EDITORIAL: Earth Observation Goes Mainstream

Though most people have never heard the term, remote sensing is entering the mainstream. NASA's Applied Sciences Program uses Earth observation to benefit society in areas as diverse as public health, agricultural efficiency, and disaster management. Satellite imagery and remote sensing analysis from the United States Geological Survey and from private companies such as Space Imaging, Orbimage, DigitalGlobe, GlobeXplorer, Spot Image, ImageSat International, and EarthSat is used by governments and corporations in hundreds of applications. Terraserver, Google Earth, and Microsoft Virtual Earth are now making this imagery familiar and accessible to millions of people.

At his company's user conference, in July, Jack Dangermond, founder and president of ESRI, the largest geographic information systems (GIS) company, predicted that the supply of satellite and aerial imagery will increase by two orders of magnitude in the next few years. Availability will also increase greatly, via Web portals and online GIS services. This is all part of what Dangermond describes as a "geodata-rich society" that will be characterized by more geospatial information of all kinds — including, in addition to imagery, GPS/location data, geo-demographic data, and data from real-time monitoring.

Growing popular awareness of satellite imagery is driving demand — in two ways. First, increased traffic on the sites that provide free imagery or sell it cheaply to the public obliges those sites to fill gaps in their coverage and update their archives with more recent images. Second, as more people view and download satellite images for personal use, they become more aware of how these images can also help them in their work. Demand, in turn, drives the continuing expansion of capacity in data collection and processing.

There are a few additional dynamics at play in the industry. One is rising expectations. It works roughly like this: In order to meet the operational requirements of specialized fields, such as precision farming or disaster management, satellite manufacturers and operators develop different kinds of satellites. This increases the number of options and data sources available to end-users who, in turn, demand even more advanced products and services. This requires still more data sources and image processing software...

Another dynamic is dropping costs, due to several factors. The demand and supply cycle just described is one. Another is progress in software. Surveying photo-identifiable ground control points has been and continues to be one of the most expensive components of any aerial photogrammetry campaign. New software and techniques that use satellite imagery to orient and georeference aerial photos greatly reduce the need for ground truthing. To the extent that ground control points are still needed, it is less and less necessary to acquire them through expensive new surveying. Instead, they can often be purchased off-the-shelf from companies that have built up huge archives. New software is also making image processing a lot less labor-intensive, which also saves money. Finally, new digital cameras are entering the market that can yield essentially the same end products as the most sophisticated ones, but at a much lower cost.

Taken together, increasing expectations, demand and supply, and dropping costs are combining to quickly make satellite images and aerial photographs ubiquitous and expected.