RECREATING AN UPPER CRETACEOUS DINOSAUR ASSEMBLAGE WITH GIS SOFTWARE

CHADWICK, A. V., Dept of Geology,
TURNER, L. E., Dept. of Mathematics and Physical Sciences, Southwestern Adventist University, Keene, TX 76059;
SPENCER, L., EHRC, 4754 Carberry Ck. Rd., Jacksonville, OR 97530

Using ArcGIS 8.2, and data from digital photographs and high-resolution GPS coordinates of the bones we have recreated precise virtual maps of the distribution of all bones, bone fragments, ossified tendons and teeth in quarries operated in an extensive Upper Cretaceous (Lance Formation) bed in eastern Wyoming. The process of mapping the bones, photographing and georectifying over 2000 items has been a rich learning experience. Thanks to recent changes in the ESRI product, it is now possible to carry out this process without compromising data in the process.

The bones are field prepared and photographed and GPS data are retrieved in situ. The bones are then stripped from background using a "smart edge" feature in Paintshop Pro. The photos are converted to TIF files on a white background. The ArcMap module of ArcGIS is used to georeference the TIF file of each bones with the GPS data. When the bones have been rectified, they can be taken into the ArcScene 3-D viewer and examined in three space.

Because of continuing and as yet unexplored limitations in the number of layers displayable in the ArcScene viewer, we have found it convenient to group the bones in clusters by year or by bone type or elevation in the quarry to develop larger exported georeferenced assemblages of bones that can be treated as single layers in ArcScene. This allows us to break the data down and query with respect to distribution in vertical or horizontal space. As a consequence of applying these techniques to the taphonomic data, virtually all of the data with respect to location of the bones are preserved intact, and the assemblage can be visualized as it appeared in the ground. The finished files can be exported as VRML files for broad dissemination.

paper presented at the SVP 2003 meeting, St. Paul, MN, Oct 2003.