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pietern / goestools

Tools to work with signals and files from GOES satellites
https://pietern.github.io/goestools/
BSD 2-Clause "Simplified" License
372 stars 83 forks source link

channel numbering issues #48

Closed eminence closed 5 years ago

eminence commented 5 years ago

Following up to the comments in 96dc5544290e6f2742564a8795b960103a09a513 with an issue for better visibility.

num can be zero, which is tripping up the assertion. Here's the whole nlh structure:

(gdb) print num
$1 = 0
(gdb) print nlh
$2 = {static CODE = 129, headerType = 129 '\201', headerLength = 14, agencySignature = "NOAA", productID = 16, productSubID = 0, parameter = 0,
  noaaSpecificCompression = 1 '\001'}
(gdb) print text
$3 = "Time of frame start = 2019-05-16T04:54:38.4Z;Satellite = G16;Instrument = FM1;Channel = N/A;Imaging Mode = ABI Mode 6;Region = Mesoscale;Resolution = 0.5km at nadir;Segmented = no"
pietern commented 5 years ago

Thank you. Can you confirm this is not an issue for the full disks?

pietern commented 5 years ago

I had a series of packets that didn't contain meso's and I assumed it would be the same for them.

eminence commented 5 years ago

yes, it seems the full discs are fine. in a different debugging session, i also extracted the lrit filename as OR_ABI-L2-CMIPM1-M6C02_G16_s20191360506385_e20191360506442_c20191360506509.lrit which is channel 02 of M1 i think

pietern commented 5 years ago

Added another commit that falls back on extracting the channel from the filename.

eminence commented 5 years ago

Cool, looking good. I've successfully downloaded the full set of products (goes16 fd/m1/m2, plus goes17/fd).

But I've also noticed that the channel name is again being set to an integer, and not "N/A".

The last file that I downloaded with a "N/A" channel was OR_ABI-L2-CMIPF-M6C13_G16_s20191361230342_e20191361240062_c20191361240137.lrit and the first image that had a valid channel name was OR_ABI-L2-CMIPF-M6C08_G16_s20191361230342_e20191361240050_c20191361240127.lrit. So maybe this was a temporary ground station glitch?

pietern commented 5 years ago

Great, thanks for the confirmation.

I pinged Seth at NOAA about this issue and it turns out this was caused by a GOES-16 failover to a backup system that was already running a newer version of the PDA software. He then switched back to the primary running an older version which made the Channel = N/A disappear again.

Also see the big thread on the goestools-users mailing list here.

eminence commented 5 years ago

Good info, thanks. I had seen the goestools-users mailing list, but struggled to participate. In that thread you linked there are 2 messages that are marked as "This message has been deleted" -- that was me trying to post. Do you see anything on your end about this?

Either way, this issue now seems pretty well solved, so I'll close this.

pietern commented 5 years ago

Hmm -- I didn't see those messages. I haven't heard of issues with this mailing list before.

Did your subscription go through?