### Introduction

Atmospheric correction of Sentinel 2 imagery in Google Earth Engine using [Py6S](http://py6s.readthedocs.io/en/latest/).

### Installation

#### Recommended: Docker

The following [docker](https://www.docker.com/community-edition) container has all dependencies to run the code in this repository

`docker pull samsammurphy/ee-python3-jupyter-atmcorr:v1.2`

You can also build a docker container from scratch using this [Dockerfile](https://github.com/gee-community/ee-jupyter-contrib/tree/master/docker/atmcorr-ee) from the [gee-community](https://github.com/gee-community) repo.

#### Alternative: Manual installation 

This repo has the following prerequisites

- [Python 3.x](https://www.python.org/downloads/)
- [Google Earth Engine Python API](https://developers.google.com/earth-engine/python_install_manual)
- [Jupyter](http://jupyter.readthedocs.io/en/latest/install.html)
- [Py6S](http://py6s.readthedocs.io/en/latest/installation.html)

### Usage

To run the docker container with access to a web browser

`$ docker run -i -t -p 8888:8888 samsammurphy/ee-python3-jupyter-atmcorr:v1.2`

Once inside the container, authenticate Earth Engine

`earthengine authenticate`

then grab the source code for this repo

`git clone https://github.com/samsammurphy/gee-atmcorr-S2`

and run the example jupyter notebook

```
cd gee-atmcorr-S2/jupyer_notebooks/
jupyter-notebook sentinel2_atmospheric_correction.ipynb --ip='*' --port=8888 --allow-root
```

this will print out a URL that you can copy/paste into your web browser to run the code.

If the URL is *http://(something_in_parentheses)* then you will need to change the parentheses and its contents for *localhost*. A valid URL should look something like..

http://localhost:8888/?token=...

### Saving authentication

After authenticating with `earthengine` and cloning the repository you can save the changes
you've made to the container with `docker commit`. Docker commit will create a new image from
a running containers current state.

With the container still running, open a new terminal to get the container's ID:

`docker ps`

copy the ID to clipboard and run

`docker commit [ID] gee-atmcorr-s2:myauth`

to commit the image. Now if you run

`docker images`

your newly committed image should be at the top of the list.

You can now start the note book with

```
docker run -i -t -p 8888:8888 gee-atmcorr-s2:myauth 

jupyter-notebook /gee-atmcorr-S2/jupyer_notebooks/sentinel2_atmospheric_correction.ipynb --ip='*' --port=8888 --allow-root
```