The use of airborne mapping lidar (Light Detection and Ranging), a.k.a airborne laser scanning (ALS), has had a major impact on archaeological research being carried out in Mesoamerica. Since being introduced in 2009, mapping lidar has revolutionized the spatial parameters of Mesoamerican, and especially Maya, archaeology by permitting the recovery of a complete landscape and settlement pattern for further analysis. However, like any new technology, there are learning curves to be overcome, resulting in a feedback relationship between the on-the-ground archaeologists, the virtually grounded computer analysts, and the instrument designers. Archaeologists have been able to identify problems and issues with data production and visualization for the determination of archaeological remains caused by vegetation, special terrain conditions, and modern disturbance. The identification of these concerns helps the technician to develop new techniques, especially when working in conjunction with the field researcher. As seen through the papers in this volume, this symbiotic relationship promises to yield both new breakthroughs in landscape and settlement analysis for Mesoamerican archaeology and enhanced analytic and visualization techniques for lidar with the potential for applicability in other contexts. In many regards, the development of lidar has parallels to the development of radiocarbon dating as a revolutionary technology.

In this article we evaluate ∼48km2 of airborne lidar data collected at a target density of 15 laser shots/m in central Yucatán, Mexico. This area covers parts of the sites of Chichén Itzá and Yaxuná, a kilometer-wide transect between these two sites, and a transect along the first few kilometers of Sacbé 1 from Yaxuná to Cobá. The results of our ground validation and mapping demonstrate that not all sizable archaeological features can be detected in the lidar images due to: (1) the slightly rolling topography interspersed with 1-6 m-high bedrock hummocks, which morphologically mimic house mounds, further complicated by the presence of low foundations; (2) the complex forest structure in central Yucatán, which has particularly dense near-ground understory resulting in a high number of mixed-signal ground and low vegetation returns which reduces the fidelity and accuracy of the bare-earth digital elevation models; and (3) the predominance of low archaeological features difficult to discern from the textural noise of the near-ground vegetation. In this article we explore different visualization techniques to increase the identification of cultural features, but we conclude that, in this portion of the Maya region, lidar should be used as a complement to traditional on-the-ground survey techniques.

Data collected from aerial lidar scanning provides new opportunities for archaeological survey. It is now possible, in a short period of time, to collect vast amounts of geographic data that would have taken years of pedestrian survey to acquire. This enhances and extends landscape studies by reducing time-frames and cost, encouraging analyses based on real-world data collection on a regional scale. This paper describes an approach for modeling the ritual landscape surrounding the ancient Maya center of Las Cuevas, Belize by analyzing the spatial aspects of ritual cave use. Using lidar-derived data, we describe a method for locating potential cave sites using Local Relief Models, which requires only a working knowledge of relief visualization techniques and no specialized skills in computer programming. Our method located the five known cave sites within our 222 km2 lidar study area—including one with a fissure entrance. We plan to ground-truth potentialities to develop models of the ritual landscape that can be visualized and analyzed. By researching cave use on a regional scale and defining the relationships between caves and surface features, we advance cave studies by deepening our understanding of the ritual landscape and its articulation with ancient Maya socio/political dynamics.

Despite the success of lidar in making ancient features visible in certain tropical environments, researchers often have difficulty using lidar to identify small, low, non-linear features. This study juxtaposes lidar data with data gathered from pedestrian survey along the Ucí-Cansahcab causeway, located in the Northern Maya lowlands, to assess the degree to which the invisibility of small buildings in lidar imagery affects demographic research. The juxtaposition shows that demographic research with lidar can move forward in some cases once pedestrian survey has been used as a baseline to establish correction factors for using lidar data on their own. Another current barrier to the use of lidar is cost. This paper provides examples of the kinds of questions that can be addressed by projects with smaller budgets and, therefore, smaller amounts of lidar coverage. These questions include site size comparisons and the degree to which settlement clustered around ancient features such as the Ucí-Cansahcab causeway.

Accurate and high-resolution airborne light detection and ranging (lidar) data have become increasingly important for the discovery and visualization of complete archaeological settlement systems in the Maya Lowlands. We present the results of systematic quantitative analysis of lidar data and ground verification for the major centers of Cahal Pech, Baking Pot, and Lower Dover in the Belize Valley. The Belize Valley is characterized by high density populations living in growing modern towns and villages, and by large-scale agricultural production. This urban environment presents a challenge to reconnaissance efforts since modern construction and agricultural activities have destroyed ancient ruins and created new vegetation patterns. Lidar data was analyzed within a GIS using the Topographic Position Index (TPI) to identify the location of possible archaeological remains. Small-scale, site-level TPI analysis helped identify more detailed archaeological features including small house mounds, terraces, and ditches. Results indicate that lidar data recorded for areas with dense vegetation (e.g., low brush and secondary regrowth) may be less reliable for identification of archaeological remains. The quantitative and qualitative differences between spatial analyses and pedestrian survey results among land cover types indicate that traditional settlement pattern study methods, including pedestrian survey, remain vital to ground-truthing all types of spatial data.

Seasonal wetlands and exuberant crop growth present challenges to systematic archaeological survey in alluvial settings, particularly in the tropical lowlands. Lidar can reduce the time and cost required to survey such areas by allowing targeting of elevated features not buried under recent alluvium, but demographic interpretation requires estimating post-abandonment alluvial depths. The broad alluvial plain between the Papaloapan delta and the Tuxtla Mountains in southern Veracruz, Mexico, offers a valuable case study, featuring seasonally inundated marshes, lakes, and vast fields of sugar cane, a crop infamously obstructive to lidar mapping. Undertaken to reconstruct demographic and organizational change in the Tres Zapotes polity, this study evaluates the benefits and limitations of lidar for archaeological survey in tropical alluvial settings based on overlap between lidar and systematic pedestrian survey and estimates of alluvial depth obtained by auger testing and underscores the importance of timing for lidar mapping in sugar cane.

This study proposes a sampling method for ground-truthing LiDAR-derived data that will allow researchers to verify or predict the accuracy of results over a large area. Our case study is focused on a 24 km2 area centered on the site of Yaxnohcah in the Yucatan Peninsula. This area is characterized by a variety of dense tropical rainforest and wetland vegetation zones with limited road and trail access. Twenty-one 100 x 100 m blocks were selected for study, which included examples of several different vegetation zones. A pedestrian survey of transects through the blocks was conducted, recording two types of errors. Type 1 errors consist of cultural features that are identified in the field, but are not seen in the digital elevation model (DEM) or digital surface model (DSM). Type 2 errors consist of features that appear to be cultural when viewed on the DEM or DSM, but are caused by different vegetative features. Concurrently, we conducted an extensive vegetation survey of each block, identifying major species present and heights of stories. The results demonstrate that the lidar survey data are extremely reliable and a sample can be used to assess data accuracy, fidelity, and confidence over a larger area.

We use the results of a high-resolution lidar survey to assess the advantages and limitations of archaeological applications of lidar data and address some of its methodological challenges. Our data come from the Mopan and Macal River valleys in western Belize, a region that includes several ancient Maya political centers and their hinterlands. Visual inspection of the lidar data has revealed many new sites and new features at previously mapped sites, and these findings significantly enhance our understanding of the valley's cultural history and political dynamics. By comparing data from prior systematic pedestrian surveys, visual and TPI analysis of the lidar data, and analysis of other remotely sensed data, we assess the limits of mound visibility in the lidar data and examine how vegetation and topographic factors impact those limits. We also present slope analysis as a useful tool for predicting whether mounds were constructed in the Preclassic period (1000 B.C.–A.D. 250) or the Classic period (A.D. 250–900).

In April 2009, a lidar survey flown by the National Center for Airborne Laser Mapping recorded 200 square kilometers of terrain that comprised the Classic Period Maya city of Caracol, Belize. The data revealed a highly manipulated landscape of dense settlement, agricultural terraces, and residential reservoirs. Literature on Maya agriculture has discussed the benefits of terraces in controlling soil erosion, retaining water, and managing the gravitational flow of water; however, until now these benefits have not been quantified or demonstrated on the ground at scale. This research utilizes these lidar data and data derivatives in order to test the degree to which the ancient Maya manipulated their environment and were able to support large-scale populations through their landscape management practices. As such, the research provides evidence supporting the significance of agricultural terraces and their impact on limiting soil erosion, increasing water retention, and permitting flow control over rainfall runoff. This research also highlights the conscious effort by the ancient Maya to manage the hydrology of their terraced landscape.

Lidar has been revolutionary to the understanding of ancient Maya anthropogenic landscapes. This is no more apparent than in western Belize, where the scale and resolution of these images have identified vast networks of agricultural terrace systems, revealing their true extent and density. This paper moves beyond the initial identification of terrace distribution to use lidar imagery in combination with digital elevation models (DEM) and hydrological mapping programs (Arc Hydro) to explore the drainage catchments associated with agricultural terraces at the ancient Maya site Waybil, a minor center within the Minanha polity in the North Vaca Plateau. We specifically address how the builders of these relic agricultural features worked with the natural topography to manipulate and create more effective catchments and drainage routes. Results from hydrological modeling describe how terraces created smaller drainage catchments by increasing lower levels of flow accumulation and redirecting routes laterally across the topography. Over a decade of research within this sub-region provides the necessary survey, excavations, and chronological datasets to accurately assess the efficacy of the combined methods for relic terrace drainage analysis.

Lidar has shown considerable utility for answering specific questions regarding anthropogenic landscape alteration in archaeological contexts. We document the extent and timing of these alterations in the construction of the public and political core architectural groups at Uxbenká, Belize, using combined data from Lidar and archaeological excavations. We detail how Lidar methods combined with archaeological excavations enhance the precision of our measurements of the broad range of impacts on the landscape from investment in the built environment. We conclude that the large social investment in landscape alteration to accommodate public architecture occurred early in the polity's history (prior to A.D. 400) and that later developments, including architectural reconfigurations, did not expand greatly on these initial investments.