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[netCDFJava #LOE-612985]: Nexrad decoding errors
- Subject: [netCDFJava #LOE-612985]: Nexrad decoding errors
- Date: Mon, 18 Aug 2014 16:10:40 -0600
David,
This information (courtesy of Michael James, our Gempak Guru) might be useful:
"
I think the nex2gini table calibration range is the information he is looking
for.
https://github.com/Unidata/gempak/blob/master/gempak/tables/unidata/nex2gini.tbl
For example,
N1P 30 4
inches,0,9,-9999,-9999;10,100,0,0.5;101,200,0.5,5;201,255,5,12 TICZ99
CHIZ
30 = unique product ID
4 = number of calibration ranges
inches = unit
; = delimiter for the 4 calibration ranges, containing min/mac for pixel value
followed by min/max for the unit.
I think him finding the max value of 153 is the greatest pixel value available
in that particular image. Most products use 256 levels, but N0R max possible
value is 105.
"
Ryan
> Ryan,
> Thanks for the Thredds link. I have successfully downloaded and decoded some
> of the GINI files; subsequently obtaining the PNG file and header
> information. However, I seem to be missing one bit of (important)
> information. I can't seem to find the index values within these PNGs. For
> example, in one of the DVL files, the index seems to range roughly from
> 0-253. In the N0R (reflectivity), I see index values in the PNG image go
> from 0-80. In the one hour precip (N1P), which I assume is in either mm or
> inches, the max is 153.
>
> When performing an octal dump, I can see information pertaining to 'dBz' or
> 'inches' (for n0r and n1p, respectively) around the 68th bit character, but I
> can't make sense of where the magnitude values are found. Do you have a
> publication or a method that will help me extract the corresponding index
> values to their associated dBz, inches, etc? I have referenced the
> following doc, but it describes nothing past octet 61....
> http://www.nws.noaa.gov/noaaport/document/ICD%20CH5-2005-1.pdf
>
Ticket Details
===================
Ticket ID: LOE-612985
Department: Support netCDF Java
Priority: Normal
Status: Closed