Previously mapped square-kilometer area of Caracol settlement and terraces superimposed on a 2D hillshade of the LiDAR DEM, showing congruence. Causeways are visible to either side; residential groups were mapped throughout the square kilometer, but before the LiDAR survey agricultural terracing was recorded systematically only between the two causeways. 

Context in source publication

Context 1

... of indigenous calendar systems and the appropriate positioning of diverse styles and cultural developments across a broad geographic area, allowing a better understanding of that cross-cultural interactions. Currently, technological advances are leading to a geospatial revolution and a second period of rapid change in archaeology, one focused on outlining large-scale natural and human-built landscapes. The effects of this technology are being felt most clearly in forest-covered areas of Mesoamerica where ancient landscapes traditionally have been most dif fi cult to de fi ne. Just as radiocarbon dating transformed the temporal domain, the current geospatial innovations are bringing a semblance of con- trol to the spatial domain and are helping signi fi cantly with the interpretation of past sociopolitical complexity. Settlement and landscape archaeology have formed key build- ing blocks for the study and reconstruction of ancient human occupation and interaction with the environment (23, 24). These approaches have altered the way archaeologists view ancient civilizations by focusing on both small and large sites, by showcasing urbanism, and by pointing to fallacies in views of settlement density and agricultural practices (25 – 28). However, the impact of settlement and/or landscape archaeology has been limited in areas that are heavily forested, where on-the-ground survey and the use of traditional remote sensing techniques can be dif fi cult and un- reliable. Past mapping efforts, especially in the Maya area, generally covered only a limited sample of any single site and rarely contextualized settlement in terms of its overall landscape (28), so that nonarchaeological data often took precedence in establishing sociopolitical models. Our spatial knowledge of parts of Mesoamerica that were less heavily vegetated, such as the Valley of Mexico (29) and the Valley of Oaxaca (30 – 32), is much greater than that of the generally jungle-covered Maya region. To some degree, this difference in knowledge has led to a long-standing imbalance in our understanding of scale and complexity in the Maya area compared with many parts of the Mexican highlands. Ethnohistory, iconography, and ancient documents have all been used to try to explain the ancient sociopolitical and economic organizations once extant in Mesoamerica, but these data sets are limited in what they can accomplish. The late 15th and 16th century European accounts described peoples whose activities and sociopolitical institutions had been changed greatly by contact and disease. The breakthroughs in epigraphy that occurred in the 1990s signi fi cantly advanced interpretations about the ancient Maya, but texts dealt only with a small segment of ancient Maya populations. There was a disconnection between much of the epigraphy, which focused on events in the lives of “ kings and queens, ” and the archaeology, which reconstructed past day-to-day ways of life (33). Models based on epigraphy focused on dynasties and hegemonic empires (34), but what these units actually looked like on the ground only could be conjectured. Because the spatial parameter was not fully controlled, a multitude of sociopolitical models pro- liferated. Long-standing questions about Maya urbanism (35, 36), their ancient population sizes (37), and the structure of their states (38) remained unanswered, with some researchers insisting that the Maya were not especially developed (39, 40) and others ar- guing for a range of complex systems (41). Similar issues, largely driven by ethnohistory and not epigraphy, existed in the highlands of Mesoamerica, especially in regard to the extent and role of Tula in central Mexican developments (42). The lack of concrete spatial parameters and the limited samples gained from archaeological sites made it extremely dif fi cult to know which sociopolitical models were appropriate. However, this imbalance is being rem- edied, in part by the application of LiDAR technology that can penetrate forest and scrub canopies to record landscapes and archaeological ruins accurately at high spatial resolution. The more complete LiDAR data demonstrate that some ancient Mesoamerican sites are far more extensive and complex than was thought possible following popular sociopolitical models (43). The initial test of LiDAR in the Maya area was undertaken by the National Center for Airborne Laser Mapping at Caracol, Belize in April 2009 and yielded spectacular results (28, 43 – 45). The LiDAR data from Caracol provide a view of an integrated Maya urban center that covers ∼ 200 km 2 (Fig. 2). Importantly, these data can be ground-truthed through comparison with 23 km 2 of transit-mapped settlement (46, 47) and more detailed mapped areas of ancient agricultural fi elds (48). Superimposing previously surveyed areas of housing, administrative and ritual constructions, agricultural terracing, and causeways on LiDAR digital images showcases the accuracy of the methodology (Fig. 3). The decades of collected archaeological data from Caracol provide both temporal and functional contexts for the newer LiDAR data, permitting both an understanding of how the anthropogenic landscape evolved and a dating of A.D. 700 for the occupational peak of the archaeological remains (28, 43). LiDAR not only is successful in “ seeing ” the larger architecture and roadways in the site epicenter (Fig. 4) but also accurately portrays very low constructions, outlying architectural nodes, and the magnitude of agricultural terracing throughout Caracol (Fig. 5). Even small openings into the ground that represent un- derground storage units (called “ chultuns ” ) and looted burial chambers in structures are visible; a large number of caves similarly have been detected and ground-checked (49). This single Digital Elevation Model (DEM) laid the groundwork for a transformational shift in Maya archaeology by providing for one Maya site a complete landscape rather than merely a sample of the settlement that could not be fully contextualized. Although previously it had been possible to dismiss the size estimates for Caracol as being based on selective sampling (e.g., ref. 50, pp. 234 – 236), the LiDAR results con fi rmed and visually demonstrated Caracol ’ s scale (28). The LiDAR provides a full view of the 200- km 2 area of Caracol, depicting a sprawling Maya city replete with markets, roads, and almost continuous agricultural terracing, thus corroborating the archaeological data that indicated a massive population focused on sustainability and site-wide integration. These data securely place Caracol, presumably along with some other ancient Maya cities, into a tropically de fi ned phenomenon known as “ low-density urbanism ” (51, 52). A further application of LiDAR was made in 2011 over the site of Angamuco located within the Lake Pátzcuaro Basin in west- central Mexico (53). The results here were as successful as the Belize application. An area of 9 km was over fl own, uncovering an exceedingly dense urban occupation in this prehispanic Purépecha (Tarascan) region. The form and layout of Angamuco revealed by the LiDAR data show a site that has hundreds of residential groups bounded by walls and streets that articulate with larger, distinctively Purépecha, monumental architecture (Fig. 6). Like Caracol, previous survey data from Angamuco shows a high congruence with the LiDAR data as well as a largely human-constructed environment. However, the scale and organization of this settlement was not expected and is contrary to current models of complex social development in the region (e.g. ref. 54). The Angamuco residential settlement closely resembles residential patterning seen at the site of Cantona, Puebla in east- central Mexico (55), considered to be anomalous for that region. From a research perspective, LiDAR has changed the way in which archaeologists view ancient Mesoamerica. With LiDAR coverage of the Mesoamerican landscape, interpretations of spatial organization no longer need to be based on a small survey sample of an unde fi ned larger universe or require extensive on-the ground penetration of forest canopy. LiDAR can remove pre- conceptions about ancient size, scale, and complexity effectively by providing a complete view of the topography and ancient modi fi cations to the environment. The power of this technology also can be seen in its rapid application in other tropical regions: LiDAR surveys have been completed recently around Uxbenka in southern Belize, around Izapa in southern Mexico, along the Mosquito Coast of Nicaragua, and over Angkor Wat in Cambodia. LiDAR effectively allows the archaeologist to understand the ancient use of space, serving as a counterbalance to interpretations derived solely from small survey samples or nonarchaeological sources. For Caracol, LiDAR clearly reveals the massive population and areal extent of the settlement, con fi rming its position as one of the major sites of the Late Classic Maya world and visually demonstrating a broad-scale integrative sociopolitical organization only hinted at in models generated from the Maya hieroglyphic record and ethnohistory. Angamuco reveals an urban development in an area of central Mexico where none was expected, revealing part of the vast population that occupied the Tarascan region before empire formation in a context that was completely unexpected in current models. The spatial distributions of settlement and other constructed features can be conjoined with archaeological and epigraphic materials to answer questions about the organization of Maya polities (see ref. 56 for an example from western Guatemala); LiDAR facilitates this task. LiDAR also provides a spatial canvas on which archaeological insights into the physical population structure of ancient Mesoamerican societies can be better displayed. Stable isotope analysis provides information about diet and status; strontium analysis and oxygen levels provide ...