The operational environment and the variety of activities and products have also changed dramatically. The range of products has broadened beyond image products (e.g., single, rectified, and orthorectified images; mosaics; radar products) to point and line products (e.g., targets, digital surface models, digital elevation models, point clouds, vectors) to relative information products (e.g., lengths, differences, areas, surfaces, volumes) to textured 3D models. Photogrammetry products now provide the base information for many geographic information systems (GIS). Finally, many processes are being automated, allowing near-real-time applications. The next phase may well be called on-demand photogrammetry, with many activities based online. It is likely that processing will be pushed upstream toward the acquisition platform, making it possible to obtain information products, rather than data, from an airborne or satellite sensor. Direct 3D imaging may be imminent. Photogrammetry will likely continue to play a significant role in ascertaining precision and accuracy of geospatial information, and to contribute to the complex problem of fusing imagery with other data.
Knowledge and Skills
Photogrammetry classes are taught in undergraduate programs in surveying, surveying engineering, geomatics, or geomatics engineering, but none of these programs in the United States offer a bachelor’s degree in photogrammetry. The graduates of such programs may be employed in mapping firms, particularly if they took an extra elective course in photogrammetry. They would know how aerial photography and other imagery is acquired and how to use it in stereoscopic processing systems to extract various types of mapping information. It is likely that they would receive significant on-the-job training by seniors in their firm.
The individuals who obtain a master’s degree in photogrammetry gain much more knowledge based on a strong mathematical foundation. Such photogrammetrists or photogrammetric engineers design algorithms to exploit various types of imagery. They understand the different platforms and have a command of the techniques of least-squares adjustment and estimation from redundant measurements. Photogrammetric scientists usually have a doctorate and are capable of supervising or carrying out research and modeling the various complex imaging systems. They conceive of novel approaches and ways to deal with technological advances, whether in new sensors, new modes of image acquisition from orbital platforms or aircraft, or in the integration and fusion of information from multiple sources.
Education and Professional Preparation Programs
Education programs in photogrammetry (e.g., Ohio State University, Cornell, Purdue University) flourished in the early and mid-1960s. At the time, photogrammetry was being used extensively by the Defense Mapping Agency, the U.S. Geological Survey, the U.S. Coast and Geodetic Survey, the military services, and the intelligence community. Demand for training was high, and these organizations sent significant numbers of employees to universities under programs such as the Long Term Full Time Training (LTFTT) program. By the late 1980s and early 1990s, more than 25 photogrammetry programs were offering both master’s and doctorate degrees in the field. At the undergraduate level, photogrammetry was introduced as a small part of undergraduate courses in surveying and mapping. In the 1980s and 1990s, several institutions (e.g., Ferris State, California State University, Fresno) offered lower-level photogrammetry courses as part of their undergraduate bachelor’s programs in forestry, geography, civil engineering, construction engineering, surveying engineering, and, most recently, geomatics. About that time, the Defense Mapping Agency embarked on a modernization program (MARK 85 and MARK 90) to convert to digital imagery and move toward automation. The agency’s focus on professional development shifted from learning fundamental principles to mastering skills to run software for photogrammetry applications. By the mid-1990s, the number of students taking classes through the LTFTT program and its successor Vector Study Program began to decrease significantly, and the decline in enrollment reduced support for educational programs offering a substantial emphasis in photogrammetry.
3 Although terms such as radargrammetry and lidargrammetry are sometimes used to emphasize the type of sensor data being analyzed, the fundamentals of photogrammetry apply to all types of sensor data.