Blog Archives - Page 7 of 7 - Plaza of the Columns Complex

Looking for traces of the past: interpreting the surface of the Teotihuacan Valley

January 4, 2018 Mariela Perez Comments 0 Comment

During the 2017 field season, the Plaza of the Columns Project used a special type of investigative tool called LiDAR (Light Detection and Ranging) to verify archaeological features out in the field. This method of remote sensing integrates GPS technologies, Inertial Measurement Unit, and lasers in order to collect altitudinal data. The combination of these sources help to define the surface of the terrain by generating digital elevation models (DEM) for us to further interpret and analyze.

In general terms, this technique allows us to recover traces of the past, either pre-Hispanic, colonial, or historical, which today are reflected in cultivated terraces, mounds or artificial elevations, and jagueyes or water reservoirs.

These features are blurred in what are now nopaleras (terrain covered in the nopal or cactus plant), agricultural fields, or even modern day villages. But thanks to this surveying method, one can outline the dimensions and proportions of architectural or hydraulic features of the past.

Coexistence with the settlers

While surveying the area, we have had the pleasure to interview landowners and gather historical information of past populations. They recalled early childhood stories told by their parents or grandparents about the foundation or organization of their communities since the beginning of the 20th century.

In addition to sharing their experiences, they provided information on the elements that we recognize today in LiDAR images. For example, in the town of Ixtlahuaca in the municipality of San Martin of the Pyramids, interviewees Juan Guillermo Castro, Pablo Rivero, Alejandro Hernández Ramirez, and Sebastián Medina shared stories when the only accessible water was from the water reservoir located in the center of the village. They also recalled the time when this part of the valley belonged to the Hacienda of Cerro Gordo. Other interviewees, Genoveva Diaz Alba with her daughters Lidia and Maria del Carmen Delgadillo Diaz, told us that her husband decided to modify the terrain in the 1970s in order to better cultivate it.

In addition to plentiful stories, some locals were highly generous and went over and beyond. Mr. Filemon Macías Juárez of San Lorenzo Tlamimilolpa not only granted us permission to visit his land but also donated a collection of ceramic materials that he collected throughout his lifetime. This allowed us to increase our comparative sample with late materials and correspond them to the Postclassic occupation of the region.

The enthusiasm and cooperation of the landowners are a result of the clear and transparent management of our objectives. Often times, the locals are contacted by other institutions with much less cordial terms. Therefore, we feel committed to establish clear communication and respect. We want them to feel informed and involved, whether by asking them to personally see the work we do, responding and explaining any personal doubts or observations, or adjusting to their needs and availability.

Acknowledgements

It is important to highlight the support provided by the municipal and auxiliary authorities of Ixtlahuaca and Santa Maria Palapa in the municipality of San Martin of the Pyramids. We also thank San Juan Teotihuacan in the Barrio de Purificación, San Sebastián Xolalpan, San Francisco Mazapa, Santa Maria Coatlan, and San Lorenzo Tlamimilolpan. Lastly, we gives thanks to private organizations such as the Animal Kingdom Zoo.

Teotihuacan: City of Water, City of Fire

September 9, 2017 Teresa Hsu Comments 0 Comment

Interested in seeing Teotihuacan artifacts? Come visit the new exhibition Teotihuacan: City of Water, City of Fire at the de Young Museum in San Francisco, California (September 30, 2017 – February 11, 2018). Can’t make it, or simply want to learn more? Check out the catalog for this exhibition where you can read chapters written by our very own PPCC co-directors.

Virtual 3D Animal Bone Models

June 25, 2017 Megan Sorrel - George Mason University Comments 1 comment

Zooarchaeology is a field within archaeology that seeks to answer questions about past human occupation and their environment through the study of animal remains¹. In practice, this means that a zooarchaeologist must be an expert in identifying animal bones. However, animals come in diverse shapes and sizes. How can someone develop expertise in such a broad field?

Having a comparative reference collection is key for understanding and formulating distinct patterns among differing species. And this is where I come in. I have just finished a project that helps lay the foundation for zooarchaeology students to build their proficiency in bone identification. Over the last four months, I have created a series of virtual three-dimensional models of deer bones. Everything from a deer’s cranium to the phalanx (or toe bone) is captured in this digital collection. Below you can explore some examples of these models:

Deer Assemblage by msorrel on Sketchfab

So, how do you even start to create a 3D model? Well, it starts with taking dozens of photos of each bone element. I then loaded the photos into a program called Agisoft’s Photoscan which “stitched” them together; by taking multiple photos from different angles and views, the program was able to compile these series of two-dimensional images and transform them into virtual 3D models. After the deer bones were modeled, I uploaded them onto Sketchfab, a website that allows users to display, embed, and share 3D models online. Sketchfab is particularly helpful for this project because it allows students to view the models on smartphones, tablets, and computers alike. It also has the feature to place annotations within each model, as evidenced by the standard measurements and points included on each bone.

I will find out this summer how these models work in practice, for several students from George Mason University (GMU) are flying to Mexico to examine animal remains in the field as part of the Project Plaza of the Columns Complex (PPCC). I spoke with one of the students, Leila Martinez, about how she has prepared for this challenging task of traveling and working without a deer comparative and how she thinks 3D models might help her this summer.

According to Leila, learning zooarchaeology requires extensive hands-on study of bones. With the absence of physical bones in hand, students often rely on animal bone manuals, though these often contain hand-drawn images from few static views. She believes that 3D models may make bone identification easier by letting students interact with realistic images. While 3D technology will never be able to replace the direct tactile experience of working with real bone, in time, these 3D virtual reconstructions could rival traditional reference books. After all, books are bulky and often times expensive, and a digital skeletal collection can be easily transported and manipulated all by the swipe or click of a finger.

Students coming to Teotihuacan for zooarchaeological fieldwork can be an exciting and perhaps a little apprehensive experience, especially when one doesn’t know what to expect when joining the PPCC team for the first time. Is there a skeletal reference collection I can use? How complete is it? In what state are the bones I will be analyzing? Several GMU students like Leila and me already have firsthand experience handling bone with cleaning and labeling the many (or shall I say thousands of) animal remains in our Archaeological Sciences lab. Although real world archaeological assemblages are surely more complex with fragmented, commingled, and/or missing bones, I know the hard work I put into preparing these models of complete bones will help zooarchaeologists to confidently identify the specimens they encounter. Creating virtual 3D reference models is a time-consuming endeavor, but in the end I expect these easily transportable, full of detail, and user-friendly products will play a much larger role out in the field than anticipated.

References

1. Steele, T. E. 2015. The Contributions of Animal Bones from Archaeological Sites: The Past and Future of Zooarchaeology. Journal of Archaeological Science 56: 168–176.