Meeting Abstract
P3.131 Thursday, Jan. 6 ArcOSAUR: ArcGIS Operations for Surface Analysis Using Rasters CARNEY, Ryan M; Brown University ryan_carney@brown.edu
The advent of 3D digital scanning in the biological and paleontological sciences has provided powerful new tools for studying morphology, and has fostered the exaptation of complementary digital methods from the entertainment industry (i.e., 3D modeling and animation software) and geosciences. Recently, geographic information system (GIS) software has been used to characterize fossil morphology, although this has been limited to relatively planar manifolds (occlusal surfaces of mammalian teeth) and Euclidean geometrics (distance, slope, and orientation). In order to conduct more comprehensive morphologic analyses using ArcGIS software, a suite of automated processing tools called ArcOSAUR was created using the ModelBuilder visual programming environment. The ArcOSAUR toolbox allows for 3D datasets to be converted from computer-aided design (CAD) formats to triangulated irregular networks (TIN) and digital elevation model (DEM) rasters. In addition to calculating surface relief and basic Euclidean measurements, the tools can be used to analyze surface convexity and concavity, identify and characterize topographic landmarks, and even reconstruct 3D surfaces from 2D photographs. Additionally, analyses need not be limited to planar surfaces: various trigonometric operations provide for the identification of centers and axes of rotation along curvilinear joint surfaces; in turn these markers can be exported for use as kinematic references in modeling software. To illustrate the utility of these processing tools, forelimb elements of alligator Alligator mississippiensis, theropod Deinonychus antirrhopus, and pigeon Columba livia were digitized with a high-resolution laser scanner and reconstructed using Maya modeling software. ArcOSAUR was then used to import and process the 3D datasets, analyze the morphology of articular surfaces, and reconstruct cartilaginous tissue for D. antirrhopus using extant phylogenetic bracketing.
