Kinsland and Wildgen (2006) presented 2D color-coded maps of the LIDAR (light detection and ranging) derived topography of the Prairie complex near Lafayette, Louisiana, identifying several topographic features including a Pleistocene Red River distributary system and several faults. We have since imaged the LIDAR-derived topography in a 3D virtual reality (3D VR) system developed in the Center for Advanced Computer Studies (CACS) at the University of Louisiana at Lafayette. With this system, we can interact with and interpret the data.

Figure 1 is an example of the data currently in the system. This image extends from very near the Gulf of Mexico on the south to the north of Opelousas, Louisiana (about 50 mi [80 km] north-south), and from the “coteau” (the scarp separating the Prairie surface from the Mississippi Valley) on the east to beyond the Mermentau River on the west (about 30 mi [50 km] east-west). Elevations range from nearly zero ft (0 m) in darkest blue areas to over 60 ft (20 m) in red. In this figure, several leveed distributary channels emanate from a Pleistocene Red River deltaic complex near Opelousas in the upper right of the image. Figure 2 shows one of these leveed channels interpreted within the interactive 3D system as being marked with several points. A volumetric lens (see description below), where the color scale used to code the elevation may be interactively adjusted to highlight particular features of interest, is positioned in the data in Figure 3. The topography of the leveed distributary channel is clearly imaged. In Figure 4, the volumetric lens has been moved and the color scale adjusted to image another leveed channel and the scarp of an east-west trending, down-to-the-south fault. The volumetric lens in Figure 5 is used to image tributaries of the present-day drainage system. Note that the imaged present-day drainage system is situated between the elevated levees of the Pleistocene distributary system. In fact, almost all of the present-day drainage is between the Pleistocene distributaries. Essentially, the only drainage within the distributary channels is from runoff between the levees on opposite sides of the channel.

These images (Figs. 3-5) are presented in such a way that one can evaluate the utility of the volumetric lens by comparing the image inside a 3D lens region with that of the adjacent data. Even in these 2D images, the features where the function of the lens has been interactively adjusted, are more definitively imaged than in the presentation outside of the lens.

Figure 1. Image of LIDAR topography data of the surface of the Prairie complex near Lafayette, Louisiana. The image is roughly 50 mi (80 km) in north-south extent and 30 mi (50 km) in east-west extent.