What is the primary function of a stereoplotter in photogrammetry?

The primary function of a stereoplotter in photogrammetry is to create three-dimensional models from overlapping photos. This device utilizes the principles of stereoscopy, which relies on the perception of depth by presenting two slightly different images taken from different angles. When these images are viewed together, they allow the operator to perceive the height and shape of objects in the images, effectively reconstructing a three-dimensional representation of the terrain or structures captured in the photographs. This capability is essential for tasks such as mapping, terrain analysis, and creating topographic maps.

The other options, while related to photogrammetry or imagery, do not describe the main function of a stereoplotter. Measuring pixel density pertains more to image quality assessment rather than three-dimensional modeling. Stabilizing an aerial image refers to processes that ensure clarity and accuracy during image capture, but again do not involve the stereoscopic modeling function. Classifying land cover involves analyzing images to categorize different types of land use or vegetation and is more aligned with image processing techniques rather than the physical construction of 3D models.