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[Support #LZX-581713]: color shaded image over topography

Hey Cory-

> Thanks Don....now I'm trying to place 10m HAGL wind barbs over topography. I 
> have to select a formula to calculate wind speed and direction and running to 
> trouble with surface winds. I can either plot 10m HAGL winds however, it is a 
> 2d plot where I can only raise and lower the image. The other is the True 
> wind vector formula, however, that only allows selection of constant pressure 
> surfaces (from the Gempak file)...not 10m HAGL. Is this feasible?

It's a little complicated, but will be easier in the next release.  For now:

- select the Misc->Any Field formula and the 3D Surface->Wind Barbs Over 
Topography and hit the Create Display button.
- when the topography dialog pops up, select geopotential height @ surface
- When the dialog pops up for "field", select the Grids->Make flow vectors from 
grid relative u and v data formula.
- Next, select the 2D grid->u-component of wind @ HAGL and 2D grid->v-component 
of wind @ HAGL
for u and v.

That will give you a plot.  A couple of caveats:

- it will not plot the vectors at 10 meters above the topography but right at 
the topography surface.  The 10 meters gets lost in the combination.
- The barbs are plotted horizontally at the location of the grid point.  If you 
underlay a topography, the barbs  will cut through the surface.  They don't end 
up draped over it.  Streamlines will end up on the surface.

> Next you guys should try to develop an app with IDV that allows users to kill 
> mosquitoes....man they are ferocious up here

Maybe we could put a 3D hand in the IDV. ;-)


> From: Unidata IDV Support address@hidden
> Sent: Tuesday, June 23, 2009 1:24 PM
> To: Joshua C Demko
> Cc: address@hidden
> Subject: [Support #LZX-581713]: color shaded image over topography
> Hi Cory-
> Best to send these to address@hidden in case I'm not around.
> > Real quick question? I am trying to remember the steps to drapping a color 
> > shaded image over topography. Here are my steps...
> >
> > Select temperature @ HAGL
> > Then under display select Color-Shaded image over topography under the 
> > display window...
> > Under the field selector I choose Formulas, then Miscellaneous, then Any 
> > Field hit OK
> > Then select 2d field (WRF gridded data) such as temperature
> >
> > Error dialog box pops up at that junction with the following error...
> >
> > topography units K must convertible with m or gpm
> > Now I am able to do this same procedure only for the model terrain but no 
> > other Met field. I believe I remember the steps correctly.  I am using IDV 
> > 2.7 beta 3.
> You need to select a topography (vertical units of m or gpm) for the 
> topography field.  You've already selected the temperature field in the first 
> step.  When the dialog pops up, select the 2D grid->geopotential height @ 
> surface (HGHT_NONE) field.  It should show up as a topography field now in 
> 2.7 b3 so you don't  have to use the Any Field any more.
> Don Murray
> Ticket Details
> ===================
> Ticket ID: LZX-581713
> Department: Support IDV
> Priority: Normal
> Status: Open

Ticket Details
Ticket ID: LZX-581713
Department: Support IDV
Priority: Normal
Status: Open

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