The precision of height measurements derived from laser scanning a weathered rock surface was analysed. Different registration methods for comparing surfaces to deduce weathering were assessed and the most precise was found to be the method
that used registration shapes as control, located in different planes relative to the scanned surface. In addition, the different sources of error in scanning precision were assessed by varying factors such as scan distance, lens configuration, scan angle
and the nature of the topography being scanned. From this analysis it was possible to suggest what the optimal scanning conditions were for this particular experimental set-up. The procedures outlined for assessing errors in the precision of height measurements
Roughness determination of coarse grained alpine river bed surfaces using Terrestrial Laser Scanning data
Bavaria ; Germany ; Grain size distribution ; Mountain ; Research technique ; River bed ; Roughness ; Stream ; Terrestrial laser scanning
The goal of this research is to improve upon the methods for roughness length determination in gravel-bed rivers using terrestrial laser scanning (TLS). To this end, 2 principle methodological considerations were examined. 1.) The influence
methods. Several test sites in the Reintal valley, Bavaria, Germany were scanned from multiple orientations. The results from these experiments show that despite minor particle shading, roughness length determination does not depend significantly
on the number of scan orientations used. However, results clearly show that roughness length determination depends highly on the choice of grid cell size during post processing. This study supports the use of TLS as the most appropriate and versatile method
of the number of scan positions on roughness calculation. 2.) The influence of grid-cell size on roughness calculation during post-processing. Scan data were furthermore compared to sediment samples to relate TLS-data to conventional roughness calculation
Application and comparison of the results of optical and scanning electron microscopic methods for grain-shape examination on Quaternary formations
Loess-paleosol and paleoclimatic investigations. Principles, methods and criteria
The purpose of this study was to determine the facies of sand sediment from Quaternary geological profiles in the Nyírség area in North Hungary, and compare the results of the traditional grain-shape examination procedures with those of the scanning
Roof type determination from a sparse laser scanning point cloud
Brno ; Bâtiment ; Mesure laser ; Modèle ; Modèle numérique de terrain ; Pardubice ; Scanner tridimensionnel ; Sobotka ; Tchèque république ; Toit ; Ville
3D scanner ; Brno ; Building ; Czech Republic ; Digital elevation model ; Model ; Roof ; Town ; laser measures
A method for determining a roof coverage type and a building height from a sparse laser scanning point cloud was introduced in Hofman (2008). A new model driven method is presented, which is suitable for buildings with a rectangular plot. Based
Quantifying interpolation errors in urban airborne laser scanning models
La méthode est susceptible d'applications multiples dans la modélisation des surfaces urbaines. Identification et analyse de l'amplitude de la structure spatiale des résidus provenant des modèles airborne laser scanning, à des échelles multiples. Il
Confocal scanning light microscopy is a valuable new method for examining the nature and progress of stone weathering at a level of resolution between optical microscopy and scanning electron microscopy. Not only is it non-destructive, but it can
Digital elevation model ; Experiment plot ; Gully erosion ; Italy ; Research technique ; Rill wash ; Soil erosion ; Terrestrial laser scanning ; Umbria ; Water erosion
This paper reports the results of a field investigation on the rill morphology and the corresponding soil loss, using a Terrestrial Laser Scanner (TLS), at the Masse experimental station (Umbria, Central Italy). For this paper 5 scans were made
of some rills, which formed during particularly erosive rain in the plots of the Masse station. The point cloud was first interpolated by the natural neighbor method to create a discrete 0.02 m × 0.02 m square cell grid Digital Elevation Model (DEM) used
for mapping the flow network. Three methods were applied to the DEM for detecting the channel network : the slope method (Horn, 1981; Wood, 1996), the constant drop method, described by Broscoe (1959) and the method of landform curvature (Tarolli et al., 2012
,) can be detected robustly using scanning XRF method, only 5 elements (Si, Ca, Fe, Sr and Zr) can be employed confidently to infer the chemical weathering and grain size sorting effects. Comparison of scanning XRF-derived elemental data with magnetic
sections) samples were collected from the Gulang loess section on the northwestern Chinese Loess Plateau for conventional and scanning X-ray fluorescence (XRF) analyses. Results suggest that although 10 elements (Al, Si, K, Ca, Ti, Fe, Zn, Rb, Sr and Zr
Evaluating the potential of an airborne laser-scanning system for measuring volume changes of glaciers
Special issue : Methods of mass balance measurements and modeling
in autumn 1997. Preliminary results from Unteraar Glacier are presented, and the potential of this method for the generation of DEMs of firn area is discussed.
Evaluating volumetric glacier change methods using airborne laser scanning data
Comparative study ; Digital elevation model ; Error ; Geodesy ; Glacier ; Glacier fluctuation ; Glacier mass balance ; LiDAR ; Methodology ; Switzerland ; Terrestrial laser scanning ; Valais
In this study the AA. used high-resolution airborne laser scanning data from the Findelengletscher in the Swiss Alps to evaluate state-of-the-art volumetric glacier change methods. For the first time they have been able to simulate errors arising
from different geodetic methods and spatial resolutions. The evaluation showed that, although the digital elevation models were perfectly co-registered, systematic and random method- and scale-dependent errors still occurred. These errors have an impact
on the resulting volume changes at lower spatial resolutions and may lead to exponentially larger uncertainties. Volume changes from contour methods provided reasonably accurate results, while volumetric change assessments from central profile lines were especially
Measuring bluff erosion part 1 : terrestrial laser scanningmethods for change detection
Algorithm ; Bank erosion ; Colorado ; Data processing ; Erosion rate ; Escarpment ; LiDAR ; Methodology ; Remote sensing ; Terrestrial laser scanning ; United States of America ; Watershed
This paper highlights challenges and limitations of using terrestrial laser scanning (TLS) for change detection on river banks and bluffs including the presence of vegetation, natural surface crenulations, and difficulties with creating benchmarks
, and provides solutions developed to overcome these limitations. Results indicate that data processing algorithms for change detection can have a significant impact on the calculated erosion rates, with different methods producing results that can vary by over
100%. The most accurate change detection technique compares a point cloud to a triangulated irregular network (TIN) along a set of vectors that accommodate bluff curvature. This paper outlines a variety of methods used to measure bluff change via TLS
and explains the accompanying error analysis that supports these methods.
A quantitative scanning electron microscope study of evidence for lichen weathering of limestone, Mendip Hills, Somerset
Les lichens saxicoles altèrent les roches carbonatées mais leur importance dans le modelé n'a pas encore été clairement déterminée. Exposé d'une méthode simple de quantification de l'altération des roches par les lichens, au microscope électronique
Boulders of 2 coastal areas (Cape Skalas in southern Lakonia, Peloponnese; Cape Gerogombos on Paliki Peninsula in western Greece were surveyed within their topographical context using a laser scanner in combination with a DGPS. 3D reconstruction
allows the determination of highly accurate volumetric data, as well as the extraction of further parameters, such as elevation above sea level, inclination and distance to the sea for each boulder. The results show that terrestrial laser scanning
the common method in scientific studies on boulder dislocation. The AA. found that volume data based on axes measurements together with density approximations result in a considerable overestimation of the mass of dislocated boulders.
Towards accurate determination of surface height using modern geoinformatic methods : possibilities and limitations
Over recent decades several modern geoinformatic methods have emerged, including global positioning system (GPS), interferometric radar, and airborne laser scanner (ALS) or lidar. In conjunction with the conventional survey and photogrammetric
method, they have found wide applications that demand varying levels of accuracy. In this paper, the principles of each method are briefly summarized. The discussion then concentrates on the accuracy level achievable with each method.
The proposed algorithm uses the matrix of distances between the observations, which are sorted in ascending order. The algorithm scans the matrix once, and only calculates the minimum of new distances to form the next class. The algorithm is exact
for the single linkage and variance methods, and is heuristic for the centroid method.
In this paper an approach to measure and quantify surface roughness in the field based on laser scanning technologies is presented. Between June 2004 and November 2005, 97 in-situ measurements were conducted in a test site with two different sandy
and temporal dynamics in surface roughness as well as substrate-specific variations. Temporal roughness variations could be detected and were linked to precipitation patterns. The methods presented in this paper are considered suitable to generate high
In situ characterization of grain-scale fluvial morphology using Terrestrial Laser Scanning
Digital elevation model ; England ; Grain size distribution ; Gravel ; Hertfordshire ; Methodology ; Micromorphology ; Scotland ; Sediment load ; Stream ; Terrestrial laser scanning ; United Kingdom
Terrestrial Laser Scanning (TLS) is a laser ranging technique, applying the same principles as airborne Lidar. It offers a new methodology for the rapid acquisition of high-resolution and high-precision surface elevation data from in situ sediments
. This paper presents the use of TLS as an alternative method for collecting high-resolution 3D data from fluvial gravel surfaces, enabling the development of grain-scale Digital Terrain Models (DTMs). Application to a coarse grained gravel system, the River
Water surface mapping from airborne laser scanning using signal intensity and elevation data
The AA. present a novel, automatic method for water surface classification and delineation by combining the geometrical and signal intensity information provided by airborne laser scanning (ALS). The reflection characteristics of water surfaces
[b2] Christian Doppler Lab. Spatial Data from laser Scanning and Remote Sensing, Univ. of Technology, Wien, Autriche
Terrestrial laser scanning of rock slope instabilities
Forecast ; Landslide ; LiDAR ; Mass movement ; Remote sensing ; Research technique ; Rockfall ; Slope ; Terrestrial laser scanning
Key insights into the use of terrestrial laser scanning (TLS) in rock slope investigations include : 1) the capability of remotely obtaining the orientation of slope discontinuities; 2) the possibility to monitor rock slopes which allows not only
, deformation tracking and change detection will significantly improve our understanding on how rock slopes behave and evolve. Perspectives include the use of new 3D sensing devices and the adaptation of techniques and methods recently developed in other
Fusion of multi-resolution surface (terrestrial laser scanning) and subsurface geodata (ERT, SRT) for karst landform investigation and geomorphometric quantification
scanning
A multi-method research design based on terrestrial laser scanning, GIS, geophysical prospecting (electrical resistivity tomography, refraction seismics) and sedimentology is applied to investigate enclosed karst depressions in an integrated way