20050317: IDV sigma coordinates

>From: Marco Rodriguez <address@hidden>
>Organization: CIRA
>Keywords: 200503172038.j2HKcmv2013752 IDV sigma

Hi Marco-

>       Thanks for your prompt response. Also, wanted to take the opportunity
>to thank everybody at unidata for coding such a nice tool as the IDV,
>congrats!

Thanks for the feedback.  We're glad you find it useful.

>       Attached you will find the requested nc sample file with a Temperature
>field at 2 sigma levels (I made this up so one temperature field at one
>level is scaled by half with respect to the other). I have checked the
>file with a CF compliance checker and it seems ok. I can see the fields
>with ferret. Now, there are two things that I wanted to bring to your
>attention:
>
>1) With this file in version 1.2b1 of the IDV I am able to visualize the
>pressure at the surface (2D) and also lets me plot longitude and
>latitude fields. This seems to be gone in version 1.2b2. I am not able
>to visualize the pressure field anymore...what might be wrong? is this a
>bug in the new version?

Congrats, you've reported the first bug. ;-)  I'll look into this
next week, but I'm heading out of town tomorrow and won't be back
until Tuesday.  

>2) Neither version is able to visualize the Temperature field (as
>expected since sigma levels are not supported yet). My
>question/suggestion is: I would like to see the data on the other sigma
>layers and I do not care much about the "real" height or pressure from
>the surface. I know they are different for every point and maybe it
>should not be necessary for the software to calculate the pressure with
>the formula for sigma_p (give as many warnings to the user about this as
>you want). Think of it as plotting the next index in the vertical
>direction, with as many indexes as values defined for sigma in the nc
>file. I wonder if these fields could be plotted anyways with the
>indication of what level you are.

Thanks for the file, it'll be useful for testing.  Right now, the
IDV only supports mapping the vertical to altitude or pressure, so
we'll first get this working doing the transform.  However, plotting
the data with a generic vertical coordinate is on our list of things
to do, so consider your use case as another point of input

>I appreciate your dedication and please let me know of any
>updates/thoughts. Thanks

I'll let you know when we have something to test.

Thanks for the input.

Don
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