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[ldmMcidas #FQZ-585386]: compress AREA



Hi Valentijn,

re:

>i'm o.k. You, how is the lodge in the mountains, finished everything?

It is a constant struggle to get the time to do some work on my house here
in the Colorado foothills (sigh)...

reL 'area2png' and its corresponding uncompressor is 'pnga2area'. 
> So i run them manually before we use the data?

'area2png' is used to convert an AREA file into a compressed version where
the headers are untouched, but the comment cards are moved to just after the
header.  The PNG-compressed image data then follows.  What we do for the IDD
UNIWISC datastream is:

- create an AREA of a sector for the datastream
- compress the AREA using 'area2png'
- insert the compressed AREA into the originating LDM product queue
- the end user receives the compessed AREA and uncompresses it using
  'pnga2area'

Uncompressing the image is not needed _if_ one only wants to look at the
headers.

> As you may remember we modified msgtaget2.for server to decompress the
> wavelet tranformed MSG HRIT segmented files on the fly,

Yes, I remember.

> so i could ask
> our programmer to do the same for the standard AREA ADDE server...

That would be _great_!

> I'm still running McIDAS X-2004, and i just updated msgtaget2.for from the 
> latest mcidas-v2005.

OK.  Can you send along your updated code for me to look at for inclusion in the
Unidata v2006 release?  Thanks in advance...

re: I need to make a new ldm-mcidas distribution
> O.k., can you make all related files available (incl. the ADDE server files),
> and tell us (me and Bas) where you would suggest building the PNG 
> decompression
> into the ADDE.

I can do this, but it will take some time as I am pressed to put together the
Unidata McIDAS release; incorporate new XCD stuff; and create documentation
for v2006.

> I recall we just called an external executable from the msgtaget2.for to do
> the MSG/HRIT decompression as the sources were bulky, but the PNG code maybe
> easier to port/ingest?

It would be "better" if the uncompression code was included in the inline
source.  It is also "better" (more efficient) if the server code can uncompress
the section of the image that was requested by the end user.

re: exchanges with Unidata being public/private
> sorry, this is a standard footer, please make it available to the mcidas
> group if you deem it useful....

Thanks!  Since we are a small group, we always want answers to user questions
made public so that the next person with the same question can answer
their inquiry by looking at our online archives.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: FQZ-585386
Department: Support ldm-mcidas
Priority: Normal
Status: Closed