band math on bands in 2 different files

bruce · by **bruce** » Wed May 06, 2020 8:20 am America/New_York

If one has 2 different files, each with a band that has the exact same lat/lon coverage and one wants to do a difference between the 2 bands, how does one specify the band in "the other" file?

gnwiii · by **gnwiii** » Wed May 06, 2020 10:08 am America/New_York

Are you using the SeaDAS 7 GUI or writing an XML processing graph for GPT? Were both files created using the same software?

In the GUI you should see the band(s) from the other file in the list of bands. If you don't see the list, it may be because there is some (tiny) difference in the mapping.
SeaDAS Tutorial: CaseStudy (Sea Surface Temperature Anomalies) uses collocation to get bands from multiple sources into one file.

bruce · by **bruce** » Wed May 06, 2020 11:07 am America/New_York

Using the GUI, both files were created with the same software. I was able to get it done with collocating, but that seems like overkill (and a PITA).

gnwiii · by **gnwiii** » Wed May 06, 2020 3:14 pm America/New_York

If you are confident of the mapping, you can apply the "navigation" (SeaDAS 6 terminology) from one file to the other using `beampy`. The same code can be adapted to ESA SNAP's snappy.

by **OB.DAAC - SeanBailey** » Wed May 06, 2020 3:25 pm America/New_York

If the files have the exact same geolocation, then Band Maths will allow you to select bands from different input files. In the "Edit Expression" dialog, there will appear a drop-down menu by the "Data Sources" label.
The files are given a numerical variable prefix, e.g. pic / $2.pic

Sean