English: An alidade (archaic forms include alhidade, alhidad, alidad) is a device that allows the user to sight a distant object and use the line of sight to perform a task. This task can be, for example, to draw a line on a plane table in the direction of the object or to measure the angle to the object from some reference point. Angles measured can be horizontal, vertical or in any chosen plane.
This category has the following 2 subcategories, out of 2 total.
Media in category "Alidades"
The following 86 files are in this category, out of 86 total.