geesarfetcher 0.3.0

Extract Sentinel-1 GRD time-series images over a given area from google earth engine

GEE SAR Fetcher

An easy-to-use Python library to download SAR GRD imagery from Google Earth Engine.

Introduction

Access Google's multi-petabytes of SAR Imagery data from your python code with no dimension restraint. Simply supply coordinates, a time interval and obtain a stack of Sentinel-1 preprocessed PolSAR images. This enables quick data analysis of GRD images to get better insights of the temporal dimension in SAR data without having to bother with essential but potentially time-consuming steps such as coregistration or calibration.

Compatible with python 3.

Usage

Python Import

The main function of this library is the fetch function:

from geesarfetcher import fetch
from datetime import date, timedelta

fetch(
    top_left = [-104.77431630331856, 41.81515375846025], 
    bottom_right = [-104.65140675742012, 41.729889598264826],
    start_date = date.today()-timedelta(days=15),
    end_date = date.today(),
    ascending=False,
    scale=10,
    n_jobs=1
) # returns a dictionnary with access to the data through the 'stack' keyword and to its timestamps through the 'timestamps' keyword

To fetch over a single point, the process is similar to the difference that we use another function, called fetch_point and only provide a single coordinates tuple rather than either two or 5 tuples for the area query.

from geesarfetcher import fetcher
from datetime import date, timedelta

fetch_point(
    coords = [-104.88572453696113, 41.884778748257574],
    start_date = date.today()-timedelta(days=15),
    end_date = date.today(),
    ascending=False,
    scale=10
)

Installation

Access to Google Earth Engine is conditioned by the obtention of a GEE account. Once created, you can install the geesarfetcher API and register an identifying token for your Python working environment using the following commands:

pip install geesarfetcher
earthengine authenticate

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change. Please make sure to update tests as appropriate.

License

MIT