ini al conclusions and future projects the usumacinta river has
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Paths of Interac.on: GIS Spa.al Analysis in Preclassic Mesoamerica Omar Alcover Firpi, PhD Student-‐Anthropology Department
Brown University-‐ GEOL 1320 Introduc)on: Mesoamerica is a cultural and geographic area known for its wide diversity of civiliza.ons that spanned
from Northern Mexico down South to the borders of modern El Salvador and Honduras. In the middle of this territory, the ancient Maya civiliza.on flourished and developed. The emergence of socio-‐poli.cal complexity is linked with the establishment of plaza-‐pyramid complexes in southern Mesoamerica from as early as the Middle Preclassic Period (1000BC-‐700BC). Recent research suggests that plaza-‐pyramid complexes in early Maya centers, understood as public ritual spaces, came into being through par.cipa.on in larger interregional interac.ons with contemporary centers in Mesoamerica (Inomata et al. 2013). This study assess the role played by Preclassic Usumacinta River Valley sites regarding interregional interac.ons with contemporary centers, specifically that of the site of La Técnica, with the western most E Group of the Maya area, with its contemporary centers.
Research Objec)ves: The study incorporates GIS Spa.al Analysis to assess Least Cost Paths (LCP) between Middle Forma.ve Chiapas and Golf Olmec sites to that of the Maya site of Seibal, where clear interregional interac.ons are evidenced as early as 1000BC. Addi.onally Viewsheds were also calculated to assess the area of visibility of the La Técnica E group as well as visibility of the Least Cost Paths between the Olmec sites and Seibal. Considering the evidence of an E-‐Group assemblage at La Técnica, the study aims to verify if LCPS between MFC sites and Seibal pass through the Usumacinta River Valley sites that would account for the adop.on of this architectural assemblage at the site. Furthermore the study seeks to evaluate the role of La Técnica among contemporary Usumacinta Valley sites.
Methodology: The founda.ons for all the GIS spa.al analysis presented in this study are based on an SRTM Digital Eleva.on Model (DEM) with 90m resolu.on. The SRTM DEM was projected to the UTM Zone15N coordinate system. Furthermore, the shapefiles of the sites were acquired and projected to the same coordinate system as the DEM. Once all the data was cleaned and organized, LCPs were calculated, independently, star.ng from La Venta, San Isidro and Chiapa de Corzo towards Seibal (see map below). Addi.onal LCPs were created star.ng from La Técnica to Seibal and La Venta and other contemporary Preclassic sites within the Usumacinta River valley (see A, B and C). It is important to note that the LCPs only take into account difficulty of human travel in varying slopes through change in eleva.on (see Doyle et al. 2012). Rivers, causeways, and other natural and manmade paths were not considered in this study. Viewsheds were calculated for selected Preclassic Usumacinta River Valley sites, also based on the SRTM DEM.
Discussion of Results: If we observe maps A, B and C we can appreciate that the LCPs from the MFC and Golf Olmec sites completely avoid La Técnica and its contemporary Preclassic Usumacinta Valley sites. Addi.onally, the viewsheds from the Preclassic Usumacinta sites do not coincide with the LCPs outside of the valley. This would ini.ally suggest that the Preclassic sites in the Usumacinta River Valley were not near the most probable exchange route between larger Preclassic centers, thus may not have a significant role in these cultural exchanges. In fact, it is important to consider that the LCP from La Técnica to La Venta (yellow) and Seibal (dark blue) deviates from the larger path between MFC and Seibal. This does not imply, though, that sites in the Usumacinta River were unaware of cultural and architectural developments outside of the valley (inferred by the Preclassic E group at la Técnica). Another interes.ng result, as observed in maps B and C, is that the northwest LCP from La Técnica to Rancho Bufalo (the western most Usumacinta site in this study) passes through or near contemporary centers, excluding Macabilero and Na Witz. These Preclassic Usumacinta sites have not yet been systema.cally studied, yet due to the evidence of the most probable foot paths between them it would be interes.ng to consider similari.es and longevity in occupa.on between them. If we look above at map B, we can appreciate that none of the viewsheds between these centers are totalizing, limited to various kilometers from the site center, thus no site had complete visibility of the valley during this .me period.
Ini)al Conclusions and Future Projects The Usumacinta River has been populated by the Maya as early as the Middle Preclassic Period (1000BC-‐400BC) and its occupa.on spanned un.l the Classic period (AD250-‐AD900), marking a long tradi.on of shids in civic planning and rituals (Golden et al. 2006). Middle Preclassic seflements along the Usumacinta are characterized by diverse civic planning that represents selected features of larger architectural assemblages popular at the .me, possibly poin.ng to specific ritual ac.vi.es taking place at each site. Serving as complementary ritual centers, sites along the Usumacinta present a different view of society in the past, diverging from models that emphasize single monumental sites as the driving force in ritual and poli.cal complexity. The rela.ve distance from the most probable paths of exchange between MFC sites and Seibal support the theory of Usumacinta sites’ rela.ve isola.on and divergent path in Socio-‐Poli.cal complexity. Furthermore, LCP within the Usumacinta Valley pass through many Preclassic centers, sugges.ng a link between these centers that is yet to be determined. I would argue that that limited visibility of each site within the valley may suggest that no site had overarching control over the valley, a theory that Golden and Scherer (2013) have suggested. Doyle (2012) has suggested that E-‐Groups at Central Petén sites are located on prominent hill-‐tops with extensive viewsheds. The limited viewshed of the E-‐Group at La Técnica contrast this. Although data is very much limited I would argue that the E-‐Group at la Técnica, due to difference in height loca.on at the site, may have had a different func.on for people at the Usumacinta Valley. GIS spa.al analysis have allowed to further refine research ques.ons and points of interest that would have otherwise would have been inaccessible due to monetary and .me constraints. Further LCP and Viewshed analysis of the Usumacinta River Valley will take into considera.on the probable vegeta.on at the .me and the difficulty of river crossing.
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