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[McIDAS #AMH-341410]: 2 questions



Hi Ioan,

re:
> i have a question for you.
> 
> How do you plan to encode/supply the scan mode and end of scan time for the
> L1B GOES16 in the  Area files/stream served through ADDE?

From what I can see (SSEC wrote the ADDE server for the ABI imagery in the GRB),
the ABI scanning mode is not saved anywhere in the AREA file header (ADDE makes
all images look like they are in AREA file format).

I was going to guess that the scan end time is being encoded as the time that
the image was created, but this does not appear to be the case.

Here is the example that I am basing my comments on:

/data/ldm/pub/native/satellite/GOES/GRB16/ABI/FullDisk/Channel13/current: 
ncdump -h 
OR_ABI-L1b-RadF-M3C13_G16_s20173031500407_e20173031511185_c20173031511246.nc
netcdf 
OR_ABI-L1b-RadF-M3C13_G16_s20173031500407_e20173031511185_c20173031511246 {
dimensions:
        y = 5424 ;
        x = 5424 ;
        number_of_time_bounds = 2 ;
        band = 1 ;
        number_of_image_bounds = 2 ;
        num_star_looks = 24 ;
variables:
 ...
// global attributes:
 ...
                :timeline_id = "ABI Mode 3" ;
                :date_created = "2017-10-30T15:11:24.6Z" ;
                :time_coverage_start = "2017-10-30T15:00:40.7Z" ;
                :time_coverage_end = "2017-10-30T15:11:18.5Z" ;
                :created_by = "CSPP Geo GRB-R v0.4.6" ;

Now, the IMGLIST listing for the same image (I IMGCOPYed the image to
my local MYDATA/IMAGES dataset so I can examine the AREA headers returned
in detail):

Image file directory listing for:MYDATA/IMAGES
 Pos Satellite/         Date       Time      Center      Res (km)   Image_Size
     sensor                                 Lat  Lon    Lat   Lon
 --- -------------  ------------  --------  ---- ----  ----- ----- ------------
3000  G-16 IMG      30 OCT 17303  15:00:40     0   89
   Band: 13   10.3 um IR Surface & cloud                2.02  2.00  5424 x 5424
     proj:    0 created: 2017303 151909  memo: GOES-R Full Disk
     type:ABIN     cal type:RAW
     offsets:  data=    3076 navigation=  256 calibration=  768 auxiliary= 3076
     doc length:   0   cal length:   0   lev length:   0 PREFIX=   0
     valcod:          0 zcor:  0 avg-smp: A
     lcor:    1  ecor:     1  bytes per pixel: 2  ss:186
     Resolution Factors (base=1):   Line=    4.0   Element=    4.0
IMGLIST: done

From these two listings, I see that the image's nominal time is being
set from the 'time_coverage_start' value.  I expected that the value in
the 'created:' entry in the IMGLIST listing would have been either the
'date_created' value or even the 'time_coverage_end' value, but it
is neither.  I'll have to examine the server code in detail to see how
the 'created:' value is being set.

Since this is surprising to me, I'll send in an inquiry to the MUG for
clarification.

Question:

- why is the ABI scanning mode important to you?

  I can imagine some reasons, but I want to know what your perspective
  is.

re:
> (i assume you are going to publish L1b data)

Yes, we will be serving the L1b images as those are the ones that
are being produced by CSPP GEO.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: AMH-341410
Department: Support McIDAS
Priority: Normal
Status: Closed
===================
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