# Magnification Definitions for Land Surveyors

**magnification **[OPTICS]**—**The ratio of the size of an image to the size of the object.

**magnification, angular **[OPTICS]**—**The ratio of the angle subtended at the eye by the image formed by an optical *device, *to the angle subtended at the eye by the object itself without the optical device. This is convenient to use in cases where a distance in the object cannot be measured to express a linear magnification, as in the use of a telescope.

**magnification, linear **[OPTICS]**—**The ratio of a linear quantity in the image to a corresponding linear quantity in the object. Linear magnification may be lateral or longitudinal. Lateral magnification—The ratio of a length in the image. perpendicular to the lens axis, to a corresponding length in the object. Longitudinal magnification—The ratio of a length in the image along the axis to a corresponding length in the object.

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Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

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