Changing Olmec trade routes understood through Least Cost Path analysis

Abstract

This paper uses Least Cost Path (LCP) analysis to explore travel routes between the Gulf Coast and Soconusco regions of Mexico. LCP results are compared between the two regions during the late Early Formative period (1400-1000 cal BC) when San Lorenzo was the largest Olmec center on the Gulf Coast and the Middle Formative period (1000-400 cal BC) when La Venta replaced it. We contrast the well-known Tobler Hiking Function and the less well known Anaya Hernandez method to determine the LCP routes for each period as well as to calculate changes required to make the voyage as one Gulf Coast center eclipsed the other. We compare LCP models with changing locations of political centers and with colonial-period accounts of actual travel through the region that allows us to infer the logic of Olmec era trade networks. Methodologically, we show how the Anaya Hernandez friction values for LCP analysis are more appropriate for mountainous environments as they more reliably model the importance of slope than the Tobler Function does. Substantively, we demonstrate how important population centers were located along LPC routes. Further, that beginning during the Middle Formative period there were more connections to the highlands of Chiapas and Guatemala than in earlier times.