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[McIDAS #YGF-361048]: GOES R calibration



Hi Ioan,

re:
> are you aware by any chance of some documentation on McIDAS AREA
> calibration block for GOES-R

The only "documentation" that I know of is the code in the McIDAS-X
calibration module, kbxabin.dlm and the code that puts together the
calibration array in their GOES-R data servers, abinaget.cp and
abinadir.cp.  Since you previously indicated that you are licensed
for McIDAS-X, you should be able to download the latest McIDAS-X release,
v2017.2, from SSEC.

I assume that the lack of more documentation is a reflection of how
fast the code for GOES-R data serving has been evolving.

re:
> I figured out it consists for 18 elements for a given channel.

Yes, that is what I gleaned from the code.

re:
> For example,
> channel 2 from class contains following information (NetCDF) related to
> calibration
> 
> 'vis064_esun': 1618.35, 'vis064_add_offset': -20.2899,
> 'vis064_scale_factor': 0.158592, 'vis064_earth_sun_distance_anomaly_in_au':
> 0.998059
> 
> 
> the calib block from the same image (lead server) (McIDAS AREA)  looks like
> this
> 
> 
> (2, 6399999, 1585923, -202899112, 0, 0, 0, 0, 0, 0, 0, 18753, 0, -9990000,
> -9990000, -2147483648, -2147483648, 4095)
> 
> 
> I can recognize the channel/band  number (pos 0) vis064_scale_factor*100000
> (pos 2) vis064_add_offset * 1000000 (pos 3) and Nodata values (pos 17)
> o you have any clue what position 1 , 11, 13, 14, could mean

This should be more clear in the code I referred to above.

re:
> I interpreted the bytes as float as well but  could't see anything:))

It is _highly_ doubtful that any value in a McIDAS ADDE transaction would
be in floating point format.

re:
> Another aspect that concerns me a little is the DOC keyword.  As per ADDE
> doc the DOC keyword ifs set to YES, results in the line documentation
> being included in the area file.

Yes.

re:
> I use the line doc for example to compute the scan duration in seconds of
> any given image, (start scan of  last line - scan time of last line)

I asked SSEC specifically about the calculation of the time of each
scan line, and I was told that there has been some internal development
aimed at calculating the time.  I have not, however, received any specifics
about what they have developed, or if it is, in fact, accurate.

re:
> I have the feeling that line doc is not returned form the ADDE even if the
> DOC=YES

I have not investigated the effect of including DOC=YES on IMGCOPYs for GOES-16
images, so I can not comment about doc values being nor not being returned
in an ADDE transaction.  I assume that a careful review of the AGET server
code, abinaget.cp, will reveal what is really going on.  Other than that, I
know of no other documentation.

I'm sorry that I can't be a better source of the intimate details of GOES-R
ADDE transactions.  I have been forced to read poorly documented code to figure
out how to add support for the MCSTRETCH environment concept that was introduced
in SSEC's v2017.2 release... sigh!

Cheers,

Tom
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Ticket Details
===================
Ticket ID: YGF-361048
Department: Support McIDAS
Priority: Normal
Status: Closed
===================
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