What is a manual style stereoplotter that has three angular rotations called?

A manual style stereoplotter that allows for three angular rotations is termed a direct optical stereoplotter. This equipment is specifically designed to create topographic maps by interpreting overlapping aerial photographs. The three angular rotations enable the operator to adjust the viewing angle, thereby providing a three-dimensional perspective that helps in the accurate representation of elevations and contours on a map.

The term "direct" refers to the ability of the stereoplotter to derive stereo imagery directly from the photographs without requiring additional digital input or processing, setting it apart from digital or automated plotters that operate using software and computer inputs. This manual equipment is crucial for surveyors who need precise control during the mapping process in diverse terrains, making it a valuable tool in traditional surveying practices.

Other options, while they may involve aspects of stereoscopic mapping or plotting, do not encompass the same manual three-rotation capabilities integral to the functioning of the direct optical stereoplotter.