Google Earth Engine (GEE) Workshop
What is GEE? What can we use it to do?
What is GEE?
Google Earth Engine is a remote-sensing big data platform for geospatial processing service. It can solve some global challenges that involve large geospatial datasets.
It is free for research, education, and non-profit.
(1) Cloud-based platform for geospatial analysis
(2) Access over 40 years of satellite imagery (over 50 Petabytes data)
(3) Easy to upload own datasets and export results generated via GEE
How many datasets in GEE?
By Simon Ilyushchenko and Sulien O’Neill, on behalf of the Earth Engine Data team
GEE contains nearly 1000 datasets and it is still growing ( Earth Engine Data Catalog) .
Landset, MODIS, Sentinel, DEM, Land cover, and so on.
How can GEE do?
These are some examples showing in the GEE.
Landsat Images (Australia)
Global Land Cover Map
Global Snow Cover Map
Global Night Temperature Map
Global Terrain Visualization
Nighttime Light in Florida
You can achieve your research goal via your own codes.
How to access to GEE?
Firstly, you need to sign up a GEE account for accessing.
Here is the link: https://signup.earthengine.google.com
Sign Up Pages
Here, I recommend you use the education or similar email for signing up with academic purpose.
Once you have signed up and get the permission of GEE, you can write your own code in Google Earth Engine Code Editor.
Here is the link: https://code.earthengine.google.com/
Google Earth Engine Code Editor (from https://blog.csdn.net/yuanqilian/article/details/115531600 )
In Code Editor, the acceptable language is JavaScript, and it is modified to be suitable for GEE. Besides, Google opens the API for Python use so you can code in Jupyter Notebook with Python API.
Here are some useful websites for assisting your GEE exploration!
Google Earth Engine Guides
The guides are written primarily for JavaScript in the Code Editor with examples for Python in Colab where applicable. The JavaScript Quickstart guide and the tutorials describe basic concepts and example workflows to help beginning users.
Here is the link: https://developers.google.com/earth-engine/guides
Geemap
Geemap is a Python package for interactive mapping with Google Earth Engine (GEE), which is a cloud computing platform with a multi-petabyte catalog of satellite imagery and geospatial datasets. It is developed by Dr. Qiusheng Wu in University of Tennessee.
Geemap is intended for students and researchers, who would like to utilize the Python ecosystem of diverse libraries and tools to explore Google Earth Engine. It is also designed for existing GEE users who would like to transition from the GEE JavaScript API to Python API. The automated JavaScript-to-Python conversion module of the geemap package can greatly reduce the time needed to convert existing GEE JavaScripts to Python scripts and Jupyter notebooks.
Here is the link: https://geemap.org/
Cloud-Based Remote Sensing with Google Earth Engine
In order to use Earth Engine well, you will need to develop basic skills in remote sensing and programming. The language of this book is JavaScript, and you will begin by learning how to manipulate variables using it. With that base, you’ll learn about viewing individual satellite images, viewing collections of images in Earth Engine, and how common remote sensing terms are referenced and used in Earth Engine.
Here is the link: https://www.eefabook.org/
What did I do via GEE?
Automated Glacier Snow Line Altitude Calculation Method Using Landsat Series Images in the Google Earth Engine Platform
Most of the world’s glaciers are currently experiencing mass loss, which will contribute to a host of global environmental problems, such as increasing glacier meltwater, rising sea level, and increasing water scarcity.
Mountain glaciers form a critical component of the cryosphere and are sensitive to climate change.
Careser Glacier changes during the 1986–2021
The glacier equilibrium line altitude (ELA), which is representative of the annual glacier mass balance and the response of that glacier to climate change, is defined as the glacier position where its annual ablation equals accumulation.However, this field-based approach is unfeasible for monitoring many mountain glaciers due to their remote environments and limited observation sites.
The SLA is defined as the glacier position that marks the maximum surface extent of snow cover, with bare ice present below the SLA and snow cover present above the SLA. Therefore, observations of the glacier SLA can be used to assume the ELA.
Framework
Framework
Graphical Abstract
Result
Glaciers Mean Snowline in High Mountain Asia
More details and codes can be found here: Li, X.; Wang, N.; Wu, Y. Automated Glacier Snow Line Altitude Calculation Method Using Landsat Series Images in the Google Earth Engine Platform. Remote Sens. 2022, 14, 2377. https://doi.org/10.3390/rs14102377
Let's start to code in GEE
01 Basic Syntex
02 Import Shapefiles in FeatureCollection
03 Select Images and Remove Cloud in ImageCollection
04 Calculate the Index (NDVI, NDWI)
05 Export Result
Thank you very much!
Email: xiang11@usf.edu