Earth Engine is a powerful tool for analysing data about the Earth and how it is changing. As the need for geospatial data increases across all industries, more and more people are turning to Google’s Earth Engine to see what it can do. In this post, Dr Minerva Singh, remote sensing data scientist and educator, answers your questions about Earth Engine.
What is Google Earth Engine?
Google Earth Engine (GEE) is a cloud-based platform for planetary-scale geospatial analysis that combines satellite imagery, geospatial datasets, and a robust suite of data analysis tools. It allows users to process large amounts of geospatial data and perform complex analyses on a global scale, making it a valuable resource for research, environmental monitoring, and mapping applications.
GEE provides access to several petabytes of open-source geospatial data, including the complete Landsat archives (from the 1970s onwards), optical and radar data from Sentinel, digital elevation models (DEMs) and other elevation data, including the Shuttle Radar Topography Mission (SRTM) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM).
Additionally, GEE includes datasets on precipitation, temperature, and other climate variables, such as the Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), the Global Historical Climatology Network (GHCN) and access to land cover and land use datasets, such as the National Land Cover Database (NLCD), the Global Land Cover Facility (GLCF), and the International Geosphere-Biosphere Programme (IGBP).
Over the past few years, GEE has also started providing access to social-economic and demographic data, such as the Gridded Population of the World (GPW) and the Global Rural-Urban Mapping Project (GRUMP). Hence, it is unsurprising that GEE is also used in environmental monitoring and mapping applications, including land use and land cover change, natural resource management, and disaster response. GEE has been used to quickly assess the extent and impact of natural disasters such as floods, wildfires, and earthquakes and support agricultural monitoring (monitor crop growth, detect crop stress, and assess crop yields). Owing to such detailed global-scale spatial-temporal datasets, GEE has been extensively used for global scale, national and sub-national scale environmental analysis.
How does Google Earth Engine work?
The GEE platform gives users access to:
- Petabytes of publicly accessible remote sensing imagery and other ready-to-use products;
- high-speed parallel processing and machine learning algorithms using Google's computational infrastructure;
- a library of Application Programming Interfaces (APIs) with development environments that support well-known programming languages like JavaScript and Python 1. Data processing in GEE is done either using Javascript (via its web-interface or using Python (through Google Colab notebooks).
What can you do with Google Earth Engine?
GEE burst into the academic consciousness when the forest cover change maps developed by Dr Mathew Hansen as a part of their research published in the Proceedings of the National Academy of Sciences (PNAS): "High-Resolution Global Maps of 21st-Century Forest Cover Change” became available via the platform 2 as the Global Forest Change (GFC) dataset (figure 1).
Over the past decade, this GEE dataset (along with many other GEE datasets) has spawned an entire body of GEE-driven analysis and academic publications. One of the latest pieces of research used GEE to identify the shortcomings of these data in identifying forest loss in the Brazilian Amazon 3. Things have come full circle!!
Since its launch in 2010, GEE has been primarily used in academia. However, given its powerful computational capabilities and vast repository of different datasets, it is unsurprising that government and private sector organisations have started using GEE.
Many companies use GEE for environmental impact assessment (EIA). One example of a company that has used GEE for EIA is Woodside Energy, an Australian oil and gas company. Woodside Energy used GEE to conduct an EIA of a proposed liquified natural gas (LNG) development in Western Australia. The company used GEE to map and monitor wetlands, seagrass beds, and other ecosystems in the area and to assess the potential impact of the development on these ecosystems. The company also used GEE to track the movement of migratory birds, which are important indicators of ecosystem health, and to assess the potential impact of the development on these birds.
Another example is BHP, a mining multinational that used GEE for environmental impact assessment of their mining operations in Chile. The company used GEE to map and monitor land cover change, water bodies, vegetation and other environmental variables, to evaluate their operations' environmental impact and design mitigation measures. Esri, a leading provider of geographic information system (GIS) software and services, developed a flood monitoring solution that uses GEE to process large amounts of satellite imagery and other geospatial data and to create interactive maps and visualisations that can be used to track the extent and impact of floods in real-time. This solution uses remote sensing data and models to monitor water levels, track flood extent, and predict future flood risk, providing critical information to support emergency response and recovery efforts.
The National Aeronautics and Space Administration (NASA) uses GEE for flood monitoring. NASA developed the Global Flood Monitoring System (GFMS) that processes satellite data to monitor flood extent and severity globally. National and international agencies use GFMS to support flood forecasting, warning, and management 4.
Is Google Earth Engine free?
GEE is available to private businesses via a commercial licence. The Earth Engine API for Business is the Google Earth Engine (GEE) commercial licence. It's a paid licence that allows businesses, organisations, and government agencies to access the full range of GEE's capabilities and data and to use GEE's data and tools for commercial purposes. This licence is designed for organisations that process large amounts of geospatial data, perform complex analyses, and create custom applications for business-critical decision-making.
The Earth Engine API for Business licence provides businesses access to GEE's powerful data processing and analysis capabilities and support and training resources to help them get the most out of the platform. It also enables businesses to integrate GEE's data and tools with their systems and workflows, allowing them to make better decisions and improve their operations. It's important to note that the Earth Engine API for Business licence is subject to Google's terms of service and privacy policies. That usage of GEE's data and services must be compliant with these policies.
GEE continues to remain free for academic users. However, academic users must sign up for the platform (using a Gmail account) and state they are pursuing non-commercial usage.
Learn more about the advantages and disadvantages of Google Earth Engine here.
Dr Minerva Singh
Dr Minerva Singh is a data scientist and educator specialising in deep learning and Earth observation. She holds a PhD (University of Cambridge, UK), MPhil (School of Geography, and Environment) and an MSc (Department of Engineering) from Oxford University. Over 90,000 students have taken her online training courses on remote sensing in R and Python on platforms like QGIS and Google Earth Engine.