altimetrie

Altimetrie, also known as altimetry, is the scientific discipline that deals with the measurement and determination of the elevation of points on the Earth's surface relative to a reference datum, most commonly mean sea level. The term originates from the Latin word altus, meaning high, and the Greek metron, meaning measure. Its primary objective is to create accurate topographic maps, to monitor changes in terrain, and to support applications in geodesy, civil engineering, environmental science, and navigation.

The development of altimetrie began in the 18th century with barometric pressure methods, which used the inverse relationship between atmospheric pressure and altitude. The 19th century saw the introduction of the trigonometric leveling technique, employing triangulation networks and precise angle measurements to calculate elevation differences more accurately. By the mid‑20th century, electronic distance measurement (EDM) devices and photogrammetric techniques further improved precision and efficiency.

Modern altimetrie largely relies on satellite technologies. Global Positioning System (GPS) receivers provide three‑dimensional position data, while radar and laser altimeters aboard aircraft and satellites deliver remote sensing elevation information with centimeter to meter accuracy over large areas. The Shuttle Radar Topography Mission and the TanDEM‑X mission are prominent examples of satellite‑based altimetric mapping projects.

Applications of altimetrie span various domains. In civil engineering, it informs the design of infrastructure such as roads, bridges, and pipelines. In environmental studies, it helps monitor glacial retreat, sea‑level rise, and erosion patterns. Navigation systems, both terrestrial and maritime, depend on accurate elevation data for route planning and collision avoidance. Furthermore, altimetrie is essential in modeling atmospheric processes, as atmospheric pressure and temperature vary with altitude.

Challenges remain in achieving globally consistent vertical datums, especially in regions far from sea‑level references. Advances in satellite technology, real‑time kinematic GPS, and statistical data fusion are continually enhancing the precision and reliability of altimetric measurements.