Elevation Map Research Articles

ESTUDO GEOMORFOLÓGICO E DESCRIÇÃO DE SEDIMENTOS DO BAIXO CURSO DA MICROBACIA DO CÓRREGO DO BRUMADO, SANTA RITA DURÃO/MARIANA MG

The Quadrilatero Ferrifero is an important metallogenic region constituted by pre-Cambrian lithology that has a great collection of bibliographic materials. The Córrego do Brumado basin is localized on the east edge of the quadrilátero and next to the district of Santa Rita Durão and inserted in the reverse flank named Santa Rita synclinal. This approach focuses on the regional geomorphology with post analysis of the sediments collected on the low stream of the river. With bibliographic research and topographical chart analysis, it was possible recognize the study field and recognize the strategic visitation points. The collected samples were examined through a binocular loupe to obtain details about the aspects of their grains and mineralogy. The local geomorphology was analyzed following the classification of the IBGE geomorphological guide. In the scenario, the geological and geomorphological agents act in the evolution of the basin fluvial geomorphology, how represented in the low stream, where the flooding bank and your low energy contribute to the landscape shaping.

Groundwater delineation for sustainable improvement and development aided by GIS, AHP, and MIF techniques

Exploration of groundwater is an integral part of viable resource growth for society, economy, and irrigation. However, uncontrolled utilization is mainly reported in urban and industries due to the increasing demand for water in semi-arid and arid regions of the world. In the background, groundwater demarcation for potential areas is vital in meeting necessary demand. The current study applied an integrated method comprising the analytical hierarchy process (AHP), multiple influence factors (MIF), combined with a linear regression curve and observatory well data for groundwater prospects mapping. Thematic maps such as flow direction, flow accumulation, elevation map, land use land cover, slope, soil texture, hill shade, geomorphology, normalized vegetation index, and groundwater depth map were generated utilizing remote sensing techniques. The relative weight of each parameter was estimated and then assigned to major and minor parameters. Potential zones for groundwater were classified into five classes, namely very good, good, moderate, poor, and very poor, based on AHP and MIF methods. A spatially explicit sensitivity and uncertainty analysis method to a GIS-based multi-criteria groundwater potential zone model is presented in this research. The study addressed a flaw in the way groundwater potential mapping results are typically presented in GIS-based multi-criteria decision analysis studies, where discrete class outputs are used without any assessment of their certainty with respect to variations in criteria weighting, which is one of the main contributors to output uncertainty. The study region is categorized based on inferred results as very poor, poor, marginal, and very good in potential ground quality 3.04 km2 is considered extremely poor, 3.33 km2 is considered poor, 64.42 km2 is considered very good, and 85.84 km2 is considered marginal zones, which shows reliable and potential implementation. The outcomes of AHP and MIF were validated by linear regression curve and actual water table in a study area. The study results help to formulate the potential demarcation of groundwater zones for future sustainable planning and development of groundwater sources. This study may be helpful to provide a cost-effective solution to water resources crises. The current study finding may be helpful for decision-makers and administrative professionals for sustainable management of groundwater resources for present and future demands.

Morphodynamics of a composite sand-cobble beach in response to extratropical cyclone Fiona and seasonal wave variability

Climate change is driving higher coastal water levels, and models project accelerated future sea-level rise and coastal storm intensification. These dynamics paired with anthropogenic coastal alterations will drive drastic coastal change worldwide. Composite beaches with mixed sediment sizes warrant detailed study as these exhibit complex morphodynamics in response to changing hydrodynamics due to the distinct transport thresholds of different sediment types. This study uses a novel multi-method approach to investigate a composite sand-cobble beach in Atlantic Canada experiencing a shortening seasonal sand-covered period. Hydrodynamic forcing and associated beach changes were monitored over a focused eight-month period, while satellite-based visual imagery and reconstructed wave data were analyzed over longer periods. Results show that intra-annual wave energy changes drive sand dynamics, with reduced summer wave energy facilitating short-term deposition. Long-term positive trends were identified in late spring wave heights, which likely contribute to the shortening sand-covered period. Seasonal dynamics were overwhelmed by extratropical cyclone Fiona, which made landfall on September 24, 2022, generating significant wave heights up to 6.8 m in the bay, mobilizing sediment, and steepening cobble berms. A new index approach based on visual imagery facilitated the investigation of beach sand appearance/disappearance using the relative redness of sand compared to cobble. Finally, the UAV-based surveys yielded high-resolution orthomosaics and LiDAR-based elevation mapping, and highlighted pronounced longshore variability in erosion and deposition during Fiona. The beach mostly recovered to pre-storm conditions in <4 months, which indicates that proposed beach nourishment activities may only experience temporary success. The longer-term results showing a conversion of sand to cobble suggest that loss of sandy beach habitat is likely to increase, even without shoreline migration or coastal squeeze driven by sea-level rise.

Geographical information system based assessment of various renewable energy potentials in Nigeria

Nigeria’s energy transition plan is hinged on increasing the energy mix from renewable energy sources. An understanding of where the potentials of these renewable energy sources lie is very crucial to enhance quality and timely policy formulations, interventions and proper decision making. This paper aims at providing a holistic assessment of the potentials of key renewable energy resources; solar, wind, biomass and small hydro in Nigeria using ArcGIS; a geospatial analytical platform that provide data and visualizations of these potentials across the country. This paper focuses on the Inverse Distance weighting methodology which overlays various map shapefiles and spreadsheets containing relevant data such as; waterlines and water areas, road and rail networks, crop production, longitude and latitude, wind speeds, solar irradiation, elevation and other relevant map data, shape files for all the Nigerian states and local governments. These data are geo-processed to align the results to the exact locations as provided by their geographical positions stem coordinates. These interpolation results are further reclassed within standard limits for the various output parameters such as crops, forest areas, built-up areas, water bodies, shrubs/grasslands, barren lands and waterbodies to reveal suitability areas for siting the various renewable energy power generating plants.

Predication of the post mining land use based on random forest and DBSCAN.

Mine reclamation is one of the most important stages of the mining activities in line with the basic principles of sustainable development. In this study, different post-mining land uses are evaluated in the Hongliulin mining area, which is located in Shen mu country of China. 145 soil samples were collected in the May,2021 by using the soil auger, and the sampling depths were 0-20 cm. The sampling points contains 45 to be reclaimed samples and 100 existing classification land use types. 14 environmental factors including soil organic matter (SOM), total nitrogen (TN), available phosphate (AP), available potassium (AK), K, Slope steepness, curvatures, aspect, length, Topographic Wetness Index (TWI), NDVI and elevation were extracted and calculated based on laboratory test and digital elevation map. The random forest classier showed a great prediction capability, with only 1 miss-classified sample in the validation data-set, the accuracy of the classification model was 95%. The content of TN of C1 is 5 times more than C2 and 4 times more than C3. Also, the K value of C1 column is maximum and over 0.4, which means the soil particle is relatively smaller and the soil texture of it is sandy loam. In terms of the 45 to be reclaimed samples, 15 samples were classified into C1, 23 samples were classified into C2, 5 samples were classified into C3, 2 samples were classified into C4. The value of K and content of soil nutrients of the samples classified to be C1 column(C1-C) is maximum. The soybean and murphy were suggested based on the soil nutrients index and with the mining disturbance on cluster 2 of C1, the ground subsidence filling as well as soil nutrients increased strategy should be applied. The result may contribute to the land use planning and idle land utilization strategy.

Assessing the stability of the reservoir rim in moraine deposits for a mega RCC dam

&lt;abstract&gt; &lt;p&gt;Diamer Basha Dam is an under-construction, 272-meter-high, roller compacted concrete (RCC) dam on the Indus River in Pakistan. Once constructed, it will be the world's highest RCC gravity dam with a 105-kilometer-long reservoir. Most of the reservoir lies in unstable moraine deposits with steep slopes. Events like saturation during reservoir filling, alternate wetting, drawdown during reservoir operation, or a seismic event could trigger a large mass movement of these slopes into the reservoir to disrupt the dam functionality. This work identified the 15 most vulnerable slide areas using digital slope maps, elevation maps, and satellite imagery. Deterministic slope stability analysis was carried out on the identified sections under various stages of reservoir operation for static and seismic loading, using pseudo-static and dynamic analysis approaches. Probabilistic analysis was then performed using Monte Carlo simulation. The findings showed that most moraine deposits would collapse under reservoir filling, rapid drawdown, or seismic activity. Following the assessments, landslide susceptibility maps were generated, and an assessment of potential impacts, including the generation of dynamic waves, reservoir blockage, increased sediment loads, and reduced reservoir storage capacity, was also performed.&lt;/p&gt; &lt;/abstract&gt;

Geospatial Agricultural Incident Analysis for the State of Indiana

Highlights 29 recent agricultural-related fatalities or injuries occurring throughout the state of Indiana were analyzed using geospatial incident analysis. Proximity of each incident to nearby cellular towers was found through 5 and 10-mile spatial joins by their relationship with cellular towers, with no towers most likely to be found within 5 miles of a given incident and only one tower to be found within 10 miles of a given incident. Proximity of each incident to emergency services and the nearest hospital was performed through 5 and 10-mile spatial joins, with only one service provider most likely to be within the five-mile range of a given incident. Abstract. A total of 29 recent agricultural-related injuries and fatalities throughout the state of Indiana were identified and analyzed for their proximity to cellular towers and emergency medical services (EMS). The objective of this research was to identify relationships between selected agricultural incidents and the ability of the victim to successfully contact emergency services. The geographic information system (GIS) software ArcGIS Pro and ArcGIS Online were utilized for trend identification and analysis. Findings from this analysis showed that only one EMS provider was most likely to be found within five miles of a given incident location. This frequency increased to seven EMS providers when the proximity range was increased to ten miles of a given incident location. The analysis also showed that only one cellular tower was most likely to be within a 10-mile radius of a given incident. There were frequently no accessible towers within five miles of a given incident. In addition, identified incidents were overlaid on a digital elevation map (DEM) of Indiana for analysis on the relationship between elevation and the number of accessible cell towers in the area. Studies have confirmed that victims of serious agricultural-related injuries, especially while working alone, face significant barriers in alerting EMS of their need for assistance. Geospatial analysis techniques performed in this study can be utilized by other states to assess access to EMS and for larger-scale, agricultural incident analysis. These tools have the potential to improve detail in agricultural incident reporting. Keywords: Emergency, Emergency communication, Emergency response, Farm injury, Incident response GIS, Working alone.

The Western Han Dynasty Pyramids and their Orientation in TessaDEM Elevation Maps

The Western Han Dynasty Pyramids and their Orientation in TessaDEM Elevation Maps

Scheimpflug Tomography as a Predictor of Corneal Edema After Phacoemulsification in Fuchs Endothelial Corneal Dystrophy.

To determine if Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict the occurrence of corneal edema following uneventful phacoemulsification surgery in Fuchs endothelial corneal dystrophy (FECD). Observational prospective case-control study. Fifty FECD eyes (50 patients) with visually significant cataract: 25 with subclinical corneal edema (SCE) versus 25 without SCE. Preoperatively, FECD was clinically assessed, and only patients devoid of clinical corneal edema were enrolled. Utilizing the Mayo Clinic classification for subclinical corneal edema (SCE), eligible FECD eyes were stratified based on Scheimpflug imaging pachymetry map and posterior elevation map characteristics, including loss of regular isopachs, displacement of the cornea's thinnest point, and the presence of posterior surface depression, into two groups: Group A representing FECD with SCE, and Group B: FECD without SCE. One week postoperatively, clinical and tomographic evaluation was performed. Regression analysis was conducted to evaluate predictors of corneal edema after uneventful phacoemulsification surgery in both groups. All patients were successfully imaged before and 1 week after surgery. Visual acuity was significantly improved in both groups (P < 0.001). No postoperative clinical edema was observed in Group B, while 23 (92%) had mild edema and 2 (8%) had moderate edema in Group A. Both groups showed a significant increase in postoperative central corneal thickness (CCT) and thinnest corneal thickness (TCT) (both P < 0.001). Compared to Group B, Group A showed a significant central flattening of the anterior corneal surface (P = 0.007 and P = 0.04 for K1 and K2 respectively), and a significant increase in the postoperative posterior surface depression. Multivariate analysis showed that 94% of postoperative corneal edema could be predicted by the presence of preoperative posterior surface depression (P = 0.04, ARR = 5.8 (1.89-35.7)). Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict corneal edema after uneventful phacoemulsification surgery in FECD with subclinical corneal edema.

Evolution of a Surge Cycle of the Bering‐Bagley Glacier System From Observations and Numerical Modeling

AbstractThe Bering‐Bagley Glacier System (BBGS), Alaska, Earth's largest temperate surging glacier, surged in 2008–2013. We use numerical modeling and satellite observations to investigate how surging in a large and complex glacier system differs from surging in smaller glaciers for which our current understanding of the surge phenomenon is based. With numerical simulations of a long quiescent phase and a short surge phase in the BBGS, we show that surging is more spatiotemporally complex in larger glaciers with multiple reservoir areas forming during quiescence which interact in a cascading manner when ice accelerates during the surge phase. For each phase, we analyze the simulated elevation‐change and ice‐velocity pattern, infer information on the evolving basal drainage system through hydropotential analysis, and supplement these findings with observational data such as CryoSat‐2 digital elevation maps. During the quiescent simulation, water drainage paths become increasingly lateral and hydropotential wells form indicating an expanding storage capacity of subglacial water. These results are attributed to local bedrock topography characterized by large subglacial ridges that dam the down‐glacier flow of ice and water. In the surge simulation, we model surge evolution through Bering Glacier's trunk by imposing a basal friction representation that mimics a propagating surge wave. As the surge progresses, drainage efficiency further degrades in the active surging‐zone from its already inefficient, end‐of‐quiescence state. Results from this study improve our knowledge of surging in large and complex systems which generalizes to glacial accelerations observed in outlet glaciers of Greenland, thus reducing uncertainty in modeling sea‐level rise.

Corneal topographer using null-screen patterned within a quadrangular acrylic prism

In this paper, the use of four flat-null-screens forming a quadrangular prism setup is employed as a target for an experimental corneal topographer. Topographic maps of three reflective calibration spheres with different radii of curvature: 7.70 mm, 9.42 mm, and 6.20 mm, and the corneal surface evaluation of a volunteer subject are presented. The experimental setup is based on the null-screen method. Zonal reconstruction of the surface shape of the human cornea is obtained by numerical integration of the normal vectors. The corresponding elevation map was found fitting an spherical model to the recovered data. The differences obtained in radius of curvature were 0.02% or less for the calibration spheres, and the cornea under test showed a difference of 1.39% (0.6 diopters) compared to the value obtained with ORBSCAN topographer.

KEY TECHNOLOGIES FOR 1:10,000 RAPID MAPPING BASED ON GF-7 SATELLITE

Abstract. In order to solve the problems of low efficiency, high cost and long cycle of the traditional 1:10000 basic geographic information data production method (aerial photography combined with field mapping), this paper proposes a 1:10000 rapid mapping method based on GF-7 satellite data. It solves the key technical difficulties of automatic information recognition, extraction, integration and mapping of water body, building, road, vegetation, contour, and other elements. And an automatic software system of “image -&gt; patch -&gt; data -&gt; map” is developed, which realizes the rapid production of 1:10000 basic geographic information data products and improves the ability of high-precision basic geographic information resource construction.

СONSTRUCTION OF AN OPTIMAL ROUTE FOR OVERFLYING UNPREPARED LANDING PADS

The problem of constructing an optimal route for overflying unprepared landing pads by the unmanned aerial vehicle (UAV) helicopter type in purpose to choose a useful unprepared landing to make an emergency landing is considered. The description of mathematical models that form the basis of the optimal algorithm of unprepared landing pads overflying is given. The decision to fly to an unprepared landing pad is based on the probabilistic criterion that considers the next following information: the probability of availability of an unprepared landing pad, the probability of failure of the UAV’s helicopter type onboard system, the error of a digital elevation map (DEM) positional information, the error of the UAV’s helicopter type coordinates information and the flight specifications of the UAV helicopter type.The comparison of the computational time of the algorithms of unprepared landing pads overflying is completed. The combined approach to find an optimal route for overflying unprepared landing pads depending on the computational time to solve it is proposed to use. The results of a simulation modelling of the proposed optimal algorithm for the estimation of its efficiency under conditions of variability of parameters of the probabilistic loss function are presented.

Dissection indices and their distribution over Mongolia

The main objective of this study was to create much more accurate maps of the ‘dissection depth’ and ‘dissection density’ in Mongolia, considering both the vertical and horizontal directions. To achieve this, two digital evetation models (DEMs) were used: the MERIT DEM with a spatial resolution of 90 meters and the ASTER DEM with a resolution of 30 meters. Some adjustments were made to rectify errors in relatively flat areas. The entire territory of Mongolia was selected as the study area, resulting in the creation of 2,865,000 grids with a resolution of 1 km. For each grid, the minimum and maximum values, as well as the length of dissection, were estimated. Finally, an interpolation method was used for mapping the depth and density of the dissection. The utilization of digital elevation models in the dissection map has exposed certain inaccuracies in flat areas. Consequently, the MERIT DEM has been selected as the favored alternative. Furthermore, this study emphasizes the disparities between the dissection depth map and the relative elevation map, as both play a vital role in comprehending and applying the concept of dissection depth. The maps of the dissection density and depth have proven to be highly valuable in the field of geomorphological and landscape research, as well as in the classification of origin groups and typological classification.

Robust Time-of-Arrival Location Estimation Algorithms for Wildlife Tracking

Time-of-arrival transmitter localization systems, which use measurements from an array of sensors to estimate the location of a radio or acoustic emitter, are now widely used for tracking wildlife. Outlier measurements can severely corrupt estimated locations. This article describes a new suite of location estimation algorithms for such systems. The new algorithms detect and discard outlier time-of-arrival observations, which can be caused by non-line-of-sight propagation, radio interference, clock glitches, or an overestimation of the signal-to-noise ratio. The new algorithms also detect cases in which two locations are equally consistent with measurements and can usually select the correct one. The new algorithms can also infer approximate altitude information from a digital elevation map to improve location estimates close to one of the sensors. Finally, the new algorithms approximate the covariance matrix of location estimates in a simpler and more reliable way than the baseline algorithm. Extensive testing on real-world data involving mobile transmitters attached to wild animals demonstrates the efficacy of the new algorithms. Performance testing also shows that the new algorithms are fast and that they can easily cope with high-throughput real-time loads.

Geomorphic features of Lake Havasu with impacts on its water resource capacity

Wilson DC. 2024. Geomorphic features of Lake Havasu with impacts on its water resource capacity. Lake Reserv Manage. 40:93–108. Determining a reservoir’s available storage capacity and its possible rate of change over time through in-filling are 2 of many parameters needed to conduct efficient and flexible water delivery operations, particularly in cascading river-reservoir systems. This study focused on this issue through generating the first bathymetric elevation map of Lake Havasu on the Colorado River (CR) with enough detail to identify geomorphic features, including areas of deposition, to assess the current storage capacity of the reservoir. Two main areas of deposition were identified, the CR inlet delta and the Bill Williams River (BWR) delta at the reservoir’s northern and southern ends, respectively. The physical distribution of the CR inlet deposits well into the main reservoir and to some extent those of the BWR delta also may have been influenced by one episode of drastic water level lowering early in the reservoir’s history that probably re-mobilized sediments when fluvial dynamics temporarily resumed. High resolution sonar images compared with the CR channel position on a pre-reservoir topographic map, a sonar-generated reservoir bottom hardness map coupled with grain-size analyses of sediment samples, and modeling reservoir water level changes support this notion. Post-reservoir dam construction up both rivers has cut off sediment sources that historically reached Lake Havasu, effectively reducing sedimentation rates. Determined thicknesses of the sediment packages indicate that Lake Havasu has lost more than 7% of its available storage capacity since inception, which is an important parameter for adjusting management of water deliveries and storage in the Colorado River system.

The value of advanced flood models, damage costs and land use data in cost-effective climate change adaptation

Damage costs from coastal flooding are high and are expected to increase further due to rising sea levels. The associated risks suggest a need for developing methodologies and models to assess damage costs in coastal areas as a basis for decision-making on climate change adaptation. The accuracy of damage cost estimates is critical in cost-effective decision-making on adaptation measures, reflecting climate hazards, flood levels, and associated damage costs. However, detailed models require extended work compared to simpler models due to demands on input data, including land use, damage costs, and adaptation options and costs. In the paper, varying levels of resolution, damage costs and flood models are assessed for coastal flooding risks for two Danish urban areas. Two damage cost models are used: a detailed, context-specific model using local high-resolution land use- and flood damage cost data and a less detailed model with lower-resolution land use data and damage costs based on generic European cost curves. Two flood models are used for the assessment using the detailed damage cost model based on a dynamic and a static flood approach, respectively. For the coarser model, only a static flood model is used. Significant differences are identified between the modelling approaches: The flood area varies up to a factor of ten for static floods due to the digital elevation map (DEM) model alone and a factor of 17 when changing both the DEM and using a dynamic flood. Corresponding factors for resulting damage costs are four and five, respectively.

Simulation of the Impacts of Sea-Level Rise on Coastal Ecosystems in Benin Using a Combined Approach of Machine Learning and the Sea Level Affecting Marshes Model

Sea-level rise in Benin coastal zones leads to risks of erosion and flooding, which have significant consequences on the socio-economic life of the local population. In this paper, erosion, flood risk, and greenhouse gas sequestration resulting from sea-level rise in the coastal zone of the Benin coast were assessed with the Sea Level Affecting Marshes Model (SLAMM) using ArcGIS Pro 3.1 tools. The input features used were the Digital Elevation Map (DEM), the National Wetland Inventory (NWI) categories, and the slope of each cell. National Wetland Inventory (NWI) categories were then created using Support Vector Machines (SVMs), a supervised machine learning technique. The research simulated the effects of a 1.468 m sea-level rise in the study area from 2021 to 2090, considering wetland types, marsh accretion, wave erosion, and surface elevation changes. The largest land cover increases were observed in Estuarine Open Water and Open Ocean, expanding by approximately 106.2 hectares across different sea-level rise scenarios (RCP 8.5_Upper Limit). These gains were counterbalanced by losses of approximately 106.2 hectares in Inland Open Water, Ocean Beaches, Mangroves, Regularly Flooded Marsh, Swamp, Undeveloped, and Developed Dryland. Notably, Estuarine Open Water (97.7 hectares) and Open Ocean (8.5 hectares) experienced the most significant expansion, indicating submergence and saltwater intrusion by 2090 due to sea-level rise. The largest reductions occurred in less tidally influenced categories like Inland Open Water (−81.4 hectares), Ocean Beach (−7.9 hectares), Swamp (−5.1 hectares), Regularly Flooded Marsh (−4.6 hectares), and Undeveloped Dryland (−2.9 hectares). As the sea-level rises by 1.468 m, these categories are expected to be notably diminished, with Estuarine Open Water and Open Ocean becoming dominant. Erosion and flooding in the coastal zone are projected to have severe adverse impacts, including a gradual decline in greenhouse gas sequestration capacity. The outputs of this research will aid coastal management organizations in evaluating the consequences of sea-level rise and identifying areas with high mitigation requirements.

Using a Non-Contact Sensor to Delineate Management Zones in Vineyards and Validation with the Rasch Model.

The production of high-quality wines is one of the primary goals of modern oenology. In this regard, it is known that the potential quality of a wine begins to be determined in the vineyard, where the quality of the grape, initially, and later that of the wine, will be influenced by the soil properties. Given the spatial variability of the fundamental soil properties related to the potential grape production, such as texture, soil organic matter content, or cation exchange capacity, it seems that a uniform management of a vineyard is not the most optimal way to achieve higher grape quality. In this sense, the delineation of zones with similar soil characteristics to implement site-specific management is essential, reinforcing the interest in incorporating technologies and methods to determine these homogeneous zones. A case study was conducted in a 3.3 ha vineyard located near Évora, south of Portugal. A non-contact sensor (DUALEM 1S) was used to measure soil apparent electrical conductivity (ECa) in the vineyard, and later, a kriged ECa map was generated. ECa and elevation maps were utilised to delineate homogeneous zones (management zones, MZs) in the field through a clustering process. MZs were validated using some soil properties (texture; pH; organic matter-OM; phosphorous-P2O5; potassium-K2O; the sum of the exchange bases-SEB; and cation exchange capacity-CEC), which were determined from 20 soil samples taken in the different MZs. Validation was also performed using Rasch measures, which were defined based on the formulation of the objective and probabilistic Rasch model, integrating the information from the aforementioned soil properties at each sampling location. The comparison of the MZs was more evident with the use of the Rasch model, as only one value was to be employed in each MZ. Finally, an additional validation was conducted using a vegetation index to consider the plant response, which was different in each MZ. The use of a non-contact sensor to measure ECa constitutes an efficient technological tool for implementing site-specific management in viticulture, which allows for the improvement of decision-making processes by considering the inherent spatial variability of the soil.

Fracture Network Analysis of Karstified Subis Limestone Build-Up in Niah, Sarawak

Understanding complex carbonate fracture networks and karstification at various geological scales is challenging, especially with limited multi-scale datasets. This paper aims to reduce uncertainty in the fracture architecture of Central Luconia karstified reservoirs by narrowing observational gaps between seismic and well data by using the discrete fracture models of exposed limestone outcrops as analogues for the subsurface carbonate reservoir. An outcrop-based fracture network characterisation of a near-surface paleo-karst at Subis Limestone combined with lineament analysis was conducted to extract fracture parameters. The karst structure was first delineated using a digital elevation map and outcrop examination. Then, topology analysis was performed, following the creation of two-dimensional discrete fracture models. Two main fracture sets oriented northeast–southwest and northwest–southeast and 79 potential dolines were identified. Fracture intersections, northeast–southwest major orientations, and drainage systems highly influenced the karst features. The Subis Limestone fracture model revealed that the highest number of fractures and total length of fractures were concentrated in the northern part of the Subis Limestone build-up (X: 250–350, Y: 150–250) and became denser towards the northwest direction of the outcrop (X: 600–800). The fractures in the Subis paleo-karsts appear isolated, with I-nodes ranging from 0.74 to 0.94. Hence, it is crucial to incorporate matrix porosity into multiple scales of fracture network modelling to improve upscaling and the modelling of fracture–vug networks, as well as to minimise the underestimation of discrete fracture networks in fractured and karstified limestone.