Using measures of cost distance in the estimation of polity boundaries in the Postclassic Yautepec valley,Mexico

The reconstruction of polity boundaries is essential for the study of political evolution, but few enhancements to archaeological boundary estimation methods have been proposed in recent years. New techniques of terrain modeling and geographical analysis provide the means to augment traditional methods of boundary estimation. In this paper, I review archaeological methods for estimating the spatial location of boundaries between independent polities and ways to modify these methods to explore the processes of political expansion in the evolution of complex societies. I demonstrate several of these methods using data from Postclassic polities in the Yautepec valley, Morelos, Mexico. Through time, seven independent polities were founded, expanded, and were ultimately incorporated within two levels of regional political administration. I apply new quantitative methods for the estimation of polity territories and explore the processes that resulted in the formation of a regional polity. The resulting boundaries are objective estimates of the location of borders based on energetic efficiency that can be systematically tested against theoretical models. These estimated boundaries provide a basis for exploring the social meaning of territorial divisions. Additionally, energetic boundaries provide a means for delineating local zones for landscape utilization and comparative analyses.