Terrestrial laser scanning and exploratory spatial data analysis for the mapping of weathering forms on rock art panels

Abstract

Rock art conservators are faced with complex decisions to prioritize rock art panels for protection from destructive forces of weathering. We provide a system to facilitate such decision making that blends traditional remote sensing with interactive techniques of exploratory spatial data analysis. Our system, ‘mapping weathering forms in three-dimensional (3D)’ (MapWeF) uses a 3D laser scanning device for sub-centimetre data collection from in situ rock surfaces. After image and digital surface model processing, key rock weathering forms are highlighted through classification. Supervised classification builds training classes as a user probes known weathering forms. Guided by these training classes, the user then interactively brushes and assembles pixels from scatter plots until the user is confident that all manifestations of a particular weathering form have been mapped. The purpose of MapWeF is to construct detailed maps that highlight regions of decay on rock art panels. These maps can help rock art conservators take action on panels in need of urgent preservation or remediation.