BOX 2.1
Geomatics

Geodesy provides the scientific underpinning for geomatics, a relatively new term used to describe the science, engineering, and art involved in collecting and managing geographically referenced information. A number of government agencies, private companies, and academic institutions have embraced this term as a replacement for “surveying and mapping,” which no longer adequately describes the full spectrum of position-related tasks carried out by professionals in the field. Geomatics covers activities ranging from the acquisition and analysis of site-specific spatial data in engineering and development surveys to cadastral and hydrographic surveying to the application of GIS and remote sensing technologies in environmental and land use management.

science, or engineering (primarily instrumentationrelated) departments. Again, only a few such degree programs (e.g., Massachusetts Institute of Technology, Ohio State University) currently exist in the United States. Notable examples of U.S. universities currently offering an undergraduate degree in geomatics or a graduate degree in geodesy are listed in Table A.1 in Appendix A.

Some 2-year colleges and associate degree programs in universities offer programs in surveying or geomatics technology, which provide basic instruction in the principles of geodesy, including coordinate systems and the use of GPS. There are many such colleges across the United States, whose primary purpose is to produce surveying and mapping technicians. Examples include the Geomatics Technology Program at Greenville Technical College (South Carolina) and the Engineering Technology Program at Alfred State College (New York).

Course-only master’s degrees offered by some of the institutions mentioned in Appendix A allow entry into some geodesy-related jobs. Some professionallevel education in geodesy is also available through continuing education programs and short courses offered by diverse organizations, such as the National Geodetic Survey, NavtechGPS, the Institute of Navigation, Pennsylvania State University, and the Michigan Technical University.

Undergraduate degrees or specialization in geophysics are available at a number of universities in departments of physics, earth and planetary sciences, and geology and geophysics (e.g., Stanford University, Harvard University; see Table A.1 in Appendix A). Many universities also offer master’s and doctorate degree programs in geophysics, including the California Institute of Technology and the Massachusetts Institute of Technology.

PHOTOGRAMMETRY

The term photogrammetry is derived from three Greek words: photos or light; gramma, meaning something drawn or written; and metron or to measure. Together the words mean to measure graphically by means of light. Photogrammetry is concerned with observing and measuring physical objects and phenomena from a medium such as film (Mikhail et al., 2001). Whereas photographs were the primary medium used in the early decades of the discipline, many more sensing systems are now available, including radar, sonar, and lidar, which operate in different parts of the electromagnetic radiation spectrum than the visual band (Kraus, 2004). Moreover, while most early activities involved photography from manned aircraft, platforms have since expanded to unmanned vehicles, satellites, and handheld and industrial sensors. Construction of a mathematical model describing the relationship between the image and the object or environment sensed, called the sensor model, is fundamental to all activities of photogrammetry (McGlone et al., 2004). Given these changes in the field, photogrammetry is now defined as the art, science, and technology of extracting reliable and accurate information about objects, phenomena, and environments from acquired imagery and other sensed data, both passively and actively, within a wide range of the electromagnetic energy spectrum. Although its emphasis is on metric rather than thematic content, imagery interpretation, identification of targets, and image manipulation and analysis are required to support most photogrammetric operations.

In photogrammetry, the Earth’s terrain is imaged using overlapping images (photographs) taken from aircraft or hand-held cameras, linear scans of an area from a satellite (Figure 2.3), or data from active sensors, such as radar, sonar, and laser scanners. A single image, which is a two-dimensional recording of the three-dimensional (3D) world, is not sufficient to



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