3-D MAPPING TECHNIQUES FOR ENHANCING LOW ELEVATION / LOW GRADIENT DATA FOR GEOMORPHIC ANALYSIS: EXAMPLES FROM THE SC COASTAL PLAIN

A number of standard types of analysis are difficult and sometimes nearly impossible in areas of very low relief like the South Carolina Coastal plain. This paper looks at mathematical manipulations of the Digital Elevation data (Raster based DEMs) to enhance subtle features in the landscape. The enhanced maps allow analysts to better identify the geomorphic features that result from both the subsurface structures, and the surficial processes. The enhancements range from simple shaded relief effects to the application of exponential power series and spatial filters. Understanding the effects of the manipulations on the underlying data is essential to being able to use the new enhanced DEMs for analysis. These techniques when applied in the correctly to the data sets can be used to identify subtle watershed features, enhance lineaments for easier identification, they help the analysts to tell natural features from manmade ones. The techniques discussed work with both readily available USGS elevation data sets, as well as, higher resolution LIDAR data.