Articles | Volume 20, issue 5
Research article
10 May 2016
Research article |  | 10 May 2016

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

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

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 two-dimensional (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.

Short summary
This paper presents a novel approach that provides evidence of environmental conditions during the formation of a cave inferred from measuring the geometry of the cave surface. We focused on winding channels with associated cave landforms carved high up in the cave ceiling inaccessible to direct inspection by speleologists. This was possible by coupling 3-D laser scanning of the cave and analyzing the cave morphology by the tools used in 3-D computer graphics and digital terrain analysis.