AGMT3-D: A software for 3-D landmarks-based geometric morphometric shape analysis of archaeological artifacts.

Abstract

We present here a newly developed software package named Artifact GeoMorph Toolbox 3-D (AGMT3-D). It is intended to provide archaeologists with a simple and easy-to-use tool for performing 3-D landmarks-based geometric morphometric shape analysis on 3-D digital models of archaeological artifacts. It requires no prior knowledge of programming or proficiency in statistics. AGMT3-D consists of a data-acquisition procedure for automatically positioning 3-D models in space and fitting them with grids of 3-D semi-landmarks. It also provides a number of analytical tools and procedures that allow the processing and statistical analysis of the data, including generalized Procrustes analysis, principal component analysis, a warp tool, automatic calculation of shape variabilities and statistical tests. It provides an output of quantitative, objective and reproducible results in numerical, textual and graphic formats. These can be used to answer archaeologically significant questions relating to morphologies and morphological variabilities in artifact assemblages. Following the presentation of the software and its functions, we apply it to a case study addressing the effects of different types of raw material on the morphologies and morphological variabilities present in an experimentally produced Acheulian handaxe assemblage. The results show that there are statistically significant differences between the mean shapes and shape variabilities of handaxes produced on flint and those produced on basalt. With AGMT3-D, users can analyze artifact assemblages and address questions that are deducible from the morphologies and morphological variabilities of material culture assemblages. These questions can relate to issues of, among others, relative chronology, cultural affinities, tool function and production technology. AGMT3-D is aimed at making 3-D landmarks-based geometric morphometric shape analysis more accessible to archaeologists, in the hope that this method will become a tool commonly used by archaeologists.