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

Abstract

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on twodimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

Combined Use of Terrestrial Laser Scanning and UAV Photogrammetry in Mapping Alpine Terrain

“…The DEM data structure reaches limitations in modelling pronounced verticality of land surface, which often occurs in rugged alpine terrain or in caves [51]. Therefore, we also generated a 3D vector-based surface model (i.e., polyhedral mesh) using the Poisson reconstruction [52] implemented in the Cloud Compare software.…”

Applying species distribution models to caves and other subterranean habitats

“…To correct for this mismatch manually, the topographic position of the ground plan of the cave has to be derived, in order to establish the correct position occupied by the species within the subterranean environment, and to project it to the surface. Sophisticated tools that permit georeferencing of the internal geomorphology of karst are available in the specialized literature (Florea et al 2002, Litwin 2008, Gallay et al 2016). However, the decision to spend time and invest funds to obtain very precise GPS coordinates rather than approximations will largely depend on the scale of the phenomenon under investigation.…”

TLS and SfM Approach for Bulk Density Determination of Excavated Heterogeneous Raw Materials

“…Generally, in the field of geosciences and mining industry, many studies deal with the issue of surface modeling. For example, Blistan et al successfully used UAV photogrammetry to model rock outcrops in the surface quarry also used in this research [17]; Gallay et al used the combination of TLS technology and digital 3D modeling for surface reconstruction to derive geomorphic properties of underground cave spaces [18]; Hofierka et al defined a workflow to process massive data from terrestrial and airborne laser scanning to derive accurate digital models representing surface and subsurface geomorphological features [19]; airborne laser scanning was also used to map and model slope deformations in a badly accessible terrain by Fraštia et al [20]; digital terrain models derived from LiDAR and UAV data were successfully used for safety, remediation, and ecological problems by Moudrý et al [21].…”