How to apply the Band math to multiple images

Hello everyone!
I am a beginner in Python programming and I need to collocate four daily ocean color images and calculate the band math for eight bands, and I need to do it for 10 years of daily images! I was wondering if there was a code on automatic collocation and also the band math calculations.
Thank you a bunch!

Hi, sorry but this is not a Python froum. We mainly answer questions about SNAP. There are some things you can do with SNAP if your images have the right format and they can be read. You have not specied which sensor you use or what is the final target of your time series analysis.

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Thank you Ana for your reply. Actually, I’m using MODIS-MERIS merged images to extract chlorophyll concentration from band ratios. However, I have daily images for ten years. That’s why I was trying ti find a way to facilitate the work.

@Ocean_9 look at Graph Builder.

It’s possible to do this in Python, but setting up the environment is a royal pain. Once you have the Graph built in GraphBuilder, you can run it in batch mode.

Collocate is under Geometric


I would also say, that if you are new to python, snappy is probably not for you.
But you might want to use SNAPISTA (
And as @cndnflyr suggested. You can set up the processing chain in the graph builder modify it and use it from the command line.
How to use gpt from the command line is explained here:
Bulk Processing with GPT - SNAP - Confluence (

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@cndnflyr & @marpet I sincerely appreciate your help. I’m going to go through your advices rightaway.