Remote Sensing’s Scale Gap

Community Remote Sensing Fills the Gap

Dr. William Gail is a director within the Startup Business Group at Microsoft and director of industry relations for IEEE Geoscience and Remote Sensing Society. He also serves on the Advisory Board of Imaging Notes magazine.

How will the private sector contribute to the field of remote sensing two decades hence? Among its important new functions will be filling what may be called remote sensing’s “scale gap” — the emerging demand for human-scale observations not readily supplied by traditional spaceborne and airborne remote sensing.

To understand why this is so, it helps to first review the evolving private-sector role over the last two decades. By the late 1980s, communications and remote sensing had emerged as the two largest economic benefits from space exploration. In contrast to the robust commercial communications satellite industry, remote sensing was largely a government-led activity. The private sector supported government-led programs by building spacecraft, developing applications, and performing services under contract. A few focused markets, such as aerial imagery, were the exceptions.

About 20 years ago, this paradigm began to change. The first breakthrough came with the introduction of truly commercial remote sensing satellites by Worldview (now DigitalGlobe), Orbimage and Space Imaging (both now part of GeoEye). This was followed by consumer adoption of online mapping through portals such as Mapquest, Google, Yahoo, and Bing. The appetite for high-resolution imagery was further driven by location-centric Web sites, focused initially on high-value applications like real estate. Widespread adoption of personal navigation devices and location-based mobile applications has recently amplified the trend. Even the intelligence community has ridden these waves through commercial imagery purchase programs such as EnhancedView.

Related trends have helped nudge the center of gravity away from government toward the private sector. Technologies such as digital aerial cameras and LIDAR (light detection and ranging) systems opened new opportunities for commercial offerings. Increased government outsourcing spurred the market. Even traditional government-led systems such as the National Polar-orbiting Operational Environmental Satellite System (NPOESS) evolved toward a stronger private-sector role, though the recent NPOESS breakup into the Joint Polar Satellite System reversed this trend.

Adding to this has been the “democratization” of remote sensing. Local government sources of remotely-sensed information have grown, two examples being security cameras and traffic sensors (including private-sector offerings such as Analytical/ geographic information system tools are increasingly available to the casual user, non-government sources have emerged, and Internet content-sharing mechanisms such as WikiMapia, YouTube, and Flickr have proliferated. The extent of consumer-focused remote sensing applications may now exceed all government uses.

As we look to the next 20 years, the uses of remotely sensed information will only increase; the ability of governments and businesses to improve efficiency and grow productivity requires increasingly sophisticated information about the world in which they work. Most interesting will be demand for filling the ‘scale gap’. No longer is moderate spatial resolution with regional coverage at low refresh rates sufficient.

The scale gap reflects a current mismatch between supply and demand. Society’s demand for information at diverse space and time scales grows exponentially, while the ability of our traditional sources to supply the information grows linearly. Tomorrow’s applications will require work at a wide range of scales — global coverage with low refresh, high-resolution hyper-local, and more — with many problems spanning multiple scales. Renewable energy is a great example; accurate knowledge of both long-term climate and near-term weather are required to optimize power generation, particularly in the wind and solar sectors.

Centralized satellite and aircraft observing systems have struggled to address this gap. Such systems are ultimately limited by their cost and complexity; for the foreseeable future, budget realities will constrain the deployment of new observing systems. Governments’ focus has shifted instead to ensuring current capabilities become more efficient through international collaborations such as the Global Earth Observation System of Systems and public-private partnerships. To some extent, the private sector has stepped up with centralized remote sensing capabilities of its own, such as databases of street-level imagery from Google Street View and Bing Streetside.

These trends will continue, but centralized systems alone cannot fill the gap. An emerging field called community remote sensing (CRS) may be our best means to bridge environmental knowledge from global to local scales. CRS employs citizens and non-professionals to remotely sense and understand the world around them, and to augment our centralized systems with this knowledge.

Work similar to CRS has been done in the related areas of citizen science, citizen mapping, and e-science. But CRS itself encompasses novel techniques and skills that differ from these related disciplines. It is not just citizens taking pictures; the community can participate through calibration, validation, analysis, and many other activities that bring together the best of centralized and decentralized capabilities.

Community remote sensing is sufficiently transformational that the Institute of Electrical and Electronics Engineers (IEEE) International Geoscience and Remote Sensing Society has selected CRS as a conference theme for its upcoming international conference in Honolulu this July ( Other organizations, including the U.S. Geological Survey and the Geological Society of America, have held or are planning similar events with a community remote sensing theme.

The private sector will lead this revolution; CRS is founded on consumer technologies such as human scale sensors, personal computing, social networks, and software applications. But government policies, such as encouraging centralized observing systems with CRS adjuncts, can accelerate the transformation.

The private sector has long been a source of innovation, both in technology and business methods. Over the next 20 years, such innovation applied to remote sensing’s scale gap will be critical, allowing tight budgets to do more for less, making existing systems work more efficiently, and introducing new ways to solve society’s toughest problems.

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