INVESTIGATION OF LIDAR FOR GEOMORPHOLOGICAL MAPPING: A WEST VIRGINIA CASE STUDY

The aim of this project was to investigate the potential of light detection and ranging (lidar) data sets to support geomorphological investigations. The traditional source of elevation information is from photogrammetric sources, and although generally of coarse resolution, is widely available. Lidar is a relatively new technology for generating high-resolution elevation maps of the earth’s surface. The most easily accessible format of lidar is gridded raster data; however, the process of interpolating from the quasi-randomly spaced lidar point data may result in the removal of important fine scale geomorphological features.

High resolution lidar and color aerial imagery collected on behalf of the US Army Corps of Engineers of the Lower New River Gorge in West Virginia was the primary data set for this project. This data set was compared to a 3-meter posting photogrammetrically derived DEM of the same area.

In the initial analysis, both the lidar point data and derived gridded digital elevation models were explored. Maps showing the topography and the bedrock contacts of the study site were generated. Shaded relief maps from the digital elevation data sets were generated to enhance subtle topographic features that are important for geomorphic analysis and compared to the original point data. A 3-dimensional fly-through of the study site was also generated using Erdas Imagine Virtual GIS to facilitate interpretation of the geomorphology of the area, and to compare the information content of the data sets. The photogrammetric DEM had considerably less spatial detail as compared to the lidar data set, which limited its value for geomorphological interpretation. The lidar DEM had much more detail; however, it was missing features that were originally available in the point data. The point data are limited by the challenge of visualizing the geomorphic surface of area.