Generating DSM minus DTM using Agisoft Metashape Professional and QGIS
In my previous article — UAV Image Preprocessing with Agisoft Metashape, I have explained how to stitch the aerial images captured using a drone with forward and side overlaps and generate orthomosaic image using Agisoft Metashape Professional. In this article, I’ll focus on generating DSM (Digital Surface Model) and DTM (Digital Terrain Model) using Agisoft Metashape Pro, visualize them in QGIS and obtain DSM minus DTM image for calculating height of the objects present in the image.
DSM minus DTM operation is often referred to as the “height above ground” or “height of objects” and has various practical applications such as building extraction and analysis, vegetation studies, obstacle detection for infrastructure planning, floodplain mapping, 3D city modeling, change detection, and precision agriculture. It enables professionals in fields like urban planning, environmental monitoring, and GIS to assess and analyze the elevation characteristics of diverse landscapes, supporting decision-making processes and enhancing understanding of the built and natural environment. DSM represents the Earth’s surface with all features, DTM represents the bare Earth’s surface without above-ground objects, and DSM minus DTM gives a model of the above-ground features, excluding the terrain. They are used in geographic information systems…
