LIDAR LANDFORM CHARACTERIZATION STUDIES IN WESTERN NEW YORK STATE

Lidar imagery with a resolution approaching 5-10 cm provides order-of-magnitude improvements in the ability to identify and accurately characterize landform elements in the meter to sub-meter range. Rapid and accurate discrimination of morphogenetic landforms and landform boundaries is possible over large areas that would take months of fieldwork to accomplish much less reliably with stereographic aerial photography, existing 10 to 20-foot interval topographic maps, or first generation DEM products. Features as small as plow furrows in agricultural areas are readily apparent. Studies of the morphology of late Wisconsin and Holocene landscapes clearly provide new and more revealing evidence of the dominant and active processes involved in landscape evolution and modification. A quadrangle-scale study area in western New York reveals that small-scale landslides and slumping in the glacial overburden along the sides of moderate-sized valleys are much more pervasive processes than might be assumed from studying even the most detailed topographic maps or aerial photographs. Such relatively small mass wasting features are commonly observed during field reconnaissance and mapping, but probably receive less attention than they deserve as active and pervasive landscape elements and determinants of slope angle. Such lidar imagery permits more accurate and precise identification and mapping of features such as moraines, outwash surfaces, subtle terraces, and small ice-contact landforms that could be overlooked by more conventional mapping techniques. ArcGIS© manipulation to create detailed contour maps, colored and shaded relief maps at variable sun azimuths and elevations, or slope maps, along with an ability to accurately compare discrete elevation differences all add a further dimension to the value and accuracy of this technique as applied to surficial mapping studies. Given the level of detail possible at such high topographic resolution, the technique has great promise in the quantification of geologic processes that would not be possible across such large areas with the same degree of accuracy within a reasonable time frame. It is clear that lidar-based studies of landscapes and small-scale landforms will become the method of choice and standard for accurate engineering or geologic studies.