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[ldmMcidas #XGX-360555]: decoding FNEXRAD 1 km N0R composite images

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  • Subject: [ldmMcidas #XGX-360555]: decoding FNEXRAD 1 km N0R composite images
  • Date: Thu, 02 Aug 2007 07:09:30 -0600
Hi Elmer,

re:
> So, there is no BREF that decodes to McIDAS area file?  That needs to be
> our output, since it is used as input data by several other applications.

The 1 km N0R (aka BREF) image you are currently grabbing is in GINI format
(after being uncompressed by pngg2gini).  The 2 km N1P (PRE1, 1-hour precip)
and 4 km NTP (PRET, precip total) products are also in PNG-compressed
GINI format.

The FNEXRAD feed also has a 6 km N0R composite (BREF) in PNG-compressed AREA
format:

Example FNEXRAD header:

pnga2area Q5 RL 300 RADAR BREF 6km 20070802 1219

It also has the several radar composites -- including the national
1 km N0R composite -- in GRIB format:

Example FNEXRAD headers:

radar_mosaic_national !grib/unidata/UPC_1/#255/200708021223/F000/N0R/sfc! 000000
radar_mosaic_national !grib/unidata/UPC_1/#255/200708021223/F000/NET/sfc! 000001
radar_mosaic_nathr !grib2/unidata/UPC_255/#000/200708021223F000/N0R/0 - NONE! 
000000

If you are licensed to use McIDAS from SSEC, you have a couple of options:

1) a) create an ADDE dataset of the 1 km N0R composites
   b) create an ADDE dataset whose contents are AREA files as input/output
   c) do an IMGCOPY from the GINI dataset to the AREA dataset; McIDAS will
      transparently do the conversion from GINI to AREA for you

2) grab a bundle of XCD decoders we make available.  This bundle contains a
   McIDAS routine called GRIBDEC which converts a field in GRIB1 format to
   McIDAS AREA.  This is the routine that we use to create the 6 km AREA product
   in the FNEXRAD feed; it can just as easily create an AREA from the
   1 km N0R GRIB message in the FNEXRAD feed to a McIDAS AREA

Cheers,

Tom
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Ticket Details
===================
Ticket ID: XGX-360555
Department: Support ldm-mcidas
Priority: Normal
Status: Closed