UAV Surveys Research Articles

Effects of Digital Elevation Model Resolution on Unmanned Aerial Vehicle-Based Topographic Change Detection in Human-Altered Landscapes

UAV-based topographic change detection is widely used in geoscience communities. The change detection involves comparison of two digital elevation models (DEMs) produced by UAV surveys, which are affected by the DEM resolution. Coarse resolution DEMs introduce errors in change detection, but the DEM resolution effect remains poorly understood. Moreover, effective strategies for mitigating the resolution effect have yet to be investigated. This study generated UAV-based DEMs at resolutions ranging from 0.1 m to 10 m with various resampling methods. The impact of DEM resolution on topographic change detection was then evaluated by analyzing the difference of DEM (DoD) and volume budget errors with indices such as mean error (ME), standard deviation (STD), and Moran’s I. The results from two human-altered landscapes showed that the random errors of DoD increase rapidly with the DEM resolution coarsening, while DoD systematic errors (spatial distribution of errors) become stable after 4 m resolution. The volume budget errors also increase with DEM coarsening. Coarser resolution DEMs tend to underestimate the volume budget (gross erosion, gross deposition, and net changes). Moreover, selecting an appropriate method for generating DEM is beneficial in decreasing the errors caused by the resolution effect. Among the seven methods (MAX, MIN, MEAN, BIL, NEAR, NEB, and TIN), the BIL method is optimum for mitigating both DoD and volume errors. The NEAR, NEB, and TIN methods are equivalent, and they are superior to the aggregation methods (MAX, MIN, MEAN). The slope of DoD (SDoD) should be considered when selecting a resolution for change detection. Large errors tend to appear in areas with large SDoD and vice versa. Coarse resolution DEMs are tolerable in areas with low SDoD, while high resolution DEMs are necessary in areas with large SDoD.

Kinetic Analysis of Rainfall-Induced Landslides in May 2022 in Wuping, Fujian, SE China

In the context of global climate change, shallow landslides induced by strong typhoons and the ensuing rainstorms have increased significantly in China’s eastern coastal areas. On 27 May 2022, more than 700 liquefied landslides were induced by the rain gush in Wuping County, Longyan City, Fujian Province, SE China. In light of their widespread occurrence and the severe damage caused, detailed field investigations, UAV surveys, trench observations, in situ tests, and numerical simulation are conducted in this work. The cascading landslides are classified as channelized landslides and hillslope landslides. Long-term rainfall, the influence of vegetation roots under wind load, and differences in the strength and structure of surficial soil are the dominant controlling factors. The sliding surface is localized to be the interface at a depth of 1–1.5 m between the fully weathered granite and the strongly weathered granite. Kinetic analysis of a channelized landslide shows that it is characterized by short runout, rapid velocity, and strong impact energy. The maximum velocity, impact energy, and impact force of the Laifu landslide are 29 m/s, 4221.35 J, and 2110 kPa. Effective excavation is usually impossible in this context. This work highlights the escalating issue of shallow landslides in eastern China’s coastal areas, exacerbated by climate change and extreme weather events like typhoons. By conducting comprehensive investigations and analyses, the research identifies key factors influencing landslide occurrence, such as rainfall patterns and soil characteristics. Understanding the dynamics and impact of these landslides is vital for improving risk assessment, developing effective early warning systems, and informing land management policies in this region. Further exploration concerning hydro-meteorological hazard early warning should be encouraged in this region.

Ice Darkening on Turner Glacier in Auyuittuq National Park, Nunavut

The glaciers of the Canadian Arctic are currently the third largest contributor to global sea level rise due to enhanced Arctic warming driving increased glacier melt and runoff (Zemp et al., 2019). Recent modelling suggests that the glaciers of the southern Qikiqtaaluk region, specifically Baffin and Bylot Islands, are 70% more sensitive to 1°C of warming (Brice et al., 2018). However, these studies lack field-based data to contextualize the drivers of glacier change in this region. Light absorbing particles (LAPs) such as dust, ash, and algae lower the albedo of snow and ice, which is the fraction of light a surface reflects, leading to an increase in the absorption of incoming radiation (Aubry-Wake et al., 2022). On glaciers in western Canada (Engstrom et al., 2022), the European Alps (Di Mauro et al., 2020) and south-western Greenland (Cook et al., 2020), positive feedback mechanisms have been discovered where summer snow and ice melt, augmented by LAPs, leads to the localized release of nutrients in ice and the subsequent enhanced growth of algae. Preliminary remote sensing analysis revealing a dark purple hue on glaciers in the Akshayuk Pass region of Auyuittuq National Park in Baffin Island, NU indicate these processes are likely occurring. The question of how this phenomenon is impacting glacier albedo, and therefore glacier melt which has implications for mass balance and regional sea level rise in the Canadian High Arctic has yet to be answered. Field-based sampling of LAPs on Turner Glacier, characterized through light microscopy and scanning electron microscopy, combined with in-situ hyperspectral spectroradiometer measurements (320nm-1100nm) of the sampled LAPs, and fine resolution (1cm) UAV surveys of sampling sites, are integral to develop a field-calibrated remote sensing approach to monitor LAP accumulation on the glacier surface and to assess the associated melt potential.

Comparison of Carbon Sequestration in Family Forest using Tree Height Measurement by UAV and Field Surveys

Comparison of Carbon Sequestration in Family Forest using Tree Height Measurement by UAV and Field Surveys

A low-cost UAV survey can unravel Baird's Tapir (Tapirus bairdii) trail network dynamics in a neotropical highland forest

UAV technology has transformed spatial data collection and high-spatial resolution analysis of diverse environments around the world. Its role within geosciences, ecology, engineering, and other sciences has been increasing withing the last decade. In ecological and geomorphological aspects, it offers a powerful tool for studying landforms, surface processes, vegetation, and animal behavior globally. Our study employs high-resolution UAV surveys to analyze Tapirus bairdii trail networks and their connection to the landscape in a Costa Rican highland paramo-forest national park. Using a DJI Phantom 4 V.2 UAV, we conducted a photogrammetric flight over 3.19 ha, producing datasets with a spatial resolution of 2.99 cm/pixel. These datasets facilitated geostatistical analysis of Tapirus bairdii trails, revealing their complexity and hotspots near lagoons. We investigated lagoon characteristics, finding that finer sediments spatially correspond with higher trail activity. This suggests that sediment types in lagoons influence Tapirus bairdii navigation, impacting trail network composition. Our findings highlight UAV technology's role in advancing ecological and geomorphological research in protected areas, providing insights into Tapirus bairdii behavior within highland ecosystems. Overall, to the date this is the first high-resolution UAV survey of Tapirus bairdii within these types of highland tropical environments.

Tsunami Modeling Using DEMNAS and DEM Data from UAV Surveys for Planning Evacuation Routes on Samas Coast, Bantul Regency

Tsunami Modeling Using DEMNAS and DEM Data from UAV Surveys for Planning Evacuation Routes on Samas Coast, Bantul Regency

Coastal flood susceptibility assessment along the Northern coast of Portugal

Assessing the susceptibility of sandy beaches to flooding during major storms is an important topic, given the implications that these events can have for beach-dependent coastal systems. A flood susceptibility index based on wave run-up, storm surge and beach morphology is applied to three sectors of the northwest coast of Portugal. An extended ERA5 wave dataset is used (1950–2022) to characterize the most frequent storm events, and topographic data from aerial UAV surveys are examined to obtain specific morphological parameters of the sandy beaches – mean face slope and height of the beach. The flood susceptibility index results show that 54 % of the analyzed coast is classified with extreme or very high susceptibility. The most critical sector is the coastal stretch between Cortegaça and Torrão do Lameiro beaches, where mostly natural systems are present, while the urban front of Furadouro is frequently flooded during storm events. Between Miramar beach (south) and Paramos beach, with a susceptibility index classified between medium and extreme, the presence of some urban fronts points to high-risk exposure situations. The sector between São Jacinto and Poço da Cruz beaches presented lower susceptibility levels for the three urban areas. The problem does not end with the threat to urban fronts, which already have several defense structures, but it is also extends to dune systems and sand dykes.

Terrestrial Laser Scanning (TLS) Survey and Building Information Modeling (BIM) of The Edmund Pettus Bridge: A Case Study

Abstract. The comprehensive digital documentation of the Edmund Pettus Bridge, a symbol of the American Civil Rights Movement located in Selma, Alabama, serves as an example of integrating Terrestrial Laser Scanning (TLS) and Building Information Modeling (BIM) technologies for the conservation of heritage infrastructure. This study aimed to employ advanced TLS and other Reality Capture (RC) techniques to generate a high-resolution, three-dimensional representation of the bridge, thereby aiding in its structural assessment and preservation. Utilizing TLS alongside 360-degree photography and UAV surveys, the project achieved detailed coverage of the bridge's architectural and structural features. The data collected was processed into a BIM model using Autodesk Revit, offering comprehensive analysis and preservation planning. The findings from this research highlighted previously undetected areas of material degradation and structural vulnerabilities, emphasizing the value of TLS and BIM in revealing critical insights into the condition of heritage structures. This project preserved the digital memory of an iconic Civil Rights landmark and set a framework for applying digital documentation technologies in heritage infrastructure conservation. The success of this methodology offers a valuable precedent for future conservation efforts, showcasing how RC technologies can enhance the preservation of historical sites and ensure their legacy is maintained for future generations.

Rift obliquity in the Northern Volcanic Zone in Iceland using UAV-based structural data

Rift obliquity is known to be very frequent at divergent plate boundaries and shear components in the opening of fissures have been detected through seismicity in the monitoring of recent rifting events. However, the field structural evidence of obliquity in active rifts for Holocene events is still poorly studied, despite its relevance at both the lithospheric and upper-crust scales.We performed extensive high resolution UAV surveys on Holocene terrains in four areas along the active rift in the Northern Volcanic Zone of Iceland, to map structures and morphotectonic features in detail. We did a kinematic analysis and found an increase of the obliquity from N to S.We further discuss the origins of this obliquity and suggest that the combination of inherited structures reactivation, magmatic intrusions, and topography influence on the propagation of both fractures and magma intrusions can have an impact on the mismatch between rift opening direction and the far-field strain.We conclude that obliquity can be inferred for Holocene rifting events from surface structural data. It is thus fundamental to take into account the existing structural pattern and its (re)activation history in active rift zones to avoid missing out on possible preferential structure reactivation, magma propagation ways, and eruption sites during the monitoring of ongoing rifting events.

UAV-Based Wetland Monitoring: Multispectral and Lidar Fusion with Random Forest Classification

As sea levels rise and temperatures increase, vegetation communities in tropical and sub-tropical coastal areas will be stressed; some will migrate northward and inland. The transition from coastal marshes and scrub–shrubs to woody mangroves is a fundamental change to coastal community structure and species composition. However, this transition will likely be episodic, complicating monitoring efforts, as mangrove advances are countered by dieback from increasingly impactful storms. Coastal habitat monitoring has traditionally been conducted through satellite and ground-based surveys. Here we investigate the use of UAV-LiDAR (unoccupied aerial vehicle–light detection and ranging) and multispectral photogrammetry to study a Florida coastal wetland. These data have higher resolution than satellite-derived data and are cheaper and faster to collect compared to crewed aircraft or ground surveys. We detected significant canopy change in the period between our survey (2020–2022) and a previous survey (2015), including loss at the scale of individual buttonwood trees (Conocarpus erectus), a woody mangrove associate. The UAV-derived data were collected to investigate the utility of simplified processing and data inputs for habitat classification and were validated with standard metrics and additional ground truth. UAV surveys combined with machine learning can streamline coastal habitat monitoring, facilitating repeat surveys to assess the effects of climate change and other change agents.

Contrasting Changes of Debris-Free Glacier and Debris-Covered Glacier in Southeastern Tibetan Plateau

Debris-free and debris-covered glaciers are both extensively present in the southeastern Tibetan Plateau. High-precision and rigorous comparative observational studies on different types of glaciers help us to accurately understand the overall state of water resource variability and the underlying mechanisms. In this study, we used multi-temporal simultaneous UAV surveys to systematically explore the surface elevation change, surface velocity, and surface mass balance of two representative glaciers. Our findings indicate that the thinning rate in the debris-free Parlung No. 4 glacier UAV survey area was consistently higher than that in the debris-covered 24K glacier in 2020–2021 (−1.16 ± 0.03 cm/d vs. −0.36 ± 0.02 cm/d) and 2021–2022 (−0.69 ± 0.03 cm/d vs. −0.26 ± 0.03 cm/d). Moreover, the surface velocity of the Parlung No. 4 glacier was also consistently higher than that of the 24K glacier across the survey period, suggesting a more dynamic glacial state. The surface mass balance of the Parlung No. 4 glacier (2020–2021: −1.82 ± 0.09 cm/d; 2021–2022: −1.30 ± 0.09 cm/d) likewise outpaced that of the 24K glacier (2020–2021: −0.81 ± 0.07 cm/d; 2021–2022: −0.70 ± 0.07 cm/d) throughout the observation period, which indicates that the debris cover slowed the glacier’s melting. Additionally, we extracted the melt contribution of the ice cliff area in the 24K glacier and found that the melt ratio of this ‘hotspot’ area ranged from 10.4% to 11.6% from 2020 to 2022. This comparative analysis of two representative glaciers provides evidence to support the critical role of debris cover in controlling surface elevation changes, glacier dynamics, and surface mass balance.

Geomorphological assessment as basic complement of InSAR analysis for landslide processes understanding

Landslide research has benefited greatly from advances in remote sensing techniques. However, the recent increase in available data on land surface movement provided by InSAR techniques can lead to identifying only those areas that were active during data acquisition as hazardous, overlooking other potentially unsafe areas or neglecting landslide-specific geological settings in hazard assessments. Here, we present a case study that serves as a reminder for landslide researchers to carefully consider the geology and geomorphology of study areas where complex active movements are detected using InSAR technology. In an area extensively studied using InSAR and UAV-related techniques, we provide new insights by applying classical approaches. The area is the coastal stretch of La Herradura, and its importance lies in the fact that it has served as an illustrative example in the Product User Manual of the European Ground Motion Service, a platform that provides ground motion data on a European scale. Our approach is to revisit the area and carry out qualitative geological and geomorphological assessments supported by UAV surveys and GIS spatial analysis on a broader scale than previously published investigations. Our classical approach has yielded the following new observations, crucial for risk assessment and land management: active landslides identified by InSAR techniques since 2015 are bodies nested within large mass movements that affect entire slopes. A variety of processes contribute to slope dynamics, such as large slumps, marble rock spreading and block sliding, and surface rock falls and topples. The revised delineation of the landslide bodies reveals an area almost five times larger than previously mapped. These new findings in a well-known area highlight (1) the importance of updating and downscaling previous maps and (2) the ongoing importance of classical fieldwork and desk studies as basic complements to modern InSAR analyses.

Yearly Elevation Change and Surface Velocity Revealed from Two UAV Surveys at Baishui River Glacier No. 1, Yulong Snow Mountain

Glaciers play an important role in understanding the climate, water resources, and surrounding natural change. Baishui River Glacier No. 1, a temperate glacier in the monsoon-influenced Southeastern Qinghai–Tibet Plateau, has experienced significant ablation due to regional warming during the past few decades. However, little is known about the yearly changes in Baishui River Glacier No. 1. To investigate how Baishui River Glacier No. 1 has changed in recent years, digital orthophoto maps and digital elevation models were obtained from an unmanned aerial vehicle on 20 October 2018 and 22 July 2021, covering 84% and 47% of the total area, respectively. The results of the Baishui River Glacier No. 1 changes were obtained by differencing the digital elevation models, manual tracking, and terminus-retreat calculation methods. Our results showed that the surveyed area had a mean elevation change of −4.26 m during 2018 and 2021, and the lower area lost more ice than other areas. The terminus of Baishui River Glacier No. 1 has retreated by 16.35 m/a on average, exhibiting spatial variation with latitude. Moreover, we initially found that there was a high correlation between surface velocity and elevation gradient in this high-speed glacier. The surface velocity of Baishui River Glacier No. 1 was derived with the manual feature tracking method and ranged from 10.48 to 32.00 m/a, which is slightly smaller than the seasonal average. However, the snow coverage and ice melting of the two epochs led to the underestimation of our elevation change and velocity results, which need further investigation.

Proglacial lake evolution coincident with glacier dynamics in the frontal zone of Kvíárjökull, South‐East Iceland

AbstractThe termini of Icelandic glaciers are highly dynamic environments. Pronounced changes in frontal ablation in recent years have consequently changed ice dynamics. In this study, we reveal the inter‐seasonal dynamics of the Kvíárjökull ablation zone and proglacial zone using ArcticDEM and Sentinel‐2 images acquired between 2011 and 2021 and intra‐seasonal dynamics with repeated UAV surveys during summer 2021. Average glacier surface velocity in the ablation zone ranged from 51 m year−1 in 2015 up to 199 m year−1 in 2018, with maxima within the axial zone of the glacier and minima on the glacier edges. Coincidentally, and in accordance with glacier retreat/advance, the ice‐marginal proglacial lake fluctuated in its area, and we interpret that it was also a key factor in the development of the glacier terminus morphology. A complex spatial pattern of glacier surface elevation changes, including thickening in the frontal true left margin of the terminus, is interpreted to be due to variable subglacial topography, relatively fast ice flow from the accumulation zone and an insulating effect of glacier surface debris cover. In contrast, the true right (southern) part of the glacier terminus experienced thinning and retreat/disintegration also during the 2021 summer season, which we attribute to enhanced frontal ablation connected to the intrusion of lake water into the crevassed glacier terminus. Overall, this study suggests that where glaciers are developing ice‐marginal lakes complex patterns of glacier dynamics and mass loss can be expected, which will confound understanding of the short‐term evolution of these environments.

Is It More Visible from Above? Comparison of the Effectiveness of Methods for Locating the Bobak Marmot Marmota bobak (Rodentia, Sciuridae) Burrows in Ukraine

Burrow systems detection is a reliable method for counting Bobak marmots. We compared the effectiveness and labour costs of three methods of burrow detection: ground survey, unmanned aerial vehicle survey and satellite survey. The research was conducted in 2021 (Kyiv region). Ground surveys mapped 42 (12 main and 24 secondary) burrows, while UAV imagery identified 45 burrows. The proportion of burrows detected by satellite imagery was 48 % of the number of burrows mapped by the ground survey. Secondary burrows were more difficult to detect than main burrows. The largest area of marmot family group territories was calculated from UAV data (0.27 and 0.08 ha), the smallest from satellite imagery data (0.11 and 0.01 ha). To obtain complete information on marmot colonies, it is best to use either UAV surveys or traditional ground surveys. If it is necessary to find potential areas where animals may live, or to estimate their distribution, then the best option for detecting burrows is the analysis of satellite imagery. The most promising approach is to study colonial burrowing mammals using a combination of ground and remote sensing methods. This provides the opportunity to obtain different types of data.

Infrared thermography monitoring of solar photovoltaic systems: A comparison between UAV and aircraft remote sensing platforms

The continuous increase in the number and scale of solar photovoltaic power plants requires the implementation of reliable diagnostic tools for fault detection. With the recent advances in low-weight, high-precision, and fast-response thermal cameras, along with professional aerial platforms, aerial infrared thermography (aIRT) is currently the most popular method for non-destructive, fast, and relatively inexpensive monitoring of photovoltaic (PV) power plants. Typically, aerial inspections are conducted using a UAV (drone) equipped with a thermal camera to produce a report indicating detected thermal defects, typically associated with failures. The main purpose of this paper was to compare the thermographic results for two different PV plants provided by two remote sensing-based approaches: the classical UAV-mounted thermal camera survey and the inspection by high-speed thermal cameras mounted on an airplane. The post-processing of thermal patterns showed good agreement between the results provided by the two aerial platforms, with an overlap of thermal anomalies detected up to 98%. An economic analysis demonstrated that, while airplane surveys incur higher costs (compared to UAV surveys) due to the hire of vehicles and more expensive instrumentation, they, on the other hand, require a reduced amount of time and may be more convenient when inspecting large-scale PV plants or multiple PV plants located within a close area.

GEODETIC PLANNING IN THE AGRICULTURAL LANDSCAPE: CREATION OF DIGITAL MAPS AND MODELS FOR LAND USE OPTIMIZATION

The article is devoted to the topical issue of geodetic planning in agro-landscape and its importance for efficient land use. The authors review modern methods and technologies for creating digital maps and models of agricultural landscapes based on the use of geographic information systems and aerial photography from unmanned aerial vehicles. Modern new approaches to geodetic planning within agrolandscapes are investigated. The requirements of the agricultural sector for digital mapping and modeling for the optimal use of land resources are determined. The tools for the formation of digital maps of agro-territories of united territorial communities are substantiated. Proposals for the use of geodetic methods for effective agro-landscape planning are formulated. The main attention is paid to the practical significance of the data obtained for optimizing land use, planning agricultural operations and rational use of land resources. The studied approaches and developments can be useful for farmers, landowners, ecologists and specialists in the field of geodesy. In the course of the study, a methodology and procedure for mapping agricultural landscapes using GIS and aerial survey materials using UAVs were developed. This methodology made it possible to obtain high-quality images of agricultural landscapes and develop a cartographic model in GIS based on them. The approach was successfully tested on the example of the selected model area near the ATC. The created digital map and database are promising for further research of agricultural landscapes. The research clearly shows that the data obtained as a result of UAV surveys is a high-quality source of reliable information. Aerial photography allows you to quickly create an accurate digital terrain model, which can serve as the basis for geographic information systems in the development of a number of thematic maps and terrain models important for the agricultural sector. The geographic information system makes it possible to visualize the main elements of agricultural landscapes as separate layers (e.g., relief, soil-forming rocks) with appropriate detailing of their characteristics in attribute tables. By combining different data sources, GIS allows you to create detailed maps of the agro-ecological conditions of a particular area. GIS can also be used to store information on field work, yields and other indicators, which ensures the rational management of agricultural processes on land plots.

ASSESSING THE ACCURACY OF UAV SURVEYS WITH DIFFERENT CONFIGURATIONS

Abstract. Recently, developments in airborne sensors and easy-to-fly, reliable, low-cost commercial UAVs have opened a new era for precise aerial mapping. The restricted payload capacity of low-cost UAVs imposes constraints on the quality of their navigation systems and the sensors they can carry. Therefore, the quality of photogrammetric products generated from UAV surveys needs to be assessed. In this study, photogrammetric mapping principles are employed in collecting, processing, and analyzing optical images collected using two UAV surveying systems. The first system was a 3DR Iris+ drone flying at 25 meters above the ground. The second system was a homemade drone similar to Tuffwing flying at about 70 meters above the ground. Both systems carried a Canon PowerShot S100 using a fixed 5.2 focal length. About 30 ground points were surveyed with a TS02 total station and served as the ground truth for data evaluation. After the flights, data was proceeded and geospatial products including DEMs and orthophotos produced were evaluated. Different ground control configurations were examined and ground check-points were used to evaluate the final accuracy of the geospatial products. The comparison of the derived 3D information from captured data with ground measurements showed a high correlation between the accuracy of the 3D products and the sensor specification, flying altitude, as well as image layout. This was supported by comparisons between actual errors and theoretical positional precision based on flying height, photo scale and air base was conducted.

Response of a small, forested stream to a large input of sediment

In small headwater channels coupled to hillslopes, episodic supplies of sediment from events like landslides can dominate local channel morphodynamics and impact ecosystem health. In this study we investigate the response of a small mountain stream in British Columbia to a sediment input event that was up to 150 times the volume of sediment transported in an average flood year caused by the upstream installation of a road bridge. Using four years of repeated UAV surveys, bedload tracers, and other field monitoring techniques, we examined the spatial and temporal changes in sediment storage along the reach, identified changes to channel morphology, and characterized the interaction between the channel bed and the supplied sediment. Historical monitoring of the reach allowed for a comparison of the response to nearly 20 years of information about bedload transport and morphologic change. We observed that most of the change within the reach occurred during the first flood after bridge installation. The supplied sediment mostly moved across the bed surface with little interaction, as tracers installed in the bed had lower than expected rates of mobility. A narrow, steep segment of the channel proximal to the bridge installation stored little sediment, whereas a wider, less steep segment further downstream absorbed much of the change. This effect was exacerbated by a logjam that formed during the first flood after bridge installation. Despite the relative magnitude of the sediment transport event, there was little change to the channel pattern, with the added sediment increasing the relief of the already existing morphologic units. This suggests river managers should focus their restoration attention on segments likely to respond to a disturbance and that the pool-riffle channel morphology can persist across a wide range of sediment-supply conditions.

Thermal signatures of relict coal spoil, waste and tailing dumps

ABSTRACT As relict features of coal mines, carbonaceous spoil, waste and tailing dumps remain susceptible to coal oxidation and thermal decomposition, together with spontaneous combustion. Modern methods for monitoring surface thermal signatures regularly include the use of UAV’s, equipped with suitably sensitive infrared cameras. Detection of sub-surface thermal anomalism includes Vegetation Index Monitoring and/or the use of in-ground probes. Research across thermally active tailings offers insights into how best apply these two techniques, and increasingly the required scheduling of UAV surveys.