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[Support #HWT-941133]: FW: [Fwd: McIDAS AREA files with PNG compression III]



Hi Tyn and Bas,

I hope you are well and enjoying the winter season.  I continue to get snow
at my house here in the foothills of the Rockies above Boulder, Colorado.
So far, I have received over 1.2 m of snow at my house!

Now, down to business:

Late last week and this past weekend I got serious about adding direct
support for Unidata PNG-compressed images (both AREA and GINI) in McIDAS.
The results of my effort are included in the gzipped tar file, mcupdate.tar.gz,
that is attached to this note

In order to implement the changes that I made, you need to do the following
on the Linux workstation on which McIDAS-X v2006 is installed:

<login as 'mcidas'>
cd ~mcidas/mcidas2006/update
-- copy the file that is attached, mcupdate.tar.gz, to this directory
./mcunpack
cd ../src
make
make install

NB:

- it would be a _good_ idea if you backed up the files that will be replaced
  before running mcunpack from the ~mcidas/mcidas2006/update directory.  Here
  is the list of files that will be overwritten:

  in ~mcidas/mcidas2006/src:

  CHANGES.2006
  giniutil.c
  giniutil.h
  icget.for
  ispnghed_.c
  makefile
  rdtrka.for

  in ~mcidas/mcidas2006/data:

  VERSION.TXT

- the updates are for the v2006 McIDAS distribution.  Attempting to use
  them with any other version will have unknown results, but my feeling
  is that they would be _bad_

Bas,

As you will see, I chose to _not_ modify mcread.c since it is _the_ general
purpose file reading program in McIDAS.  Instead, I created a new C file,
arealine.c, that will check the type of the image to be read to determine
if it is a PNG-compressed image.  If it is not, it simply calls Mcread in
the same way that lbi_ does.  'arealine' is called from the Fortran routine
'rdtrka' (located in rdtrka.for); it replaces the call that 'rdtrka' made to
'lbi_'.

The change made to get the audit trail listing from IMGLIST (keyword sequence
FORM=AUDIT) was much simplier, but it still required that one image file read
be made from 'icget' (in icget.for) to determine if it the image in question
is PNG-compressed.

If you decide to load in the newly revised code (and I assume you will),
please let me know your results.

NB: I have not made the changes part of the official Unidata McIDAS-X 
distribution
yet since I am still testing the routines that will be impacted by the mods), 

Last comment:

My intention is to now seriously look at including support for 
wavelet-compressed
METEOSAT imagery.  I also intend to try and estimate the effort that it will
take to add support for the vegetation images that Tyn inquired about earlier,
but that is another Support Inquiry.  How long it will take to add support for
wavelet-compressed METEOSAT imagery is unknown...

Cheers,

Tom
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Ticket Details
===================
Ticket ID: HWT-941133
Department: Support McIDAS
Priority: Normal
Status: Closed


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