hypsometri

Hypsometry is the measurement and analysis of the distribution of elevations on the Earth's surface. It examines how land and seabed occupy different heights relative to a chosen reference level, typically mean sea level. The term is used in geomorphology, cartography, and planetary science to describe the vertical dimension of landscapes and to summarize elevation distributions through curves and indices.

Data and methods: Elevation data come from topographic maps, digital elevation models (DEMs), LiDAR, satellite altimetry, and bathymetric surveys. Elevations are binned and a hypsometric curve is constructed by plotting the cumulative area or fraction of area below each elevation against elevation (often normalized to the observed minimum and maximum). The curve provides a compact representation of how elevations are distributed within a region and can reveal the overall shape of the relief.

Hypsometric integral: The hypsometric integral (HI) condenses the curve into a single dimensionless value, commonly defined as HI = (mean elevation − min elevation) / (max elevation − min elevation). HI measures the relative relief and the apparent stage of landscape evolution. Higher HI values typically indicate greater relief and younger, more tectonically active terrains, while lower HI values suggest flatter or older surfaces. Interpretations depend on the study area, scale, and data extent.

Applications and scope: Hypsometry supports analyses in geomorphology, hydrology, and sedimentology, informing understanding of erosion, uplift, and climatic effects on landscapes. It is also applied in planetary science to compare global topography across planets and moons, aiding in interpretations of tectonics and surface processes beyond Earth.