Many Classic Maya cities display aspects of wealth inequality, including monumental architecture, prestige goods economies, and differences in residential units. I evaluate wealth inequality at two Late Classic (AD 600–810) cities in northwestern Belize: Chan Chich and Ayiin Winik. Using legacy data and lidar data in GIS, I measured the area and volume of residential groups and calculated a Gini coefficient for each site. I found that both Chan Chich and Ayiin Winik had high Gini scores, reflecting extreme residential disparities. These findings largely parallel those of previous studies at other sites, alluding to regional trends in inequality in which sites in the well-connected and centralized Maya heartland of the broader Petén tend to have higher Gini coefficients than sites located in other subregions of the Maya world. My findings highlight variability in residential wealth inequality across the Maya Lowlands.

Plant invasions are one of the most important drivers of global biodiversity change, posing a major threat to ecosystem health and human well-being. Invasion pressure is not uniformly distributed across biomes and ecosystems. Although tropical forests are often considered resistant towards alien plant invasions, the drivers behind this resistance as well as the actual impact require further clarification in tropical contexts, where dynamics often differ from those in temperate regions. This study investigated the role of tree diversity and vegetation structure in influencing plant invasions across four major land cover types in Sumatra, Indonesia: natural forests, fallow land, rubber, and oil palm plantations. We derived vegetation structure metrics such as canopy height, number of gaps, box dimension, skewness from landscape-scale mobile LiDAR measurements collected across 100 plots and analysed these metrics alongside species diversity data, focusing on both native trees and invasive alien plants. Our results reveal that more diverse tree communities were associated with taller (higher canopy height), more structurally complex (higher box dimension), less open (smaller gap area) vegetation. In contrast, a simplified vegetation structure was more prevalent in monoculture plantations, which correlated with a higher abundance and diversity of alien plants. These results underline the critical role of tree diversity and vegetation structure in shaping the invasibility of tropical ecosystems. Our findings support restoration that maintains multi-layered canopies and limit gap area. These practices should be prioritised to enhance ecosystem resilience and mitigate the impact of biological invasions.

Total water levels (TWL) – the combination of wave-runup, tides, surges and in the future, sea-level rise – stand as a critical variable contributing to coastal inundation during storms. Quantifying the contribution of wave runup to extreme TWL is essential for accurate assessments of coastal inundation risk at wave-dominated coastlines. Despite decades of research, a fundamental challenge for coastal practitioners is selecting from numerous runup models, often constrained by the unavailable site-specific beach slope data. This study presents a novel dataset of TWL observations inferred from marine debris deposits surveyed immediately after storms in New South Wales, Australia. Using this dataset, this work assesses the accuracy of simplified TWL models integrating still water levels, local nearshore wave data, various runup formulae and different beach slope proxies derived from remote sensing technologies. Models utilising historical beach slopes from LiDAR outperformed the models using satellite-derived slopes. Findings suggest that runup formulae calibrated during small-to-moderate wave conditions can be extrapolated to extreme storms when applied to similar sites, emphasising the preference for site-specific formulae over one-model-fits-all approaches. Challenges and opportunities of modelling TWL for coastal inundation assessments are discussed, highlighting the need to incorporate beach slope uncertainties to fully assess inundation impacts as sea-levels rise.

Throughout the precolonial era, monumentality in the midcontinent was expressed through a variety of earthen constructions from circular mounds to animal effigies to geometric shapes to depictions of spiritual beings. Here, we describe an example of megalithic monumentality located at the Menominee Reservation in Wisconsin, USA. This archaeological feature uses a mix of the natural geology alongside anthropogenic efforts to depict the Menominee legend of a battle between the Thunderbird and Serpent. The encountering and documentation of this megalith were the result of ongoing collaborative efforts that brought together archaeological techniques with Menominee knowledge sets. We describe the megalith and draw on the only other known megalithic effigy from Wisconsin, a serpent effigy, located in ancestral Menominee territory and documented more than a century ago. Together, these two megalithic features illustrate currently unrecognized monumental construction efforts in the midcontinent and highlight the value and importance of collaborative approaches to documenting and preserving archaeological heritage.

This study reports on 26 Maya ballcourts in the southeastern Three Rivers adaptive region, many of which are newly identified through a 2022 lidar survey. We analyze the ballcourts in terms of their form, dimensions, orientations, and integration with processional and ceremonial architecture. Statistical analyses and comparisons with ballcourts from neighboring regions, including the Belize River Valley, Holmul, and the western and northeastern Three Rivers region, highlight both shared architectural norms and regional variations, particularly in alley width and the relationship between alley length and width.

This paper addresses the challenge of robotic path planning in high-temperature operational environments. Aiming at the limitation of traditional methods that rely on geometric information while ignoring thermal radiation data, a potential field method path planning based on temperature-enhanced point cloud maps is proposed. By fusing the data of LiDAR and thermal imager, point cloud maps with temperature attributes are generated. Based on the traditional potential field method, the potential field function of thermal radiation repulsion was introduced. The temperature gradient of the heat source is transformed into the potential energy constraint of path planning to achieve path generation in high-temperature areas. The experimental results show that, compared with the traditional artificial potential field method, this study provides a new technical solution for the safe operation of robots in a thermal environment.

Archaeologists have demonstrated the value of deep learning models for detecting archaeological objects in lidar data. As landscape-level projects become the norm, archaeological data derived from deep learning predictions can be integrated into these initiatives through coupled natural-cultural landscapes planning. However, the paucity of archaeological training datasets limits the application of deep learning models to relatively common and well-documented object classes. Using procedurally generated training datasets may be one approach to overcome this bottleneck. To test the efficacy of procedural generation for developing deep learning training data, we trained models to detect a novel object class (hypothesized historic tar kilns) in the Kisatchie National Forest in Louisiana. We developed two procedural generation approaches to embed simulated archaeological objects in a lidar-derived DEM and used these datasets to train deep learning (Mask R-CNN) models. We then evaluated model predictions within lidar-derived visualizations and during field survey. Our trained models detected targets with high recall but low precision. Field investigation suggested that the objects were not tar kilns but a different historic feature class. This study suggests that models trained on simulated objects are a useful addition to lidar analysis tool kits and can be directly integrated into archaeological field investigation workflows.

A previous assessment of the measurement unit employed in building the Antonine Wall compared the distance slabs with LiDAR-derived three-dimensional distances on the ground and concluded that it was the pes Drusianus. Using more precisely determined discovery locations, correcting an error in previous published calculations and making allowance for installations already built, establishes that the unit was the pes Monetalis. The wider implications are examined, concluding that postulated secondary forts were, indeed, later additions; that fortlets were an integral part of the original plan, though not all were constructed before the rampart; that there is no direct correlation between the location of the slabs and pre-existing installations; and that the Bridgeness–Avon sector was one of the earliest to be constructed.

Concordia Station is a long-term lidar observatory in Antarctica. Its main purpose is to detect and classify polar stratospheric clouds (PSCs). In September 2023, water ice PSCs were observed for a period of 6 days. This has never occurred during the month of September in the 10 years of observations of PSCs at Concordia Station. In addition, the space-borne CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) lidar observed a rare occurrence of ice PSCs over Concordia Station during the first half of June. It is well known that the January 2022 eruption of the Hunga submarine volcano (20°32’S, 175°23’W) injected vast amounts of water vapour into the stratosphere. The Hunga hydration flooded southern high latitudes at the end of the 2022 austral winter, and the moist air was then entrained into the developing vortex in the austral autumn (April–May) of 2023. The increased water vapour from Hunga was reported to promote PSC formation by cooling the stratosphere and raising PSC formation temperatures. Here, we explore the impact of the Hunga eruption on the PSCs observed at Concordia Station.

This paper proposes an indoor LiDAR-visual fusion framework based on dynamic elimination. The framework effectively suppresses transient dynamic interferences. It integrates multi-view geometric constraints with semantic priors, which is achieved through a prior model-guided dynamic feature elimination strategy. Moreover, an adaptive gamma correction (AGC) algorithm enhances the image quality under uneven illumination. Meanwhile, an improved quadtree algorithm homogenizes feature point distribution. These two measures achieve more robust ORB feature extraction while ensuring image quality. For map fusion, we focus on combining the processed visual map with the LiDAR map. The visual map, with dynamic feature points eliminated, is first aligned with the LiDAR map via Harris corner detection. We then integrate them using Bayesian inference-based grid information fusion to generate the final integrated map. Extensive evaluations were carried out on six dynamic sequence datasets, and practical dynamic corridor mapping experiments were also conducted. These evaluations and experiments demonstrate the superiority of the proposed system.

Las antiguas élites mayas jugaban a la pelota. Esta acción y las actividades asociadas se enfatizan para complementar las interpretaciones simbólicas de estudios anteriores. Basándose en la teoría de conjuntos, se discute cómo las interacciones recurrentes y causales institucionalizaron el juego de pelota. Los análisis multiescalares y multidimensionales permiten estudiar las relaciones parasociales, asimétricas y co-constitutivas entre los jugadores, el público y la cancha. En el este de las tierras bajas mayas, se encuentra el centro de Tzikin Tzakan, donde se documentaron dos canchas de juego de pelota. Debajo de la parte de las superficies originales de la cancha oeste, se encontraron varias capas de lascas de pedernal. Su presencia infiere la furia y el dolor que ocurría durante el juego de pelota. Los nobles jugaban sabiendo que sufrirían y hasta podrían fallecer. Se documentó un basurero que probablemente refleja las fiestas asociadas al juego y que apunta al rol del público en crear y gozar un espectáculo. Comparadas con 50 canchas cercanas, las canchas de juego de pelota de Tzikin Tzakan destacan por su orientación, su forma y sus dimensiones. Sus características regionalmente únicas y localmente compartidas ejemplifican el juego de pelota como una totalidad emergente.

One of the most significant engineering accomplishments of Maya civilization is Sacbe 1, a raised road connecting the ancient urban centers of Yaxuna and Coba. Using new lidar data in concert with excavation, epigraphic inscriptions, and landscape reconnaissance, we show that settlement and an urban experience emanated westward from Coba along the sacbe. The leaders of Coba—in particular, an ambitious seventh-century queen—used the sacbe to expand the political and cultural influence of their dynasty into the center of the peninsula while securing territory and resources. Gaps in the sacbe, precise delineation of its many curves, and examination of features near these curves call to mind several possible intentions governing its construction and use. Sites located along the causeway did not present significant barriers to the expansion of Coba. Sacbe 1 represents a uniquely urban space that expanded urban social networks into a rural hinterland while advancing state interests for territory and influence.

Aerial lidar (light detection and ranging) has been hailed as a revolutionary technology in archaeological survey because it can map vast areas with high-precision and seemingly peer beneath forest cover. This excitement has led to a proliferation of lidar scans, including calls to map the entire land surface of earth. Highlighting how the growth of aerial lidar is tied to fast capitalism, this article seeks to temporarily pause the global rush for data collection/extraction by focusing on the ethical dilemmas of remotely scanning Indigenous homelands and heritage. Although lidar specialists must obtain federal permissions for their work, few engage with people directly in the path of their scans or descendant stakeholders. This oversight perpetuates colonial oppression by objectifying Indigenous descendants. To address Indigenous objectification, I argue that aerial lidar mapping should be preceded by a concerted, culturally sensitive effort to obtain informed consent from local and descendant groups. With the Mensabak Archaeological Project as a case study, I demonstrate how aerial lidar can become part of a collaborative, humanizing praxis.

Following the identification of more than 600 suspected house platforms on aerial survey data from Brusselstown Ring hillfort, four test excavations revealed evidence of Late Bronze Age and Early Iron Age occupation, positioning the site as the largest nucleated settlement so far identified in prehistoric Ireland and Britain.

The June 2016 extratropical cyclone with anomalous ENE storm wave direction caused widespread beach-foredune erosion in southeastern Australia. At Bengello Beach, erosion volumes were 97–108 m3/m for the central and southern parts of the beach, while the northern end only lost 18 m3/m of sand. In the central and southern parts of the embayment, a surf zone bar formed 50–100 m further seaward than is typical for this beach and was a temporary store of sand eroded from the beach-foredune. A nearshore wave model showed substantial variability in wave power along the 10 m depth contour and explained the partial sheltering of the northern end of the embayment from storm impact. An embayment-wide time-series of airborne LiDAR further emphasised the alongshore variability in beach-foredune erosion. The wide beach and broad, double-crested, well-vegetated foredune along much of the embayment was pivotal in protecting the shoreline. In the centre and south of the beach, recovery took nearly three years and although complete by volume, the foredune was narrower and less resilient. The results emphasise the role of wide beaches and natural vegetated foredunes in buffering extreme storms and suggest foredune rehabilitation should be a key management priority for sustainable coasts.

Mountains figure prominently in Mesoamerican cosmogeny, and a deep history of pilgrimage and worship surrounds many, though few have been systematically investigated using modern archaeological methods. Here, the authors present results from the lidar mapping and surface survey of a plateau at the summit of Cerro Patlachique, located at the southern limit of the Teotihuacan Valley, Mexico. While ceramic typology establishes Cerro Patlachique as a site of pilgrimage before, during and after the occupation of Teotihuacan, the documentation of 34 carved monuments substantially expands the existing corpus and identifies the summit as a place of convocation with water deities.

Quarries are information-rich anthropic landscapes, but their unique characteristics often limit the effectiveness of traditional archaeological documentation strategies. Here, the authors present a novel interdisciplinary method for the documentation and analysis of these landscapes, focusing on two ancient marble quarries on the Mediterranean island of Naxos. The workflow, combining lidar, photogrammetry, sculptural and architectural study, geoscience, ecological study and archaeological survey, provides a means for the systematic documentation of quarry landscapes in the Mediterranean and beyond, and aims to promote an understanding of premodern extractive activities not as isolated occurrences but as important aspects of interconnected, evolving landscapes.

A 103 km2 aerial lidar survey of Dzibanche/Kaanu’l, Mexico, reveals the city’s settlement to be more populous and well-organized than previously thought. The sprawling settlement incorporated the early center of Ichkabal in a network of smaller peri-urban civic-ceremonial nodes. The density and complexity of the Kaanu’l settlement is consistent with its extraordinary political reach as a multiregional hegemonic state. The city and settlement grew to their maximum extent during the Early Classic period until AD 630. The lidar-derived data show that Dzibanche may have had the largest monumental zone and highest population density in the Maya Lowlands at that time. The Early Classic layout was unaltered by later construction, allowing us to document a well-developed system of causeways connecting an urban center and peripheral plaza groups with surrounding settlements and agricultural fields. The spatial organization and interconnectedness of this Early Classic settlement suggests a greater level of urban planning for optimal flow of goods and people across urban and peri-urban zones than previously thought.

Simultaneous localization and mapping technology is the basis for multi-robot systems to complete navigation, path planning, and autonomous exploration in complex, dynamic, and Global Positioning System (GPS)-denied environments. This paper reviews the current status and progress of multi-robot simultaneous localization and mapping (SLAM) technology based on LiDAR. First, this paper studies the basic principles of LiDAR SLAM. It analyzes the system model construction of LiDAR SLAM, including the mobile robot coordinate system model, kinematic model, sensor model, map presentation, LiDAR SLAM framework, and classic algorithms. Then, this paper discusses the basic framework of collaborative SLAM, analyzes the key issues such as data association, loop closure detection, and global graph optimization in collaborative SLAM, and conducts a detailed literature review on the solutions to key problems in sub-fields of multi-robot SLAM such as frontier detection, task allocation, map fusion, and compares the advantages and disadvantages of various algorithms. Finally, this paper outlines the challenges and future research directions of multi-robot LiDAR SLAM.