Archaeology Term: Alidade
An archaeology/alidade'>alidade is a surveying instrument used to measure angles and distances, historically employed to create detailed topographic maps and top plans.
Aligning its sights along a straight edge, the alidade enables precise measurements of horizontal and vertical angles. By combining these measurements with distance data, surveyors can accurately determine the position of points in space. This information is essential for creating detailed maps and plans, which are crucial for various applications, including civil engineering, urban planning, and archaeology.
Historically, alidades were used in conjunction with other surveying instruments, such as theodolite and level. The surveyor would set up the alidade on a tripod and align the sights with a distant point. By reading the scales on the alidade, they could record the angle between the line of sight and a reference direction.
While alidades have played a significant role in the history of surveying, they have largely been replaced by more advanced technologies, such as total stations. Total stations are electronic surveying instruments that combine the functions of a theodolite, distance meter, and data recorder.
These devices offer greater accuracy, speed, and automation, making them the preferred choice for modern surveyors.
Despite their historical significance, alidades continue to be used in educational settings to teach the principles of surveying and the evolution of surveying technology. By understanding the limitations and capabilities of traditional instruments, students can appreciate the advancements in modern surveying techniques.
