[Datastream #SFA-317700]: Fwd: Unidata NLDN Question

Hi Kristin,

re:
> Thanks for getting back to me so quickly!

No worries, we aim to please :-)

re:
> I think I'm slowly making some
> progress on pulling out the data from the binary file.  A large source of
> my problem stemmed from the web site I had been given, which described the
> NLDN binary data format (http://www.unidata.ucar.edu/data/lightning.html).

Interesting.  This is, in fact, the old page, and it did, in fact, leave
out important information that I added to the new page.  The problem is
that we did not delete/rename the old file on our server so that deep
links to it would break (as they should).

re:
> When I came across the link you had provided below, I was a tad confused
> about what was going on with the data file.

Rightfully so!

re:
> As far as the format of the data goes, would you be able to confirm the
> following:  I found when reading the data in that there were 19 values that
> appeared a bit like nonsense between the nhead and first tsec described in
> the NLDN binary data record table.  The third entry in that table states
> that these header bytes can be ignored.  Would you be able to confirm that
> there would be values for those header bytes and that are nonsense values
> that can be ignored?

The format of the product allows for a variable number of bytes in the
product header.  The first 4 bytes is 'NLDN'.  The next 4 bytes is
the number of 28 byte header records in the product.  All of the header
record bytes can be ignored _assuming_ that the first 4 are 'NLDN'.
They are not exactly 'nonsense', but they have no information of the
data themselves.

The important part of the record starts at 'tsec' which is the number
of seconds since the beginning of 1970.

re:
> Thanks again!

No worries.  Please let us know how you get along in your format
cracking efforts.


Cheers,

Tom
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Ticket Details
===================
Ticket ID: SFA-317700
Department: Support Datastream
Priority: Normal
Status: Closed