Morphometrics of Second Iron Age ceramics - strengths, weaknesses, and comparison with traditional typology (original) (raw)
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Although the potential of geometric morphometrics for the study of archaeological artefacts is recognised, quantitative evaluations of the concordance between such methods and traditional typology are rare. The present work seeks to fill this gap, using as a case study a corpus of 154 complete ceramic vessels from the Bibracte oppidum (France), the capital of the Celtic tribe Aedui from the Second Iron Age. Two outline-based approaches were selected: the Elliptic Fourier Analysis and the Discrete Cosine Transform. They were combined with numerous methods of standardisation/normalisation. Although standardisations may use either perimeter or surface, the resulting morphospaces remain comparable, and, interestingly, are also comparable with the morphospace built from traditional typology. Geometric morphometrics also present the advantage of being easily implemented and automated for large sets of artefacts. The method is reproducible and provides quantitative estimates, such as mean shape, and shape diversity of ceramic assemblages, allowing objective inferences to be statistically tested. The approach can easily be generalised and adopted for other kinds of artefacts, to study the level of production standardisation and the evolution of shape over space and time, and to provide information about material and cultural exchanges.
Some Applications of Geometric Morphometrics to Archaeology
This work explores some aspects of the application of geometric morphometric techniques in archeology, with a focus on lithic artifacts. We show that Elliptic Fourier Analysis and landmark/semi-landmark based methods can easily generate quantitative useful information relative to outline variation in lithic artifacts. This information can be used latter as raw data into univariate, multivariate analysis to explore mayor trends of morphological variation as well as relations between metric and morphological variation.
Lecture Notes in Computer Science, 2014
Although the potential of morphometrics for the study of archaeological artefacts is recognized, quantitative evaluation of the concordance between such methods and traditional typology and the potential of these techniques as supported methodologies in the archaeological analysis is a pending task. We present a new method to characterize and classify wheel-made pottery by its profile, using Mathematical Morphology. Each piece is represented as a vector, obtained by sampling the so called morphological curves (erosion, dilation, opening and closing), and Euclidean Distance is used as a similarity measure. The proposed technique has been studied using a sample of 1133 complete ceramic vessels from the Iberian archaeological sites from the upper valley of Guadalquivir River (Andalusia, Spain), showing that it is compatible with the existing corpus, established by experts.
Although the potential of morphometrics for the study of archaeological artefacts is recognized, quantitative evaluation of the concordance between such methods and traditional typology and the potential of these techniques as supported methodologies in the archaeological analysis is a pending task. We present a new method to characterize and classify wheel-made pottery by its profile , using Mathematical Morphology. Each piece is represented as a vector, obtained by sampling the so called morphological curves (erosion, dilation, opening and closing), and Euclidean Distance is used as a similarity measure. The proposed technique has been studied using a sample of 1133 complete ceramic vessels from the Iberian archaeological sites from the upper valley of Guadalquivir River (Andalusia, Spain), showing that it is compatible with the existing corpus, established by experts.
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.
Matching sherds to vessels through ceramic petrography: an Early Neolithic Iberian case study
Ceramic re-fitting has traditionally focused on linking sherds to vessels using their formal features or decoration. This paper presents an innovative procedure designed to test such associations using ceramic thin section analysis. An assemblage of the earliest hand-made ceramics from central Iberia dated to the second half of the 6th millennium BC was used as a test case. First, the whole ceramic assemblage was subjected to macroscopic morphological sorting, taphonomic evaluation and a re-fitting operation. These tasks led to the recognition of both secure physical joins and probable matches. 16 sherds, representing 8 pairs, were selected from among those probable matches. These samples were investigated by thin section petrography and the photomicrographs processed using digital image analyses to produce qualitative mineralogical and quantitative textural data for assessing the likelihood of each pair belonging to the same vessel. The results show the potential of this strategy for matching sherds to vessels, as well as its reliability and wide applicability.
For archaeologists, metallic artifacts are key materials to assess Middle Bronze Age production areas and cultural exchanges. Here, a set of 629 bronze palstaves excavated in northern France, belonging to Breton and Norman typological groups, was treated by (open) outline-based morphometrics with orthogonal polynomial regression. Using robust statistics developed for outlier detection, these Norman and Breton palstave outlines can be divided into two groups: those for which the shape fluctuates close to the standard shape, called "congruent" axes, and those which are far enough from this standard to be considered as "non-congruent", although they possess most of the features of the typological group. The highest density of discovery (whether congruent and non-congruent in shape) is in the extreme east of Brittany for the Breton axes, while the Norman axes are concentrated in northern Normandy, hence the choice of names. However, the distribution of congruent and non-congruent artifacts appears to be spatially dependent for the Norman group, and to a lesser extent for the Breton group, as there are proportionally more congruent specimens inside the supposed production areas than outside. This contradicts the generally accepted archaeological scheme which hypothesizes that all axes in a group originate from the same production center, and that some items were exported from there to supply neighboring regions. Other minor production centers probably existed, copying the original model with greater shape variation.
Morphometric Analysis Applied to the Archaeological Pottery of the Valley of Guadalquivir
Ceramics are one of the most documented materials in the archaeological interventions. The documentation and the analysis of the pottery shapes allow the knowledge of the chronology and the functionality of the settlement where they have been found. The achievement of a typology of ceramic materials is made attending on different aspects (function, context, morphometry. . .). In this contribution a methodology of analysis of archaeological ceramic is showed. This methodoly is based on the technique of nonrigid deformable analysis applied to the drawing of the profile and is aimed at the construction of a ceramic typology.
A proposal of ceramic typology based on the image comparison of the profile
Ceramics are one of the most documented materials in the archaeological interventions. The documentation and the analysis of the pottery shapes allow the knowledge of the chronology and the functionality of the settlement where they have been found. The achievement of a typology of ceramic materials is made attending on different aspects (function, context, morphometry …). In this contribution a methodology of analysis of archaeological ceramic is showed. This methodology is based on the technique of nonrigid deformable analysis applied to the drawing of the profile and is aimed at the construction of a ceramic typology. This work is included on the CATA project (Archaeological Wheel Pottery of Andalusia in its acronyms in Spanish). The main objective of the project is the achievement of a reference collection accessible by Internet.The above-mentioned reference collection consists of a sample of 1,390 complete shapes corresponding to different chronological periods; from the seventh century B.C. until the fiftteenth century A.D., documented in the region of Andalusia. Also fragments of ceramic shapes have been compared with complete vessels to be associated to certain shapes. The morphometric analysis allows on one hand the evolution of the ceramic shapes across the different historical periods and the creation of typologic groups based on the similarity of the shape. On the other hand, the computerization of the archaeological ceramic data across Internet allows a uniform and standard ceramic analysis.
Ceramic re-fitting has traditionally focused on linking sherds to vessels using their features or decoration. This paper presents an innovative procedure designed to test such associations using ceramic thin section analysis. An assemblage of the earliest hand-made ceramics from central Iberia dated to the second half of the 6th millennium BC was used as a test case. First, the whole ceramic assemblage was subjected to macroscopic morphological sorting, taphonomic evaluation and a re-fitting operation. These tasks led to the recognition of both secure physical joins and probable matches. 16 sherds, representing 8 pairs, were selected from among those probable matches. These samples were investigated by thin section petrography and the photomicrographs processed using digital image analyses to produce qualitative mineralogical and quantitative textural data for assessing the likelihood of each pair belonging to the same vessel. The results show the potential of this strategy for matching sherds to vessels, as well as its reliability and wide applicability.