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The Democratization of Remotely Sensed Data
Democratization - The action of making something accessible to everyone.
- Oxford Languages
The field of remote sensing has undergone a major shift over the past few decades. Pushes towards open data frameworks have resulted in astronomical growth in the acquisition and use of remotely sensed data. In the past, access to and use of these data were both expensive and exclusive. I provide examples below about how the Landsat program and technological advancements in drone platforms have helped in democratizing remote sensing for the masses. I emphasize that researchers, small organizations, start-up companies, land managers, and more, are now able to access remotely sensed data on demand and make important multidisciplinary impacts.
The Landsat Revolution
Launched in 1972, the Landsat Program is considered a pioneering effort for Earth observation. With a continuous archive from 1972-present, it is the world’s longest continuously acquired collection of space-based moderate-resolution remote sensing data. This archive continues to provide us with insight into how our world has changed over time, and allows us to establish trends for what it may look like in the future. Landsat data are used around the world for scientific research, educational training, and product development amongst many others, but it hasn’t always been this way.
Initially, Landsat data needed to be purchased by users or agencies. Costs ranged from $20 for a scene (individual image) up to $4000 for much of 1983–1998. While there was still use and adoption of Landsat data, these costs were largely cost prohibitive for research and development. This all changed in October 2008 when the United States Geological Survey (USGS) implemented a policy to provide Landsat data to users at no cost over the internet. This free and open data policy contributed to a surge in multidisciplinary use of Landsat data.
We can see in the figure from Wulder et al. (2022) that an exponential increase in published research using the Landsat archive occurred immediately after the implementation of the USGS free and open policy. This democratization of Landsat data resulted in significant contributions to many different science and application areas including land cover mapping, agriculture, forest management, ecology, biodiversity, and many more.
One may wonder, why release Landsat data for free? Other than scientific research, what are the benefits? The Landsat Advisory Group sought to answer this question by determining the relative cost of other technologies to accomplish tasks that Landsat is relied upon such as risk management, monitoring global security, forest health monitoring, and support for fire management. Results indicated that sixteen common Landsat applications provided relative savings of up to 436 million dollars each year for the US government, NGO’s, and private sector. These savings are substantial, and make a strong case for continuing advocacy for democratization of remotely sensed data.
Expansion of Drones
Let's fast forward to the last decade and come down from space to about 100 meters above the ground. Drones have revolutionized environmental research and management. Unlike traditional remote sensing data and methods that require extensive resources, drones can be launched quickly, cost-effectively, and on-demand, to provide a birds eye view of areas of interest. They have been a driving force in the democratization of remotely sensed data in that they have lowered barriers to entry for high-resolution data acquisition that can be tailored to the user's needs. In many cases, drones and the sensors they carry provide the first examples of individuals being able to acquire bespoke, analytical quality remote sensing data.
Drone hardware and software have both seen rapid development. Carbon-fibre frames make them lightweight yet robust, GPS and flight-planning software simplify navigation and risk avoidance, and a wide range of imaging sensors from basic three-color cameras to advanced laser altimeters (LiDAR) and thermal sensors exist. The variety of drone sizes, battery endurance, data capture capabilities, and capacity for finely tuned movement provide flexibility for users to tailor their data to achieve their objectives. Its important to note that regulations around drone use vary widely globally and users should always abide by pertinent regulations.
As mentioned above, satellite or aircraft-based data has historically been prohibitively expensive. People used to need to wait for imagery to be available for their area of interest, and much of the time it was either too expensive or didn't provide a fine enough spatial resolution for their use case. Drones now provide a means to acquire sub-centimeter spatial resolution imagery on demand. They have become essential tools for monitoring areas of forests, rivers, agriculture, and wildlife, as well as reducing risk for dangerous tasks such as power line inspections and natural disaster assessments.
Closing Thoughts
Concerted efforts to democratize remotely sensed data through the open access release of the Landsat satellite archive, or development of drone platforms and sensors has created a new paradigm for geoscience and environmental monitoring. These tools and datasets continue to demonstrate the power of remote sensing, providing a means for anyone and everyone to be involved in earth observation, no matter the application. I encourage anyone interested to take a look at open access remote sensing initiatives like Open Topography. Just like Landsat’s open access release, the more data people can access, the more unique perspectives, approaches, and methodologies can be applied to improve how we monitor and manage our ecosystems.
References
- Fifty years of Landsat science and impacts, ScienceDirect.
- Disturbance-Informed Annual Land Cover Classification Maps of Canada's Forested Ecosystems for a 29-Year Landsat Time Series, Canadian Journal of Remote Sensing.
- Forest Monitoring Using Landsat Time Series Data: A Review, Canadian Journal of Remote Sensing.
- From imagery to ecology: leveraging time series of all available Landsat observations to map and monitor ecosystem state and dynamics, Zoological Society of London.
- Use of Landsat and SRTM Data to Detect Broad-Scale Biodiversity Patterns in Northwestern Amazonia, MDPI.
- Benefits of the free and open Landsat data policy, Science Direct.
- Desktop Flight Planning, DroneDeploy.
- Unmanned aerial systems for precision forest inventory purposes: A review and case study, Canadian Institute of Forestry.
- Automated detection of wildlife using drones: Synthesis, opportunities and constraints, British Ecological Society.
