Re: [idvusers] observation file does not open in IDV

• To: idvusers@xxxxxxxxxxxxxxxx
• Subject: Re: [idvusers] observation file does not open in IDV
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Wed, 05 Mar 2014 09:33:59 -0700

Hi Hein:

http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html

John

On 3/5/2014 4:05 AM, Hein Zelle wrote:

Dear IDV users,

I have a problematic observation file which I can't open with
IDV.  It is of the type "point" feature, and has a record axis
with independent observations.  Each record has separate longitude,
latitude, time and data values.

The original file which _does_ work is here:

http://freja.argoss.nl/file-exchange/Surface_Synoptic_latest.nc

I have tried to compress the file by doing the following:

1) remove large variables
2) change record axis to a fixed axis
3) scale floats and ints to short
4) add netcdf4 format and compression

The resulting file is here:

http://freja.argoss.nl/file-exchange/test_packed_surface.nc

The result (< 1mb) is indeed much smaller than the original (23mb) and
contains identical thata for those variables I have kept.  However:

Step 1 is fine, IDV reads the file.

Step 2 makes the file unreadable for IDV, although I don't see why it should.

Step 3 doesn't achieve compression without step 2
        (netcdf pads variable records to 4 bytes)

Step 4 doesn't achieve compression without step 2
      (variable records to small for compression algorithm)


Could anyone help me in making this file work in IDV?

I've tried to track down the source code in the java-netcdf source
code that reads point data files, but so far I didn't succeed.  A
pointer to the right source file would be great, so I can try to
make it work.


Kind regards,
      Hein Zelle

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  • [idvusers] observation file does not open in IDV
    • From: Hein Zelle