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[McIDAS #MPZ-243939]: New NEXRAD Level III Radar products

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  • Subject: [McIDAS #MPZ-243939]: New NEXRAD Level III Radar products
  • Date: Wed, 05 May 2010 08:41:12 -0600
Hi Rick,

re:
> I'm trying to spin up on this radar stuff to see if we need any cal
> changes or if we can get away with just new color enhancements.

I don't think that any cal changes are needed.  Also, the need for new
color enhancements is a toss-up... the old ones are still valid.  The
usefulness for enhancements that have finer gradations of hues may
become obvious as we move into the convective season.

re:
> Yesterday I wanted to compare the new stuff with the old and needed to
> copy it down before processing.  Couple things I noted.

> The navigation
> is a little different for the upper left corner (maybe this is just the
> way it is).

Since the old and new images are being treated in the same manner on
the server side, I chalked this up to "just being the way that it is".

re:
> I don't have the exact echo/raw values, but any brightness
> values above 160 (as seen using imgdisp/imgprobe directly off the
> server) became zero on the local image that was copied from the server.

Hmm... that is very weird.  It is as though some value is being treated
as a signed char (values range from -128 - 128) instead of an unsigned char
(values range from 0-255).  I made specific changes in the server code to
take into account the need for the unsigned char range.  Your observation
that the values gotten directly from the server (e.g., IMGPROBE values) seem
to point to some assumed typing in the process that copies values to the
local dataset.  I will have to poke around to see where this could be
happening.

> Any clues why this would be happening.

I will review my server code (nexraget.cp) to make sure that there is not
some unintended unsigned char to signed char conversion going on.  I don't
think that there is since the values returned by IMGPROBE are OK.

More as I delve into the matter deeper...

Cheers,

Tom
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Ticket Details
===================
Ticket ID: MPZ-243939
Department: Support McIDAS
Priority: Normal
Status: Closed