LiDAR — Light Detection And Ranging — has been in the news as an accurate and detailed image-generating technology that can reveal long-lost archaeological sites. LiDAR data has allowed researchers to locate immense sites hidden in the lush forest, among them Terraces at Caracol, major temples in Honduras, and now a city of grand proportions in Cambodia.
These discoveries are important, but the continuing challenge with LiDAR data is to understand the subtlety and the nuances of the landscape.
At El Pilar in Belize and Guatemala, most of the major architecture has been mapped by traditional archaeological survey methods. It is here where we are using LiDAR to understand the land-use patterns of the Maya houses and forest gardens that were so important to the city’s prosperity.
With a generous donation of LiDAR data from Mayaniquel/Anfield Nickel that covered the 8 square miles of the binational El Pilar Archaeological Reserve for Maya Flora and Fauna, we used raster elevation models to scrutinize the imagery of the areas surrounding major monuments. This is the perfect project in which to develop the field strategies for this novel technology. We can highlight targets on the LiDAR image and use the Global Positioning System (GPS) to validate the location in the field.
We began our work the end of April and within a month had an initial review of the core area of El Pilar. Using our survey maps of the residential zones and LiDAR models, we were able to identifiy areas for survey with coordinates that we plugged into our GPS units. Crews specializing in terrain and vegetation led by Hugo Bihr of the elite school ESGT in Le Mans, France, were followed by crews focused on archaeology with Guatemala specialist Paulino Morales. Centering on these targeted areas, we worked to refine our methods and interpretations of the imagery.
Our international team combed 140 hectares around the monuments to determine the nature of cultural and ecological features and clarify characteristics that came from the image processing. As we initially reviewed our spatial models, the large structures were obvious. We discovered a magnificent citadel in the east, accurately located mapped temples that were on the peripheries, and detected the configuration of the offset causeway that links both monumental complexes and both countries. The remarkable accuracy of the LiDAR data allowed us to update our mapping records to reflect the precise locations of each architectural monument.
The most significant results are the details in LiDAR detection that focus on small remains of Maya housing settlements. These remnants of Maya life indicate how the Maya affected the landscape. Ancient Maya house sites were identified as formal and informal groups on hilltops, elevated on plazas and adjacent to major quarries on sides of hill slopes. Everywhere there are trees that mark the useful composition of the Maya forest: copal, allspice, chicozapote, ramon, corozo, cedar and mahogany. As an added bonus, on top of the utility and practicality of the forest lies beauty and wonder in a drapery of vanilla orchids.
A particularly interesting discovery was the intricacy of water management features. We found a number of rock alignments directing water and terraces that would slow water across slight slopes. The water features used the natural topography to accentuate water movements, taking advantage of water flow. We also identified a sunken plaza construction that links the major causeway. There is a small ball-court like plaza elevated in the midst of this sunken feature. These revealed structures are unique features of the El Pilar site and raise questions as to their use and meaning within the ancient Maya culture.
At each location we itemized the local trees, recorded the nature of the terrain, and listed the nature of the canopy and understory to compare with the LIDAR data itself. This information is now being compiled into our Geographic Information System at UC Santa Barbara known as the Maya Forest GIS. From these data we will be able to use LiDAR technology to compare and contrast field verification of cultural characteristics, natural features and vegetation. These methods will also give us a better understanding of how we can use LiDAR in our future field projects. While you can see much in the LiDAR images, the reality of walking on the ground brings everything together.
— Anabel Ford Ph.D. is the director of UC Santa Barbara’s MesoAmerican Research Center and president of Exploring Solutions Past. Ford, UCSB’s resident expert on Maya archaeology, discovered the ancient Maya city-center El Pilar, which bridges Belize and Guatemala. By decoding the ancient landscape around El Pilar, she is creating a sustainable model in conservation and agriculture that can regenerate the threatened Maya forest. With investment and support, her model can assist environmental efforts worldwide. Click here for more information on El Pilar. Click here to read previous columns. The opinions expressed are her own.