Drone photogrammetry
Photogrammetry is the art and science of turning 2D photographs into realistic digital models. By capturing an object, building, or landscape from multiple angles, we can reconstruct its shape and texture. It bridges the gap between the physical and digital worlds, allowing us to preserve history, create immersive virtual environments, and map our planet with incredible precision.
The 2D Orthomosaic ​
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Data Collection - The process begins by capturing a series of overlapping images. This overlap is crucial, ensuring that points on the ground are visible from multiple angles.
Photogrammetry Processing - Specialized software analyzes these overlapping images to identify thousands of common "tie points." It triangulates their position in 3D space to reconstruct the scene's geometry.
The Orthomosaic - The primary output is an Orthomosaic: a highly detailed map created by stitching the images together. Unlike a standard photograph which has perspective distortion (where things look smaller further away), an orthomosaic is geometrically corrected. It allows you to measure true distances and areas directly on the image with map-like accuracy.
Elevation Models - From the 3D data, we can derive distinct layers for analysis:
DSM (Digital Surface Model): Captures the "top" of the world, including trees, shrubs, and structures.
DEM (Digital Elevation Model): Filters out vegetation to reveal the "bare earth" terrain underneath.
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Orthomosaic example
DEM
DSM
The 3D Point Cloud​
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While the orthomosaic process creates 2D maps, the point cloud creates a 3D model. By processing millions of overlaps in the drone imagery, we generate a dense cloud of data points, where every single dot represents a precise X, Y, Z coordinate in 3D space.
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This data is essential for volumetric and vertical analysis. It allows us to measure roof pitch, calculate the biomass of vegetation, or model line-of-sight, metrics that a flat map simply cannot provide.
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Explore the Data: Interact with the viewer below to navigate a point cloud of a house and backyard. Zoom in to see the millions of individual points that construct this digital model. Double click on a point in the cloud to center on that area.
I created this point cloud using a DJI mini 3 pro to capture photos, OpenDroneMap to create the orthomosaic above and 3D point cloud, CloudCompare to crop and subsample the point cloud, and Potree to create the interactive viewer.