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[GEMPAK #QYA-206571]: Embarassing Simple GINI format question, how to convert 8bit raster to actual data
- Subject: [GEMPAK #QYA-206571]: Embarassing Simple GINI format question, how to convert 8bit raster to actual data
- Date: Fri, 21 Nov 2014 12:06:42 -0700
Hi Daryl,
For the Unidata FNEXRAD GINI images there is a calibration block in the unused
portion of the GINI header that is used for the image calibration values.
In gempak/source/gemlib/im/imgi2gm.f:
C* Get calibration Block if it exists.
C* Currently, only Unidata calibrations exist, using
C* Word 47 = 128
C* to signal that a calibration block is present.
followed by CALL IM_CALBAR_INIT and then building of the calibration values
from the header on line 311.
These calibration ranges are defined in $GEMTBL/unidata/nex2gini.tbl
For non-Unidata GINI images, I'm looking in the ICD at
http://www.nws.noaa.gov/noaaport/document/ICD%20CH5-2005-1.pdf
Page 24 mentions the nav/cal block:
7. Octet 47, Navigation/Calibration Indicator
Set to 0 to indicate no nav./cal. information included
(PDB = 512 octets, octets 48-512 are blanks)
Set to 1 to indicate nav. and cal. information included
Set to 2 to indicate nav. information only included
Set to 3 to indicate cal. information only included
(For values 1-3, PDB size will likely increase
to no more than 2048 octets). Additional ICD tables
will be generated defining nav./cal. octets for each of
the creating entities (satellite/imagery types) for
which nav./cal. is to be included.
Is this what you're looking for?
-Michael
> Hi Unidata,
>
> Please hit me with the clue-by-four, but I can't seem to resolve how to
> properly convert the 8bit value stored in GINI format products to an
> actual data value. Is there some GEMPAK table that describes this or
> something in the GINI header that describes it?
>
> thanks
> daryl
>
> --
> /**
> * Daryl Herzmann
> * Assistant Scientist -- Iowa Environmental Mesonet
> * http://mesonet.agron.iastate.edu
> */
>
>
Ticket Details
===================
Ticket ID: QYA-206571
Department: Support GEMPAK
Priority: Normal
Status: Open