RANSAC (random sample consensus) is the algorithm that is usually used to remove the outlier correspondences. In the paper of Fischler and Bolles, RANSAC is used to solve the location determination problem (LDP), where the objective is to determine the points in space that project onto an image into a set of landmarks with known locations. The feature trajectories over time are then used to reconstruct their 3D positions and the camera's motion. An alternative is given by so-called direct approaches, where geometric information (3D structure and camera motion) is directly estimated from the images, without intermediate abstraction to features or corners. There are several approaches to structure from motion. In incremental SfM, camera poses are solved for and added one by one to the collection. In global SfM, the poses of all cameras are solved for at the same time. A somewhat intermediate approach is out-of-core SfM, where several partial reconstructions are computed that are then integrated into a global solution. Applications Geosciences Structure-from-motion photogrammetry with multi-view stereo provides hyperscale landform models using images acquired from a range of digital cameras and optionally a network of ground control points. The technique is not limited in temporal frequency and can provide point cloud data comparable in density and accuracy to those generated by terrestrial and airborne laser scanning at a fraction of the cost. Structure from motion is also useful in remote or rugged environments where terrestrial laser scanning is limited by equipment portability and airborne laser scanning is limited by terrain roughness causing loss of data and image foreshortening. The technique has been applied in many settings such as rivers, badlands, sandy coastlines, fault zones, landslides, and coral reef settings. SfM has been also successfully applied for the assessment of large wood accumulation volume and porosity in fluvial systems, as well as for the characterization of rock masses through the determination of some properties as the orientation, persistence, etc. of discontinuities. A full range of digital cameras can be utilized, including digital SLR's, compact digital cameras and even smart phones. Generally though, higher accuracy data will be achieved with more expensive cameras, which include lenses of higher optical quality. The technique therefore offers exciting opportunities to characterize surface topography in unprecedented detail and, with multi-temporal data, to detect elevation, position and volumetric changes that are symptomatic of earth surface processes. Structure from motion can be placed in the context