modis_atteph.py usage

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smasse
Posts: 20
Joined: Wed Dec 05, 2018 3:58 pm America/New_York

modis_atteph.py usage

by smasse » Fri Jul 01, 2022 9:51 pm America/New_York

Hello,
I am trying to understand how modis_atteph.py works. I have an example below. When I enter a date/time close to the current time, it gives such an error. Is there a URL or a manual that explain the algorithm or at the very least the exit codes? Especially when the increase in latency causes problem with the processing.

spike.seadas[1042]% date -u ; date -u +%j
Sat Jul 2 01:44:13 UTC 2022
183
spike.seadas[1043]% /usr/local/seadas/7.5/scripts/modis_atteph.py -f -m terra -s 2022182160500 -e 2022182161000; echo $?
att1=/home/seadas/MODIS/ancillary/2022/182/AM1ATTN0.A2022182.1600.002
eph1=/home/seadas/MODIS/ancillary/2022/182/AM1EPHN0.A2022182.1600.002

0
spike.seadas[1044]% /usr/local/seadas/7.5/scripts/modis_atteph.py -f -m terra -s 2022183000000 -e 2022183050000; echo $?
Traceback (most recent call last):
File "/usr/local/seadas/7.5/scripts/modis_atteph.py", line 125, in <module>
m.findweb()
File "/usr/local/seadas/7.5/scripts/modules/anc_utils.py", line 439, in findweb
self.files[str(f[0]).lower()] = str(f[1])
IndexError: string index out of range
1

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smasse
Posts: 20
Joined: Wed Dec 05, 2018 3:58 pm America/New_York

Re: modis_atteph.py usage

by smasse » Sat Jul 02, 2022 7:11 pm America/New_York

Sorry about the initial submission. I noticed I set the stop time 5 hours after the start time instead of 5 minutes. I assume it cause a problem if the period is too long. I have another question.
I tried modis_atteph.py as follow:
/usr/local/seadas/7.5/scripts/modis_atteph.py --mission=terra --start=2022183160135 --stop=2022183161735
It returned
att1=/home/seadas/MODIS/ancillary/2022/183/AM1ATTN0.A2022183.1400.002
eph1=/home/seadas/MODIS/ancillary/2022/183/AM1EPHN0.A2022183.1400.002
The att & eph files cover only 14:00 to 16:00 hours which is outside the stop/start given. Does this mean I would have to verify the range covered by the returned att/eph to make sure it includes the entire given period? Am I missing something?

OB SeaDAS - xuanyang02
Subject Matter Expert
Subject Matter Expert
Posts: 362
Joined: Tue Feb 09, 2021 5:42 pm America/New_York
Answers: 1

Re: modis_atteph.py usage

by OB SeaDAS - xuanyang02 » Tue Jul 05, 2022 11:44 am America/New_York

Right, the stop time can't be more than 2 hours later than the start time.

For SeaDAS 7.5, modis_atteph used to return

0 - all is well in the world
1 - predicted attitude selected
2 - predicted ephemeris selected
4 - no attitude found
8 - no ephemeris found

We recently changed the api which modis_atteph called to retrieve ancillary data, and the return status was changed to

0 all is well
1 att/eph files are not optimal
2 att/eph files missing

Unfortunately, SeaDAS 7.5 users have to live with it.

We are working to resume the return status for modis_attpeh for future tags of ocssw.

I ran modis_attepeh (ocssw_v2021.2) as the following, which should behave similar as modis_attph.py in SeaDAS 7.5

$ modis_atteph --mission=terra --start=2022183160135 --stop=2022183161735
Running debug binaries...
/Users/*/ocssw-V2021.2/bin
ancillary_data.db
att1=/Users/*/ocssw-V2021.2/var/anc/2022/183/AM1ATTN0.A2022183.1400.002
att2=/Users/*/ocssw-V2021.2/var/anc/2022/183/AM1ATTN0.A2022183.1600.002
eph1=/Users/*/ocssw-V2021.2/var/anc/2022/183/AM1EPHN0.A2022183.1400.002
eph2=/Users/*/ocssw-V2021.2/var/anc/2022/183/AM1EPHN0.A2022183.1600.002

The reason you did't get

AM1ATTN0.A2022183.1600.002
AM1EPHN0.A2022183.1600.002

is that they were not available at the moment.

Bing

smasse
Posts: 20
Joined: Wed Dec 05, 2018 3:58 pm America/New_York

Re: modis_atteph.py usage

by smasse » Wed Jul 06, 2022 8:19 am America/New_York

Thanks for the quick answer.

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