Re: Display of satellite data

Hi Mey-

Mey Manickam wrote:
I am trying to display local satellite images - a sequence of AREA files. I could load it, but nothing appears in the display. I tried running visad/examples/SatDisplay( I am using AreaAdapter to read a McIdas Area file as it is done in this example ). In the past I remember running this example with success. Now if I run without any arguments or explicitly specifying an Area file as an argument I get this exception:

[mem@xodus examples]$ java SatDisplay
visad.VisADException: Problem getting Area file directory or navigation
      at visad.data.mcidas.AreaAdapter.buildFlatField(AreaAdapter.java:126)
      at visad.data.mcidas.AreaAdapter.<init>(AreaAdapter.java:100)
      at visad.data.mcidas.AreaAdapter.<init>(AreaAdapter.java:60)
      at SatDisplay.<init>(SatDisplay.java:123)
      at SatDisplay.main(SatDisplay.java:205)

Line 126 in the current AreaAdapter is a javadoc line so I suspect
you are running an old version of SatDisplay.  If this is true, you
are probably getting the error because the location of the default
AREA file (AREA2001) changed from www.ssec.wisc.edu to ftp.ssec.wisc.edu.

I just ran the current version and it worked fine.

[mem@xodus examples]$ java -mx64m SatDisplay AREA0007
visad.VisADException: Problem getting Area file directory or navigation
      at visad.data.mcidas.AreaAdapter.buildFlatField(AreaAdapter.java:126)
      at visad.data.mcidas.AreaAdapter.<init>(AreaAdapter.java:100)
      at visad.data.mcidas.AreaAdapter.<init>(AreaAdapter.java:60)
      at SatDisplay.<init>(SatDisplay.java:123)
      at SatDisplay.main(SatDisplay.java:205)

Is AREA0007 in the same directory that you are running SatDisplay
from?  Again, since the error line listed in AreaAdapter is not
in buidlFlatField in the current code, I'm guessing that you are
using an old version.

Any hints?

Update to the latest version of VisAD and try SatDisplay with
no args again.  Also, since the file is loaded off an FTP
server, make sure that you have a network connection and that
you can do an FTP transaction (i.e. make sure it's not blocked
by a firewall).

If you can give more details on what you are running to load
in your local files, perhaps I can help more.  Make sure you
have ScalarMaps set up to show the display.  You'd need one for
XAxis, one for YAxis and one to RGB for the sat data.

Don
*************************************************************
Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
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