Photogrammetry is the science of calculating measurements from photos. Photogrammetry software is used in tools like 3DR Site Scan, which uses a drone to automatically take hundreds of photos of a specified area, then uses the photogrammetry software to identify similar points across multiple images.
Using these similar points, the system constructs a three-dimensional point cloud, which is used to generate the same topographic maps, digital terrain models, meshes, and orthophotos that engineers rely on for design and build work.
Photogrammetric point cloud
Photogrammetry is different from LiDAR because photogrammetry generates point clouds from computer vision and ray tracing, while LiDAR generates point clouds from a range finding laser. In many cases, point clouds derived from cameras and from LiDAR are nearly indistinguishable. However, photogrammetry struggles with reflective objects and dense vegetation.
The biggest difference, however, is the cost and ease of deployment. A drone platform capable of generating a photogrammetric point cloud costs significantly less than a LiDAR equipped sensor. Furthermore, the software capable of analyzing and acting on the point clouds is cheaper and easier to use.
Earthworks is the process of engineering involving excavation (cut) and movement (fill) of soils and rock for the purpose of grading a site. Drone software platforms enhance traditional earthwork processes by making it easier to collect, analyze, and share topography and volumetric data.
Revit is an Autodesk computer-aided design (CAD) software tool used for building information modeling (BIM) by design-build construction teams.
Navisworks is an Autodesk software tool used to manage, combine, and review various 3D model files.