Hypsometers

Hypsometer is an instrument for determining heights, widely used in surveying, architecture, and forestry. Derived from Greek roots meaning height and measure, a hypsometer combines sighting and measurement to estimate the vertical dimension of distant objects or tall structures.

Most hypsometers determine height by triangulation. The observer measures a horizontal distance to the object with a tape, rangefinder, or baseline, then uses the instrument to sight the top and read the angle of elevation on a graduated scale. The height is calculated from the distance and the tangent of the angle, with a correction for the observer’s eye height above ground.

Historically, hypsometers were used by land surveyors and geographers to estimate tree heights, towers, and mountains before modern laser rangefinders and electronic total stations. Early devices relied on simple sighting tubes, protractors, and calibrated rods; later designs integrated telescopes, level references, and more precise scales to improve accuracy.

Today, the term may describe handheld optical devices or instrument attachments used in forestry to estimate tree height or in field surveying for quick height readings. In practice, hypsometry as a broader discipline often uses more advanced equipment, but the hypsometer remains a historical and pedagogical reference for height measurement.

Related instruments include the clinometer, theodolite, and altimeter.