MODIS navigation

Errors and unexpected results
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kbedka1
Posts: 428
Joined: Wed Jan 28, 2009 7:27 pm

MODIS navigation

Post by kbedka1 »

I am also having another issue with MODIS within hydra. I am processing some MODIS data with other A-train datasets in IDL. For this, I am using the multispectral MYD021km data with the MYD03 1 km navigation. See attached example, the maximum latitude of the data is ~5.3 deg N. When draw my green subset box to display the northernmost portion of the granule in Mc-V, the maximum latitude indicated by the cursor is 4.3 N. In the region from the attached line plot, the cursor claims the latitude is Is the cursor output wrong, or is the data not being navigated properly?

Kris
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Picture 34.png
Picture 37.png
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tdrink
Posts: 157
Joined: Wed Apr 15, 2009 7:45 pm

Re: MODIS navigation

Post by tdrink »

The multispectral datasource only uses the 5km nav in the MOD02 file, so
there's probably some truncation on the edges. The navigation is as close
to correct as we can do with the sub-sampled nav - in general coastlines
match up pretty well with the corresponding image boundaries.
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kbedka1
Posts: 428
Joined: Wed Jan 28, 2009 7:27 pm

Re: MODIS navigation

Post by kbedka1 »

I think this 5 km/1 km isuue may contribute to the problem I'm seeing, but after running this problem with another case, I think the lat/lon from the cursor output can be way off on occasions.
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jayh
Posts: 413
Joined: Thu Jan 15, 2009 10:34 pm

Re: MODIS navigation

Post by jayh »

Hi Kris-

I'll put this information into an inquiry for evaluation as well... http://mcidas.ssec.wisc.edu/inquiry-v/?inquiry=654

Thanks for the information.

-Jay
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Rick
Posts: 404
Joined: Fri Jan 16, 2009 8:20 pm

Re: MODIS navigation

Post by Rick »

Kris,

Could you please post your files for further testing/debugging.

Thanks,

Rick
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