How do we map the bare earth without removing every tree and building manually?

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: Digital elevation models strip away the world's surface clutter to reveal the raw terrain beneath. By synthesizing radar, satellite, and airborne data, these three-dimensional grids allow scientists to model everything from flood risks to wildfire paths, providing a precise, uncluttered view of the planet's topography that traditional maps cannot match.

At its core, a digital elevation model (DEM) is a three-dimensional representation of the earth's surface. While the term is often used generically, technical distinctions exist: a digital terrain model (DTM) specifically maps the bare ground, whereas a digital surface model (DSM) includes features like building roofs and tree canopies. Creating a DTM from high-resolution DSM data requires complex algorithms to perform 'bare-earth extraction,' filtering out human-made and natural obstructions to isolate the underlying landscape.

The foundation of modern global elevation mapping was laid in February 2000 by the Shuttle Radar Topography Mission (SRTM). Using radar interferometry equipment mounted on the Space Shuttle Endeavour, this mission captured topographic data for nearly 80% of the Earth's surface. This effort provided the first near-global dataset, which has since been refined by subsequent missions like the Terra satellite’s ASTER instrument and the ICESat satellite. Today, these models are available at resolutions as fine as 30 meters per pixel globally, with newer high-resolution projects offering data at two-meter resolution for specific regions.

Data acquisition relies heavily on remote sensing, particularly radar and stereoscopic optical imagery. Techniques like interferometric synthetic aperture radar (InSAR) allow satellites to measure elevation by comparing radar signals from different angles or passes. While these models are essential for scientific analysis, they are also frequently rendered into visual formats—such as hillshade maps or color-coded elevation models—to make complex geographic data accessible. However, some researchers caution against 'vertical exaggeration' in these visualizations, arguing that scaling elevation differences can mislead viewers about the true nature of the landscape.

The evolution of these models continues through initiatives like the EarthDEM project, which coordinates efforts between NASA, commercial operators, and academic centers. By integrating emerging technologies like lidar, which maps terrain with unprecedented detail, scientists are improving our ability to monitor natural resources and hazards. Whether used for predicting water flow or planning ecological conservation, these models serve as a critical, continuously updated digital twin of the Earth's physical form.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• How computer cartography transformed the map from a static image into a living tool
• How a 200-foot mast in space mapped nearly 80% of Earth's land surface
• Machine learning creates more accurate global terrain maps by removing forest and building artifacts
• New high-resolution global map provides detailed land-cover classification at 30 meters
• How NASA tracks the Earth's changing elevation using a single orbit of light
• Why our maps put the sunrise on the right side
• The 1950s algorithm that still powers modern navigation and handheld scientific calculators
• How do you map the invisible movement of ideas, trade, and wind?
• Why a 19th-century map projection sparked a fierce, decades-long academic war
• Why your computer is a family member, not just a collection of silicon parts
• Beyond Maps: The Ancient Art of Cataloging the World's Every Detail
• Why your map is a lie: the art of cartographic generalization

More in Technical geography · More in Countries & Cities · Latest · A–Z · All topics