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geeguide

02.Atmospheric Correction

Objective

Atmospheric correction of Landsat7,8 and Sentinel 2 in Google Earth Engine

  • Both Landsat and Sentinel 2 images were atmospheric corrected using one Py6S model
  • TOA --> BOA using Py6S via GEE python API
  • Generate BOA dataset to your GEE asset

General Instruction

  • GEE support both Web-based Code Editor and Python API. Each environment has its own advantage and disadvantage, we will use only Python API when applying atmospheric correction, all the others tasks will be Code Editor based
  • First, please follow this instruction by Samsammurphy on atmospheric correction of a single Sentinel 2 image using Py6S. You will be guided through how to setup GEE python environment, authentication, docker, etc
  • Second, I have modified Samsammurphy's version so that we can apply it to Landsat 7, Landsat 8 and iterate to a whole image collection. You should pay attention to the part about turning on/off the Exporting to GEE Asset. Making some tests before turning on full scale is recommended.
  • If you still want to do atmospheric correction in GEE Code Editor, you can use SIAC_GEE by MarcYin.

Core Script

  • Sentinel 2 Atmospheric Correction
https://github.com/ndminhhus/geeguide/blob/master/jupyter_notebooks/02.Atm-corr-Sentinel2.ipynb
  • Landsat 8 Atmospheric Correction
https://github.com/ndminhhus/geeguide/blob/master/jupyter_notebooks/02.Atm-corr-Landsat8.ipynb
  • Landsat 7 Atmospheric Correction
https://github.com/ndminhhus/geeguide/blob/master/jupyter_notebooks/02.Atm-corr-Landsat7.ipynb

Visualization and Checking

  • Landsat 8 before-after

Landsat 8

  • Sentinel 2 before-after

Sentinel 2

References

  1. Mission specific for atmospheric correction https://github.com/samsammurphy/ee-atmcorr-timeseries/blob/master/atmcorr/mission_specifics.py
  2. Atmospheric correction of Sentinel 2 imagery in Google Earth Engine using Py6S. https://github.com/samsammurphy/gee-atmcorr-S2
  3. Introduction to the Google Earth Engine Python API https://www.earthdatascience.org/tutorials/intro-google-earth-engine-python-api/
  4. Py6S: A Python interface to the 6S Radiative Transfer Model http://rtwilson.com/academic/Wilson_2012_Py6S_Paper.pdf
  5. 6S radiative transfer model https://doi.org/10.1109/36.581987
  6. Basic writing and formatting syntax https://help.github.com/en/articles/basic-writing-and-formatting-syntax#relative-links