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RE: plot & list the T & RH profile from gridded data


Johnson Space Center has a command that draws SKEWT diagrams from gridded
model data. Several issues, however:

1. The command is based on the "old" McIDAS SKEWT command, and does not have
   the correct thermal coordinates, ala UAPLOT. This is generally not that

2. The command is somewhat customized to work with gridfiles we construct
   outside of XCD-NOAAPORT, but I think it should work, as long as you have all
   the fields for a given forecast time in a single grid file.

3.  The command is not ADDE.  If you wanted to retrofit it, I would think
   UACROSS (from core McIDAS) has the logic you would need. In fact, the code
   in UACROSS is arguably more complicated than you would need for doing a
   single station "probe" of  a gridded dataset, so I'm not exactly sure why
   UAPLOT and UALIST have never been updated by SSEC to work on grid datasets.

Let me know if you are interested in our SKEWT-for-grids program.


Bryan Batson

>From address@hidden Fri Nov 15 13:13:54 2002


We have our version of  SKEWT-for-grids program that we also hacked
many years ago.  It kinda works, but ADDE would be much nicer.  I hope
someday the grid makes it into UALIST & UAPLOT.


>From address@hidden Fri Nov 15 17:53:59 2002
>CC: "'address@hidden'" <address@hidden>,
>   "HOETH, BRIAN R. (JSC)" <address@hidden>,
>   "'SUPUNIDATA'" <address@hidden>
>Subject: Re: plot & list the T & RH profile from gridded data

Hi Bryan,

Regarding #3 in your message below...
In a separate email I mentioned to Louis that when the UA* commands were
started, the goal was to first create UALIST and UAPLOT commands that
work with point/MD data so they'd be direct ADDE replacements for the
old UL, SKEWT and STUVE commands. Next, an XSECT replacement (UACROSS)
that works with grids as well as point/MD would be written. And after
that, the UALIST and UAPLOT commands would be retrofitted to work with

I was told that the retrofitting of UALIST and UAPLOT was supposed to be
relatively simple because the idea was to have UACROSS access the grid
server through VPSERV (which is also used by UALIST and UAPLOT).
However, the programmer coded UACROSS to bypass VPSERV and go directly
to the grid server. I was also told (and you've probably noticed) that
all of that programmer's sounding commands (UA* plus HODO and ALTIM)
were written in a fragile, inefficient, overly complicated and
nonstandard way. He's no longer here so we're left with code that's been
very difficult to maintain and enhance.

Therefore updating UALIST and UAPLOT to work with grids has become a
significant task. I believe it has been classified as a hold-funding
enhancement, meaning that it probably won't be done in the near future
unless a site steps forward and offers to pay for the changes.

If you don't mind sharing it with other sites, we would be interested in
putting your (or NASA-Langley's) SKEWT-for-grids program in McIDAS-XRD.
I'm not sure of the exact requirements, but if you're open to it going
into -XRD, let us know.

Barry Roth

>From address@hidden Fri Nov 15 18:54:46 2002

It shouldn't be a problem to donate our SKEWT-for-grids code.

If I might opine...I actually kind of like the notion of not using a
vertical profile server.  I think you are adding an unnecessary abstraction
by using that, and have another piece of code to maintain, plus more server
config issues.  When we implemented our forecast sounding SKEWT program in
ADDE (after first using DDE), it was actually a quite straightforward
conversion from the MD APIs.  Performance never seemed to be an issue. We
found that by sticking to the standard grid and MD ADDE servers, we actually
had less code to change, and I don't think we ever considered retrofitting
our forecast sounding SKEWT to use VPSERV.

Anyway...I guess there is a nice argument that if a lot of programs are
going to be "drilling" for vertical profiles, an abstraction is would be
helpful, but I would have done that on the client side, not create an
additional server.  

I'll check and see what I need to do to provide the source code.  


>From address@hidden Mon Nov 18 08:00:45 2002
>CC: "Batson, Bryan" <address@hidden>,
>   "HOETH, BRIAN R. (JSC)" <address@hidden>,
>   "'SUPUNIDATA'" <address@hidden>
>Subject: Re: plot & list the T & RH profile from gridded data


Sure, we can submit our version of SKEWT to XRD.  


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