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MODIST geo files?
Posted: Wed Sep 02, 2020 2:34 pm America/New_York
by alaroy
Are geo files for MODIST available for download from oceandata? If so where should I be looking?
Or does one need to make their own from the two hourly attitude and ephemeris files?
Thank you!
-Andrew L.
MODIST geo files?
Posted: Wed Sep 02, 2020 3:23 pm America/New_York
by OB ODPS - jgwilding
Hi Andrew.
Yes, you need to create the GEO files for MODIS using the ATT/EPH data. If you're using SeaDAS to process the data, i believe the scripts do that for you.
john
MODIST geo files?
Posted: Wed Sep 02, 2020 4:37 pm America/New_York
by alaroy
John,
Thank you for the quick reply!
Just out of curiosity, why does MODISA get 5 minute attitude and ephemeris files while MODIST gets 2 hour ones?
-Andrew L.
MODIST geo files?
Posted: Wed Sep 02, 2020 5:07 pm America/New_York
by OB ODPS - jgwilding
I believe it comes down to they are on different spacecraft platforms. The Aqua data stream includes the near-real-time (NRT) ATT/EPH data that can be used to process data. Then later the refined ATT/EPH data are delivered, and any future refined L2 processing we do uses the refined ATT/EPH. Terra also has ATT/EPH data embedded in the data stream, and up to several years ago, those could be used to process the data NRT. The geo-___location software no longer supports using that data. I don't know the details of why. It might be that the accuracy of the onboard data had become bad enough to use without some post processing.
john