LIDAR IMAGERY EMPLOYED IN CAROLINA BAYS RESEARCH

Photographs of the Carolina bays have been available from the air since the early 1930’s. Those early images sparked extensive research into their genesis, but they reveal only a small part of their unique planforms. Digital elevation maps (DEM) created with today’s Laser Imaging and Range Detection (LiDAR) systems accentuates their already-stunning visual presentation, allowing for the identification and classification of even greater quantities of these shallow basins across North America.

Our research was enabled to a large part by the facilities and satellite imagery of the Google Earth. The Global Mapper GIS application was used to generate LiDAR images for visualization on the virtual globe, using DEM data from the United States Geological Survey and the Nebraska Department of Natural Resources.

Using these facilities, a survey was undertaken to catalogue the extent of Carolina bays, indexed as localized “fields”. Estimations of the bays’ numerical quantity extends into the hundreds of thousands, therefore no attempt was made to identify all such landforms; instead each field was selected to be rigorously representative of the distribution in a given locale. The data is primarily used in a geospatial analysis, attempting to correlate the bays' orientations in a triangulation network.

Identifying Carolina bays on the costal plain is straight forward, given their solid identification, however bay planforms tend towards a circular presentation in the northern and southern extremes of their geographic extent, presenting challenges. Also challenging is the rougher terrain seen when moving inland. We suspect that access to high resolution LiDAR DEMs in more regions would aid in expanding the bays’ identified range.

While there is much research discussing Carolina bays in the east, there are significant quantities of aligned, oval basins in the Midwest. These basins are aligned SW ➔ NE, and are considered to be vital components of the triangulation network.

The survey resulted in a catalogue of ~250 fields of Carolina bays (representing many thousands of individual bays), managed in a Keyhole Markup Language metadata file. The catalogue of LiDAR images is available for interactive visualization on Google Earth's virtual globe using the file available at http://cintos.org/Distal_Ejecta_Fields.kmz .