Beyond the Square Hole

Abstract

In archaeological excavations, two of the most critical pieces of information we record are the three-dimensional (3D) context and provenience of artifacts, samples, features, excavation units, excavation layers, and, in some cases, sites themselves. Accurate and precise recording of these data is imperative because spatial data become the core dataset from which archaeologists begin ABSTRACTThe accurate and precise collection of three-dimensional (3D) context and provenience data is of critical importance for archaeologists. Traditional square-hole methods are being augmented by new digital techniques to increase the accuracy and precision with which 3D data are collected. Structure from Motion (SfM) photogrammetry is an emerging digital technique that is becoming more widespread for collecting 3D data of archaeological sites and features. We are using handheld digital cameras and ground-based SfM to record accurate and precise 3D context and provenience data at the scale of the excavation unit and profile during rockshelter excavations in the Lower Pecos Canyonlands of Texas. By combining SfM with traditional excavation methods, we collect 3D data on excavation units, layers, features, and profiles without excavating in grid-bound square units. SfM provides a straightforward and flexible method to excavate based on the stratigraphy and logistical pragmatics, which further aids in assigning precise context and provenience to recovered artifacts and samples. This article describes how ground-based SfM serves as a basic recording tool during excavation and shows that, by applying ground-based SfM methods to excavation, archaeologists can collect more, and more accurate, data than with traditional square-hole methods.La colección exacta y precisa del contexto y de los datos de procedencia en tres dimensiones (3D) de objetos y rasgos es de importancia crítica para la arqueología. Los métodos tradicionales a base de unidades cuadradas están siendo aumentados por nuevas técnicas digitales que tienen el objetivo de mejorar la exactitud y la precisión con las que se recogen los datos en 3D. La fotogrametría de estructura a partir del movimiento (Structure from Motion; SfM) es una técnica digital emergente que está cada vez más generalizada para recoger datos en 3D de sitios y rasgos arqueológicos. Utilizamos cámaras digitales portátiles con SfM terrestre para registrar los datos en 3D exactos y precisos de contexto y procedencia a la escala de la unidad de excavación y del perfil durante las excavaciones de abrigos rocosos en los cañones del Lower Pecos, Texas. Mediante la combinación de SfM con los métodos de excavación tradicionales, recogemos los datos en 3D de unidades de excavación, capas, rasgos y perfiles sin excavar en unidades limitadas por una cuadricula tradicional. La SfM proporciona un método sencillo y flexible para excavar basado en la estratigrafía y las consideraciones prácticas, lo que ayuda aún más la asignación de contexto preciso y procedencia a los materiales culturales y muestras recuperados. En ...

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