getanc.py

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
avmehta
Posts: 177
Joined: Mon Feb 03, 2020 10:27 am America/New_York

getanc.py

by avmehta » Mon Jun 08, 2020 4:18 pm America/New_York

Hello,
     I have a question about l2gen output file. In the L2 netcdf output file I see longitudes slon, clon, and elon. And similar for latitude. I use clon and clat of each pixel as geolocation of that pixel when using in calculations. Is this a correct assumption?
Thanks.
Amita

Tags:

OB.DAAC - SeanBailey
User Services
User Services
Posts: 1276
Joined: Wed Sep 18, 2019 6:15 pm America/New_York
Answers: 1

getanc.py

by OB.DAAC - SeanBailey » Mon Jun 08, 2020 6:11 pm America/New_York

No. There are full lat/lon arrays in the L2 files.  The s/c/e variants are a holdover from the original SeaWiFS L2 files, which didn't have full lat/lon arrays. (Rather subsampled arrays). You can ignore the s/c/e arrays.

Sean

OB.DAAC - SeanBailey
User Services
User Services
Posts: 1276
Joined: Wed Sep 18, 2019 6:15 pm America/New_York
Answers: 1

getanc.py

by OB.DAAC - SeanBailey » Tue Jun 09, 2020 10:59 am America/New_York

It would be a problem if you were....lonlat2pixline works on the unprojected L1/2 files.

There is no consistent method to identify clouds in L1 data.  For the three missions you're interested in, there is some hope, though.... 
OLCI includes a qualityFlags.nc file that has, among others, a flag for "bright" targets.
OLI are TIFF images, but does include a "BQA" image that includes a bit for clouds
MSI are JPEG2000 images, but also include in the directory a subdirectory under "GRANULE" called QI_DATA that includes a set of XML files with flag information....good luck with that...

Sean

Post Reply