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Terrestrial laser scanners (TLS) are used for a variety of applications, e.g., surveying, forestry, cultural heritage preservation, mining, topographic mapping, urban planning, forensics etc. This technology has made a huge shift in 3D spatial data collection due to much faster speed compared to other techniques. In the absence of guiding principles for positioning TLS relative to an object, surveyors collect data at maximum arrangements of scanning geometry elements due to fear of incomplete data of TLS. In 3D spatial data acquisition, positional accuracy and Level of Detail (LOD) are major considerations and are dependent on laser incident angle, footprint size, range and resolution. Mathematical models have been developed relating range, incident angle and laser footprint size for different surface configurations. These models can be used to position TLS to collect data at required positional accuracy and LOD. Models have been verified by deriving one model from other surface models by changing parameters. Effects of incident angle and footprint size have been studied mathematically and experimentally on a natural sloping surface. From the results, surveyors can plan the positioning of the scanner so that data is collected at the required accuracy and LOD. [ABSTRACT FROM AUTHOR]

LIDAR data offer an unprecedented accurate new interpretation tool for detecting terraced landscapes. The boundaries of terraced areas in Slovenia cannot be clearly defined without the help of a field survey even when the configuration of the terrain makes surveys difficult. The segmentation of point cloud data into various classes of foliage, ground, buildings, and so on makes previously hidden earthwork structures (including abandoned terraces) instantly recognizable. The conceptual shift is that the LIDAR slope analysis layer is more revealing and instructive for discovering terraces areas than orthophoto images ever were. Although LIDAR data are a new tool in the search for terraced areas, orthophotos remain important but are nevertheless only a contextual aid. A quantitative comparison between the old and new methods shows no difference in three pilot areas, shows only a minor difference in two cases, and reveals major differences in three pilot areas. The quantitative differences in some of the pilot areas are compelling. However, the most significant feature of the new method is its reliability for detecting the exact boundaries of terraced areas. [ABSTRACT FROM AUTHOR]

The route design method developed here is proposed to define the least-elevation differences between the grade and ground line. The method is based on setting the grade line as closely as possible to the natural ground level. The objective function of the proposed model is thus described with the topographic features of the area. The longitudinal gradient is taken as a condition and the minimization of the elevation differences between grade and ground line performs the objective function. The decision variables of the method are the horizontal coordinates within the boundaries of the study region. Initially, the proposed grade profile of the route is computed and determined by the three-dimensional coordinates of given start and end points. Then, the cross section stations are taken at regular intervals along the grade line. The adequate horizontal coordinates of the cross section stations are obtained by intersecting the grade lines and contour levels. The reliability of the model relies on standard deviation of elevation differences along the profile. The results show that the model may be used as a guide for route selection facilities based on topographic features of the area of interest. The methodology is implemented using a graphical interface and function developed in Matlab programming language. [ABSTRACT FROM AUTHOR]