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20020603: Gempak dcnldn decoder/encoder question

>From: Mike Leuthold <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200206032006.g53K6bJ28535

>Chiz,
>       Arizona has a Global Atmos. lightning PC from which we get
>lightning data.  In the past,  we had used McIDAS to visualize the data,
>via nldn2md.  We have been slowly moving away from McIDAS towards Gempak
>and I want to import our data into Gempak.  Normally, dcnldn is used on
>the Unidata NLDN data stream, which appears to be compressed binary.  The
>data we get from our PC is ASCII which I don't think dcnldn will decode.
>
>06/03/02 19:45:19 32.012  -81.616  +110.0  7
>06/03/02 19:45:22 32.280  -81.404   -60.0  2
>06/03/02 19:45:22 42.231  -92.739  -270.0  4
>
>
>What (and how) is the best method to get this data into .gem format?  Am I
>going to need to write a custom decoder? 
>
>
>Thanks, as usual.
>
>Mike
>
>
>--
>Mike Leuthold
>Atmospheric Sciences/Institute of Atmospheric Physics
>University of Arizona
>address@hidden
>520-621-2863
>
>

Mike,

Yes, the NLDN is binary. It also appears to have other parameters than you show.
It appears you have time, lat, lon, sgnl, and mult. The NLDN data also
has chi square, eccentricity etc.

Most of the dcnldn decoder will work for you, eg the opening of files
etc. We would need to modify the input of data, and the call that
decodes the binary to just place your data in the array that gets
written out.

The alternative would be to use SFEDIT, but its generally better to have a 
decoder so that you can pipe your data for realtim use.

Steve Chiswell