting two contiguous levels (e.g. 300 hPa and 350 hPa).
> > Be sure to select the same level range for the popup topography
> > field selector or you'll get an error.
> 
> I'm not sure what you mean by "can't select one level". I can select a
> single level when I select geopotential height as the field to view
> over topography, and I can select a single level when I specify
> geopotential height again when prompted for the Topography field. I
> can select the same, single level for both--I don't see anything about
> a range of levels.

Well, I guess I should have said that you can select only one level, but
it will be ignored and you'll end up with the entire grid.  However, you
can select 2 or more levels as a subset and those will be used. However,
there is a bug that the control shows all the levels and not just
the subset, so if you try to select a level not in what you selected,
you'll get missing data.

> Regardless of which level I choose, though, it always plots the 1000
> mb (100000 Pa) pressure surface, and I have to reset the level in the
> display control window to 300000 Pa (say), which then causes it redraw
> the display. 

This is because the single level is ignored and you get the entire
grid.  The nice thing though is that you can change levels. which
you can't really do with the other formula.

Moreover, in the display control window, the scroll bar
> on the Levels menu window doesn't work, so I can't scroll down to
> 300000 Pa--I have to enter the value in the Levels text box. (Using
> the up/down arrows next to the Levels text box seems to cause IDV to
> redraw the display for every intermediate value between the default
> 1000000 Pa value and the one I actually want (say, 3000000 Pa). This
> takes quite a while!

Yeah, I sort of noticed this.  I'll look into it.

> I've attached a bundle that loads the GFS GRIB 2 file and tries to
> plot a 300000 Pa pressure surface using 3-D Surface > Color-Filled
> Contour Plan View Over Topography, with 300000 Pa selected for both
> the geopotential height field both initially and for the Topography
> field. (It plots the 100000 Pa surface, where I've left it in the
> bundle.) At that point you  might see if you can replicate the problem
> with the Levels menu in the display control window.

Thanks for pointing this out. I'll look into it.

Don 

Ticket Details
===================
Ticket ID: PUE-499201
Department: Support IDV
Priority: Normal
Status: Open