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20000621: Unidata-Wisconsin datastream additions: CIMSS products (cont.)
- Subject: 20000621: Unidata-Wisconsin datastream additions: CIMSS products (cont.)
- Date: Wed, 21 Jun 2000 10:22:05 -0600
>From: "James D. Marco" <address@hidden>
>Organization: Cornell
>Keywords: 200006211552.e5LFqCT10971 Unidata-Wisconsin ldm-mcidas pnag2area
Jim,
> Yes, the conversion time is a bit rushed, but do-able for
>straight forward McIDAS users such as myself. The time frame
>doesn't permit enough testing before the semester starts, if you
>delay.
I agree.
>If the delta-formatted products remain available, then
>customized programs should still work, sans new stuff.
Yes, we could start broadcasting the same products in both PNG and delta
compressed formats, but I would much rather not do this.
I figured that essentially all folks out there were converting the UW
stream image products back into their native McIDAS AREA format; I
guess that I was wrong about at least one site. The other assumption
that I was making was that either pnga2area would work on a user's
system or it wouldn't. If it did, then the user would be in exactly
the same position as s/he was before. If it didn't, I would be here to
step in and help get it working. The addition of the CIMSS products
would give the sites some products _they are not dependent on_
that they could use to get the new decoding working.
>A thought (these are rare):
> Would it possible to modify a copy of the pnga2area decoder
> to produce an intermediate delta encoded file that could be
> piped back in to the local LDM data queue for decoding by
> the old tools? (Work for Unidata while users get ready for the
> new format.)
This could be done, but I think that it is time that would be better spent
getting sites up using the new compression.
>Goal:
> Allow unmodified customized programs to use the new format.
I think that NMIT might be using WXP's ability to read the delta
encoded image files directly (which I always considered a bad idea
since the delta encoding format was not guaranteed). If this is the
case, there shouldn't be a problem since WXP can also read AREA files
directly. All that would have to happen is the addition of the
decoding.
> Allow compression of the network feed to:
> Reduce network bandwidth
> Increase product availability
> Allow users time to perform the modifications to their
> locally customized programs, without slowing much needed
> upgrades to the data stream.
Good thinking. I will keep this in mind as a backup position.
>Downside: The local machine would spend more CPU cycles, and
> handle data twice, with a 'conversion' program running.
>
> Hence, any home-grown programs using the old format are
> eventually forced into rewrite, simply for efficiency.
Right.
> ...and, of course, "We'll get Tom to do it."
Hmm... :-o
Tom