What is a Digital Surface Model (DSM)?

What is a Digital Surface Model (DSM)?

A DSM (Digital Surface Model) is a three-dimensional elevation model of an area, created by including the surface of the earth plus all objects on it (buildings, trees, bridges, power lines, etc.). It is one of the most frequently produced model types in drone photogrammetry and LiDAR measurements.

The search term "digital surface model" often aims to understand the difference between SAM and SYM: DSM represents the all-encompassing top surface, while SAM represents the bare land.

Where is DSM Used?

Construction and site monitoring: Building volume, stock area, and progress measurement
Infrastructure and energy projects: Obstacle and height analysis along line routes
Forest and land management: Surface model including tree cover
Urban planning: Building heights and silhouette analysis
Mining: Quarry and stockyard volume calculations
Drone mapping: 3D terrain model production with orthomosaics

How is a DSM Created?

DSM; Drone photogrammetry is generated from LiDAR or laser scanning data. Coordinate accuracy is ensured with ground control points (GCP). Output formats can be GeoTIFF, LAS/LAZ, or grid models suitable for the project software.

Important Notes

DSM should not be considered a "terrain model" on its own. For excavation-fill and slope analyses, SAM (Surface-Mounted Map) is generally required; SAM is derived from DSM by filtering out buildings/trees. The project specifications must clearly state which model is required.

KG Engineering

We produce DSM, SAM, and orthomosaics using drone photogrammetry and LiDAR. You can find details about our services on our Drone Mapping and Engineering Measurements pages.