Surveying and Mapping Technicians

Since ancient times, people have needed to define their property boundaries. Marking established areas of individual or group ownership was a basis for the development of early civilizations. Landholding became important in ancient Egypt, and with the development of hieroglyphics, people were able to keep a record of their holdings. Eventually, nations found it necessary not only to mark property boundaries but also to record principal routes of commerce and transportation. For example, records of the Babylonians tell of their canals and irrigation ditches. The Romans surveyed and mapped their empire's principal roads. In the early days of colonial exploration, surveyors and their technical helpers were among the first and most-needed workers. They established new land ownership by surveying and filing claims. Since then, precise and accurate geographical measurements have been needed to determine the location of a highway, the site of a building, the right-of-way for drainage ditches, telephone, and power lines, and for the charting of unexplored land, bodies of water, and underground mines.

Early surveying processes required at least two people. A technical scientist served as the leader, or professional surveyor. This scientist was assisted by helpers to make measurements with chains, tapes, and wheel rotations, where each rotation accounted for a known length of distance. The helpers held rods marked for location purposes and placed other markers to define important points.

As measuring instruments have become more complex, the speed, scope, and accuracy of surveying have improved. Developments in surveying and mapping technology have made great changes in the planning and construction of highway systems and structures of all kinds. For roadway route selection and design, technicians increasingly use photogrammetry, which uses plotting machines to describe routes from aerial photographs of rural or urban areas. Route data obtained by photogrammetry may then be processed through computers to calculate land acquisition, grading, and construction costs. Photogrammetry is faster and far more accurate than former methods. In addition, new electronic distance-measuring devices have brought surveying to a higher level of precision. Technicians can measure distance more quickly, accurately, and economically than was possible with tapes, rods, and chains.

In addition to photogrammetry, the use of computers in data processing has extended surveying and mapping careers past the earth's surface. Technicians now help to make detailed maps of ocean floors and the Moon. Every rocket fired from the Kennedy Space Center is tracked electronically to determine if it is on course through the use of maps made by surveyors. The technological complexity of such undertakings allows surveyors to delegate more tasks than ever to technicians.