Analytical Picture Control Points Survey for Terrain Photogrammetry

Terrestrial photogrammetry without ground control points

Terrestrial photogrammetry should be the survey technique of choice when updating large scale urban maps and GIS databases, where 3D data and attribute data are required. Its main drawback is the need for Ground Control Points (GCP) to reference the survey. To make image georeferencing easier and to provide control information, the use of a simple system, made of a photogrammetric camera fasten...

A Morphological Reconstruction Algorithm for Separating Off-terrain Points from Terrain Points in Laser Scanning Data

During the last decade various techniques have been proposed to extract the ground surface from airborne LIDAR data. The basic problem is the separation of terrain points from off-terrain points which are both recorded by the LIDAR sensor. In particular geometry driven filtering, detection or classification procedures are developed which use knowledge to find points, e.g. on buildings or vegeta...

Geodesic Spanners for Points on a Polyhedral Terrain

Let S be a set S of n points on a polyhedral terrain T in R, and let ε > 0 be a fixed constant. We prove that S admits a (2 + ε)-spanner with O(n log n) edges with respect to the geodesic distance. This is the first spanner with constant spanning ratio and a near-linear number of edges for points on a terrain. On our way to this result, we prove that any set of n weighted points in R admits an ...

Assessing the Value of UAV Photogrammetry for Characterizing Terrain in Complex Peatlands

Microtopographic variability in peatlands has a strong influence on greenhouse gas fluxes, but we lack the ability to characterize terrain in these environments efficiently over large areas. To address this, we assessed the capacity of photogrammetric data acquired from an unmanned aerial vehicle (UAV or drone) to reproduce ground elevations measured in the field. In particular, we set out to e...

Distribution of Rational Points: A Survey