Dissertation Abstract

Geovisualization, rock weathering, and 3D laser scanning in the context of rock art preservation

Rock art, including petroglyphs and pictographs, is an invaluable remnant of past cultures.  Because it is, by definition, on rock, this cultural resource will ultimately disappear as its host rock weathers.  The identification, density, and condition of weathering features such as fissures, textural variations, weathering rind erosion, and tafoni – all major indicators of rock instability – play a key role in decisions regarding which rock art panels are in greatest risk.  A critical step towards rock art preservation is to develop an objective system for the classification and ranking of rock art panel’s likelihood for decay, disintegration, or collapse.

For the study described in this document, exposed rock panels in Colorado and California were scanned with a terrestrial light distancing and ranging (lidar) scanner.  Laser scanning facilitates isolating rock panels’ surface characteristics by structure, texture, laser intensity, and color.  Various interactive techniques, such as dynamic linking, brushing, probing, and conditioning serve to guide in the precise identification and mapping of weathering forms, which indicate surface instability.  My approach blends computational, cartographic, as well as visual methods, and utilizes geographic information science (GIS) and remote sensing software familiar to most physical geographers. 

The techniques for surface instability mapping and ranking in my research are non-invasive, quantitative, and transferable to any lithology.  Results indicate that rock art panel preservation decisions can be made with heightened confidence knowing that the instability ranking process is based on a rock weathering expert’s interaction with precise, high-resolution, geospatial data, collected from rock art panels.

Contributions of my work extend beyond rock art preservation: This research lays the groundwork for novel approaches to stone monument preservation, concrete condition surveying, and rockslope hazard mapping.  Contributions of the work to GIScience include one significant demonstration of a novel technique integrating various geographic information technologies and multivariate data exploration with geomorphological research.  Contributions of the work to geomorphology include an opportunity to elucidate the spatial relationship between weathering forms and independent variables such as slope, aspect, and insolation regimes.

Brandon Vogt - March 2007