Geomorphometric analysis of cave ceiling channels mapped with 3D  terrestrial laser scanning

Gallay, Michal; Hochmuth, Zdenko; Kaňuk, Ján; Hofierka, Jaroslav

doi:10.5194/hess-2016-74

Cited by 7 publications

(10 citation statements)

References 30 publications

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“…Fluviálna geomorfológia predstavuje veľmi dynamickú a vo svete rozvinutú výskumnú oblasť geomorfológie. Geomorfológia, ako vedná disciplína, sa postupne mení z opisne chápanej na procesne orientovanú vedu, ktorá zdôrazňuje nové a moderné geomorfologické koncepty, ako aj používanie kvantitatívnych metód a spôsobov priestorového zberu dát (Jain et al 2012, Gallay et al 2015a Gallay et al 2016b. Nevyhnutným predpokladom pre procesne orientované chápanie krajiny je získavanie presných modelov a dát s vysokým rozlíšením (James a Robson 2012 a Westoby et al 2012).…”

Section: úVodunclassified

Využitie UAV technológie pre klasifikáciu a mapovanie krajiny vo fluviálnej geomorfológii

Rusnák¹,

Sládek²,

Kidová³

2018

geogrcas

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Using UAV technology for landscape classification and mapping in fluvial geomorphologyThe aim of this paper is to present the possibilities of UAVs (Unmanned Aerial Vehicles) as photogrammetry payload carriers for data acquisition and fluvial landform identification and mapping. The manual and automatic classification of the Belá River riparian zone for landscape object identification and the analyses of the point cloud density after vegetation filtration was performed. The HEXAKOPTER XL including the Sony NEX 6 camera with 16 -50 mm lens for landscape monitoring features was used. Data was processed in Agisoft PhotoScan software. The RMSE (root mean square error) of aligned images was 60.121 mm (x coordinate), 43.7584 mm (y coordinate) and 29.46 mm (z coordinate). The resulting point cloud was semiautomatic classified in the software Terrasolid -Terrascan (Microstation), in the following six classes: high vegetation (over 5 m), medium vegetation (from 1.5 m to 5 m), small vegetation (from 0.2 m to 1.5 m), topographic surface and water surface. Orthophotomosaic was classified in ArcGIS software by supervised Maximum Likelihood Classification (MLC). Here training site signatures identified the five land cover categories (water area, bar surface, vegetation, Large Woody Debris -LWD and bare surface). The classification of photogrammetric derived point clouds increases the accuracy elevation model, but on the other hand, does not capture the real terrain and topography under the vegetation.

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Section: úVodunclassified

Využitie UAV technológie pre klasifikáciu a mapovanie krajiny vo fluviálnej geomorfológii

Rusnák¹,

Sládek²,

Kidová³

2018

geogrcas

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“…For 3D reconstruction and rock structural analysis, processing the full-resolution scan is not computationally efficient [5]. Therefore, the E57 format point cloud dedicated for these applications was decimated by sampling every seventh point to optimize processing time based on the suggestion of Ref.…”

Section: Point Cloud Processingmentioning

confidence: 99%

“…Therefore, the E57 format point cloud dedicated for these applications was decimated by sampling every seventh point to optimize processing time based on the suggestion of Ref. [5]. In CloudCompare [20], a free and open source software, the decimated scans were merged to provide a single discontinuous point cloud of the cave.…”

Section: Point Cloud Processingmentioning

confidence: 99%

“…Today, sophisticated light-scanning (or laser-scanning) sensors that are capable of collecting several thousands to million points per seconds have taken over from the traditional methods, delivering caves in their true 3D geometry at unprecedented level of accuracy [5]. Terrestrial laser scanning (TLS) survey has proven positive results in different applications such as archaeological investigations, 3D modelling and visualization, geomorphological analysis, passage stability and risk assessment, biological inventory and so on.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Macro- and Micro-Geomorphology of Cave Channel from High-Resolution 3D Laser Scanning Survey: Case Study of Gomantong Cave in Sabah, Malaysia

Idrees¹,

Pradhan²

2017

Cave Investigation

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Three-dimensional documentation of hypogene cave morphology is one of the major applications of laser scanning survey. This chapter presents applications of terrestrial laser scanning (TLS) survey for analyzing endogenic cave passage geomorphologic structure and morphometry using 3D meshing, high-resolution 3D texture modeling for geovisualization, and its potential for cave art documentation. To achieve this, multiscale resolution 3D models were generated; one using the mesh model for macro-morphological analysis and the other with the full-resolution scan to produce high quality 3D texture model for identification of micro-morphological features. The mesh model of the cave makes it possible to analyze the general shape, distinguish phreatic tube from post-speleogenetic modified conduits and carry out morphometric measurements including the cave volume and channel surface area. The 3D texture model provides true to live visualization of the cave with exceptionally high level of accuracy and details that would be impossible to obtain with direct observation by visiting the site or from the mesh model. The model allows discerning different speleogenetic phases, karstification processes and micro-morphologies such as wall and ceiling seepage, hanging rocks, fractures, scallops, ceiling flush dome, pockets, bell-hole and avens. Also, the texture model permits identifying cave arts and engravings along the passages

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“…Challenge for future research remains in distinguishing multiple hierarchies of landforms by using the high-resolution DEM or the original point clouds. For the complex topography and considerable vertical dissection, advantages of a 3-D mesh surface can be exploited for terrain modelling as [15] demonstrated in a cave.…”

Section: Discussionmentioning

confidence: 99%

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Supplemental Information 1: Digital Elevation Model and Mask of the Area of Interest

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The alpine landscape is rugged, dominated by glacial morphogenesis, comprising specific landforms of different sizes and shapes with a marked vertical relief and hierarchical-ordering of the forms. Digital geomorphometric analyses of such a land surface in a high level of detail can exploit mainly data acquired by airborne laser scanning or photogrammetry. However, the level of detail captured is limited to several meters or decimetres in these datasets for the relatively high above ground flying heights. Terrestrial laser scanning (TLS) and close range photogrammetry generate 3-D point clouds of ultra-high spatial resolution but their application is limited by extreme environmental conditions. TLS data often contain data shadows in alpine landscape resulting in inhomogeneous spatial distribution of the acquired 3-D point cloud. Such data properties cause creation of overly smoothed surfaces or artefacts in digital elevation models (DEMs) interpolated into a grid (raster). The sub-horizontal field of view in TLS can be compensated by sub-vertical field of view of digital cameras installed on unpiloted aerial platforms (UAVs). Such a photogrammetric 3-D reconstruction of terrain with UAVs is based on structure-from-motion (SfM) image matching techniques. The measurement precision and accuracy of UAV-SfM is lower than with TLS but the UAV-SfM data can be used in filling the TLS data voids. In this paper, we present the results of combined use of TLS and UAV-SfM for high-resolution modelling of a glacial cirque in the Tatry Mountains, the Carpathians, Europe. The achieved accuracy (1 standard deviation) of mutual co-registration of 18 TLS positions was 4.2 mm. The accuracy of georeferencing the final TLS data in the national cartographic system was 33.2 mm based on 15 ground control points. The UAV-SfM dataset was spatially coregistered on the TLS dataset with the accuracy of 137 mm and point filling the TLS voids were used to generate the final DEM of 0.5 m cell size from the combined point clouds.

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Geomorphometric analysis of cave ceiling channels mapped with 3D terrestrial laser scanning

Cited by 7 publications

References 30 publications

Využitie UAV technológie pre klasifikáciu a mapovanie krajiny vo fluviálnej geomorfológii

Využitie UAV technológie pre klasifikáciu a mapovanie krajiny vo fluviálnej geomorfológii

Characterization of Macro- and Micro-Geomorphology of Cave Channel from High-Resolution 3D Laser Scanning Survey: Case Study of Gomantong Cave in Sabah, Malaysia

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