How to reproject MODIS L2 data via Python?

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
guorz
Posts: 18
Joined: Wed Apr 19, 2017 1:22 pm America/New_York
Answers: 0

How to reproject MODIS L2 data via Python?

by guorz » Sun Oct 23, 2022 11:14 pm America/New_York

Hi all,

I tried to reproject MODIS L2 data(AQUA_MODIS.20200227T052500.L2.OC.nc) to geotiff using Python, tired GCP but the result was a little misplaced. Also found that part of the lat and lon of the data is not monotonically increasing(see the picture attached), why is this and how should I deal with it while reprojecting?


Thanks,
Rachel
Attachments
微信图片_20221024111324.png
微信图片_20221024111324.png (85.61 KiB) Not viewed yet

Tags:

OB SeaDAS - dshea
Subject Matter Expert
Subject Matter Expert
Posts: 258
Joined: Thu Mar 05, 2009 10:25 am America/New_York
Answers: 0
Been thanked: 2 times

Re: How to reproject MODIS L2 data via Python?

by OB SeaDAS - dshea » Mon Oct 24, 2022 10:25 am America/New_York

You have found the MODIS Bowtie effect. Since the MODIS sensor has 10 detectors that take data on each scan, the position of the edge pixels at the beginning and end of the scan overlap the previous and next scan. Here is a web page describing this in more detail:

https://oceancolor.gsfc.nasa.gov/docs/bowtie/modis/

If you want to map MODIS L2 data, I would suggest downloading Seadas and the Science software and using the program "mapgen" to bin and map the data to almost any projection you would like.

don

guorz
Posts: 18
Joined: Wed Apr 19, 2017 1:22 pm America/New_York
Answers: 0

Re: How to reproject MODIS L2 data via Python?

by guorz » Thu Oct 27, 2022 5:23 am America/New_York

got it thanks

Post Reply