Indirect Georeferencing in Terrestrial Laser Scanning: One-Step and Two-Step Approaches

The georeferencing procedure is to transform geospatial data from a local coordinate system to a global coordinate system, notably geodetic coordinate system on a geocentric datum. In this paper, both the one-step and two-step approaches of indirect georeferencing of 3D point cloud from terrestrial laser scanning are investigated. The georeferencing procedure is applied to a real dataset acquired by a Faro Focus(3M) X130 laser scanner and the control points and targets are measured by total station TS06 plus. Five scenarios are used for the comparison between the one-step and two-step approaches in terms of both accuracies of the 3D model and time consumption. Besides, the influence of the target's configuration on the 3D model is evaluated by changing either the number or the position of the targets. The results suggest that the 3D model's accuracies when using both the one-step and two-step approaches of indirect georeferencing are comparable. Additionally, the target's configuration greatly affects the 3D model with the one-step approach of indirect georeferencing. From the rigorous analyses of the benefit and drawbacks of both approaches evaluated on the real dataset, the paper significantly contributes to the indirect georeferencing procedure when transforming the 3D point cloud acquired from terrestrial laser scanning into the geodetic coordinate system.