Topographic Elevation Research Articles

Integration of GNSS, Total Station, and Grid Controls: An Analysis of Combined Effect of Elevation of Topography and Map Projection Distortion to Solve the Distance Discrepancy

Heterogeneous measurements from various surveying methods need to be integrated to accomplish any survey project. The use of Global Navigation Satellite System (GNSS) and Total Station (TS) to establish a control framework along with utilizing existing national grid controls, for any survey project has been the standard practice. However, the successful integration of GNSS, TS, and existing grid controls could be challenging at times. Both survey professionals, and surveying stakeholders would benefit from the successful augmentation of heterogeneous measurements from GNSS, TS, and existing grid controls in order to provide a control framework for their survey project. In the past, the distance discrepancy/mismatch of GNSS-derived distance which is obtained from indirect measurements from GNSS survey and TS distance which is ground-based direct measurements, has created confusion. Herein, we have analyzed in detail, the combined effect of elevation of topography and map projection's distortion on the distance; demonstrate the magnitude of combined effect by numerical examples; tested this formulation with real-world GNSS and TS measurements. This way we proposed a solution to solve distance discrepancy/mismatch between various survey methods. The magnitude of the combined effect would be substantial with higher elevations and longer distances and could cross the threshold of specified/required accuracy. The effect would be more pronounced in mountainous regions suggesting combined effect should be properly taken into account. Taking combined effect into consideration brings the compatibility and comparability of GNSS, TS, and existing grid controls together. Thus, allowing both survey professionals and surveying stakeholders to utilize the mix of GNSS, TS, and existing grid controls to achieve required precision and accuracy in an economical, timely, and easy manner.

Rasch validation of the Keratoconus End-Points Assessment Questionnaire in a Spanish population with keratoconus

ObjectiveTo carry out a methodologically complete validation of the Spanish version of the Keratoconus End-Points Assessment Questionnaire (KEPAQ) in a Spanish population with keratoconus. MethodsAnalytical, prospective study, including patients with keratoconus without previous surgical history, in which a measurement of quality of life was performed using the KEPAQ questionnaire, a complete exploration of the anterior pole and a corneal elevation topography with the Galilei G6 topographer. The evaluation of the psychometric characteristics of the scale in the studied population was carried out using Rasch modeling. ResultsA total of 140 patients with keratoconus were included, with a median age of 26.0 years, the majority (57.6%) being men. For the KEPAQ-E subscale, the median score was 69.3, with a reliability of 0.85 and an eigenvalue of the first contrast of 2.34. For the KEPAQ-F, the median score was 56.4, with a reliability of 0.88 and an eigenvalue of 2.00. All infit and outfit parameters were within normal limits for both subscales. A significant evaluation was found between the evaluations of both subscales (rho = 0.696; p < 0.001). The evaluations of the subscales and various clinical and tomographic characteristics showed a significant classification between them (p value between 0.048 y 0.001). ConclusionThe KEPAQ is a psychometrically robust and valid scale to evaluate quality of life in the Spanish population with keratoconus. This questionnaire can be easily used for both clinical and research aims.

A 2012–2021 high‐resolution glacier mass balance estimate for Icelandic ice caps based on ArcticDEM and ICESat‐2

AbstractIce caps are important water resources for Iceland and are threatened by climate change. Despite their importance and vulnerability, the geodetic glacier mass balance estimate for the recent decade lacks a high‐resolution result. To address this gap, we first co‐registered the 2012–2021 ArcticDEM (v4) strips with ICESat‐2 points acquired over off‐ice areas and evaluated the accuracy of the co‐registered DEMs. We then applied a per‐pixel weighted liner regression to the multi‐temporal ArcticDEM strips and generated a high‐resolution (2 m) glacier surface elevation change rate for six major Icelandic ice caps. Based on these estimates we calculated the geodetic mass balance. Additionally, we estimated the seasonal relative surface elevation changes using ICESat‐2 ATL06 data for the 2019 to 2021 period. The results showed the co‐registered ArcticDEM strips exhibit good accuracy, with a standard deviation of 1.15 m across the Icelandic ice cap regions. Between 2012 and 2021, Icelandic ice caps experienced a state of mass loss, with a surface elevation change rate of −0.57 ± 0.21 m/a, corresponding to a mass loss of −0.51 ± 0.02 m w.e/a. Spatial variability in glacier surface elevation changes among different Icelandic ice caps ranges −0.19 m/a to −0.75 m/a. The Langjökull ice cap exhibited the most severe glacier mass loss at −0.68 ± 0.006 m w.e/a. Furthermore, our observations indicate a change in seasonal trends occurred across all six ice caps from 2019 to 2021. Specifically, the glacier surface thickening decreased during the accumulation period, while the thinning rate increased during the ablation period. These findings highlight that ArcticDEM v4 strips provide new insights into the mass balance of Icelandic glaciers and will aid in making future water management decisions. Moreover, the high‐resolution surface elevation topography and change rates provided in this study may contribute to an improved understanding of the influence of glacier dynamics on glacier change.

Spatial targeted delivery of riboflavin with a controlled corneal iontophoresis delivery system in theranostic-guided UV-A light photo-therapy.

Seven human donor eye globes underwent corneal cross-linking using theranostic UV-A device with accessory corneal iontophoresis system for patterned delivery of a 0.22% riboflavin solution. Theranostic-guided UV-A light illumination assessed riboflavin distribution and treated corneas at 10 mW/cm2 for 9 min with a 5.0-mm beam size. Corneal topography maps were taken at baseline and 2-h post-treatment. Analysis utilized corneal topography elevation data, with results showing controlled riboflavin delivery led to a consistent gradient, with 40% higher levels centrally (248 ± 79 μg/cm3) than peripherally (180 ± 72 μg/cm3 at ±2.5 mm from the center). Theranostic-guided UV-A light irradiation resulted in significant changes in corneal topography, with a decrease in best-fit sphere value (-0.7 ± 0.2 D; p < 0.001) and consistent downward shift in corneal elevation map (-11.7 ± 3.7 μm). The coefficient of variation was 2.5%, indicating high procedure performance in achieving significant and reliable corneal flattening.

Groundwater Potential Zone Assessment Using Remote Sensing, Geographical Information System (GIS), and Analytical Hierarchy Process (AHP) Techniques in Fogera Woreda, South Gondar Zone, Ethiopia

The study was conducted to know the groundwater potential zones in Fogera Woreda, south Gondar zone, Ethiopia. Through the utilization of the analytical hierarchy process (AHP), remote sensing, and geographic information system (GIS), the study identified groundwater potential zones. Ten thematic layers were analyzed to delineate the groundwater potential zones, including land use and land cover (LULC), topographic wetness index (TWI), drainage density, lineament density, geology, slope, rainfall, elevation, and soil texture. By determining the relative importance of each thematic layer through AHP and combining all thematic layers through overlay analysis in a GIS environment, the study revealed a spatial variation in the distribution of groundwater potential zones. The results showed that excellent groundwater potentials cover 2.02% of the study area, moderate groundwater potentials cover 45.54%, poor groundwater potentials cover 51.2%, and extremely poor groundwater potentials cover 1.24% of the study area. The study provides valuable information that can be used for decision-making processes and the development of appropriate groundwater management strategies in the region.

Neotectonism and reactivation of tectonic elements in eastern part of Shillong Plateau, India: constraints from morpho-tectonic analyses

ABSTRACT The Shillong Plateau is the only elevated topography in the Himalayan foreland bounded and crisscrossed by several prominent faults and shear zones. The plateau is situated in a complex tectonic compressional set up, owing to which the fault systems both at the periphery and within tend to be neotectonically active. Due to the elevation difference of the plateau with the Brahmaputra and Meghna River valleys flanking it, coupled with the impervious lithologies present, an intricate network of drainage system has developed in the plateau. In this paper, morphometric and structural analyses of four selected drainage basins from the east-central part of Shillong Plateau have been carried out to comprehend the effects of neotectonic reactivation of fault systems and associated basin tilting which in turn controls the development of drainage pattern. This has led to the understanding of the effects of the ever-evolving fluvial landforms on the anthroposphere in this part of Indian sub-continent, where the agrarian-economy is completely dependent on the intricate fluvial systems.

Sedimentary evolutionary processes, architecture, and sedimentary model of a lobate shallow-water delta: insights from flume simulation experiments

By using equipment such as time-lapse cameras and 3D laser scanners, this study conducted flume simulation experiments to obtain topographic elevation, the amount of sediment increment, sedimentary cross sections, and other related data and diagrams. Quantitative software was then utilized for sedimentological analysis to clarify the depositional evolution, architecture, and depositional model of lobate shallow-water deltas. The research results show that under the influence of hydraulic conditions and main distributary channels, lobate shallow-water deltas primarily undergo three evolution stages: initial channel formation, distributary channel system formation, and continuous stable evolution stage. The architecture elements of lobate shallow-water deltas can be divided into distributary channels dominated by channel deposition, proximal river mouth bars, transitional bars, and distal bars. The lateral composition and downstream deposition of the river-bar combination are the main structural units of the shallow water delta. The proximal profile distributary channels exist in the form of thick channel sand bodies with multiple repetitive intercalation cycles, and thick proximal bar deposits form on both sides of the distributary channels. The bifurcation of distributary channels in the middle profile leads to a reduction in channel scale, while large-scale proximal bars still develop on both sides of the channel. In the distal profile, a substantial river mouth bar complex is formed at the break of the delta front slope, and with the gradual progradation of the delta, the river mouth bar deposition zone becomes flattened. Based on the insights of the flume simulation experiments, a sedimentary model for lobate shallow-water delta was established.

The Permian Cornubian granite batholith, SW England; Part 2: Gravity anomalies, structure, and state of isostasy

A new compilation of Bouguer gravity anomaly data has been used, together with forward and inverse modeling, to reappraise the structure, volume, and state of isostasy of the Cornubian batholith of SW England. We show the individual plutons that comprise the batholith are, on average, ∼10−11 km thick, are outward-sloping in their upper 2−3 km, and are underlain by roots which protrude downward into the middle crust. The batholith volume is estimated within the range of 76,367 ± 17,286 km3, significantly larger than previous estimates. Granite outcrops correlate with elevated topography, and mass balance calculations show that the mass deficiency of the granites relative to their host metasedimentary rocks is approximately equal to the mass excess of the topography relative to air. The existence of roots beneath individual plutons is in general agreement with predictions of an Airy model of isostasy and a depth of compensation that is within the crust rather than at the Moho. In addition, a middle crust compensation depth is compatible with the origin of the granites by heating and melting of metasedimentary rocks and with data from experimental rock mechanics which suggest that at the melting temperature and pressure of granite formation, deformation is likely to be plastic and controlled by glide along dislocations. During pluton emplacement the middle crust would, therefore, have acted as a mechanically weak layer, effectively decoupling the topography from any support it might otherwise have received from the lower crust and/or upper mantle.

Continental Residual Topography Extracted From Global Analysis of Crustal Structure

AbstractContinental topography is dominantly controlled by a combination of crustal thickness and density variations. Nevertheless, it is clear that some additional topographic component is supported by the buoyancy structure of the underlying lithospheric and convecting mantle. Isolating these secondary sources is not straightforward, but provides valuable information about mantle dynamics. Here, we estimate and correct for the component of topographic elevation that is crustally supported to obtain residual topographic anomalies for the major continents, excluding Antarctica. Crustal thickness variations are identified by assembling a global inventory of 26,725 continental crustal thickness estimates from local seismological data sets (e.g., wide‐angle/refraction surveys, calibrated reflection profiles, receiver functions). In order to convert crustal seismic velocity into density, we develop a parametrization that is based upon a database of 1,136 laboratory measurements of seismic velocity as a function of density and pressure. In this way, 4,120 new measurements of continental residual topography are obtained. Observed residual topography mostly varies between ±1 and 2 km on wavelengths of 1,000–5,000 km. Our results are generally consistent with the pattern of residual depth anomalies observed throughout the oceanic realm, with long‐wavelength free‐air gravity anomalies, and with the distribution of upper mantle seismic velocity anomalies. They are also corroborated by spot measurements of emergent marine strata and by the global distribution of intraplate magmatism that is younger than 10 Ma. We infer that a significant component of residual topography is generated and maintained by a combination of lithospheric thickness variation and sub‐plate mantle convection. Lithospheric composition could play an important secondary role, especially within cratonic regions.

Implementation of Proximal and Remote Soil Sensing, Data Fusion and Machine Learning to Improve Phosphorus Spatial Prediction for Farms in Ontario, Canada

One of the challenges in site-specific phosphorus (P) management is the substantial spatial variability in plant available P across fields. To overcome this barrier, emerging sensing, data fusion, and spatial predictive modeling approaches are needed to accurately reveal the spatial heterogeneity of P. Seven spatially variable fields located in Ontario, Canada are clustered into two zones; four fields are located in eastern Ontario and three others are located in western Ontario. This study compares Bayesian Additive Regression Trees (BART), Support Vector Machine regressor (SVM), and Ordinary Kriging (OK), along with novel data fusion concepts, to analyze integrated high-density spatial data layers related to spatial variability in soil available P. Feature selection and interaction detection using BART variable selection and Recursive Feature Elimination (RFE) for SVM were applied to 42 predictors, including soil-vegetation indices derived from PlanetScope multispectral imagery, high-density apparent soil electrical conductivity (ECa), and high-resolution topographic attributes derived from DUALEM-21S and a Real-Time Kinematic (RTK) global navigation satellite systems (GNSS) receiver, respectively. Modeling spatial heterogeneity of soil available P with BART showed higher accuracy than SVM and OK in both zones of this study when trained and tested on ground truth data from clusters of farms. A BART variable selection approach resulted in six auxiliary predictors of soil available P in the eastern zone, while only four predictors were selected to predict P in the western zone. RFE for SVM resulted in models with 15 and 12 auxiliary predictors in the eastern and western Ontario zones. Topographic elevation was the most influential predictor of soil available P in both zones. Compared with the SVM and OK methods, BART exhibited lower average RMSE values for individual fields of 1.86 ppm and 3.58 ppm across the eastern and western Ontario zones, respectively, along with higher R2 values of 0.85 and 0.83, respectively. In contrast, SVM had RMSE values for individual fields in the eastern and western Ontario zones, respectively, averaging 5.04 ppm and 7.51 ppm and R2 values of 0.27 and 0.43. RMSE values for soil available P in individual fields across the eastern and western Ontario zones averaged 4.77 ppm and 7.81 ppm, respectively, with the OK method, while R2 values averaged 0.19 and 0.44. The selection of suitable auxiliary predictors and data fusion, combined with BART spatial machine learning algorithms, have potential to be a useful tool to accurately estimate spatial patterns in soil available P for agricultural fields in Ontario, Canada.

Understanding flash flooding in the Himalayan Region: a case study

The Himalayan region, characterized by its substantial topographical scale and elevation, exhibits vulnerability to flash floods and landslides induced by natural and anthropogenic influences. The study focuses on the Himalayan region, emphasizing the pivotal role of geographical and atmospheric parameters in flash flood occurrences. Specifically, the investigation delves into the intricate interactions between atmospheric and surface parameters to elucidate their collective contribution to flash flooding within the Nainital region of Uttarakhand in the Himalayan terrain. Pre-flood parameters, including total aerosol optical depth, cloud cover thickness, and total precipitable water vapor, were systematically analyzed, revealing a noteworthy correlation with flash flooding event transpiring on October 17th, 18th, and 19th, 2021. Which resulted in a huge loss of life and property in the study area. Contrasting the October 2021 heavy rainfall with the time series data (2000–2021), the historical pattern indicates flash flooding predominantly during June to September. The rare occurrence of October flash flooding suggests a potential shift in the area's precipitation pattern, possibly influenced by climate change. Robust statistical analyses, specifically employing non-parametric tests including the Autocorrelation function (ACF), Mann–Kendall (MK) test, Modified Mann–Kendall, and Sen's slope (q) estimator, were applied to discern extreme precipitation characteristics from 2000 to 201. The findings revealed a general non-significant increasing trend, except for July, which exhibited a non-significant decreasing trend. Moreover, the results elucidate the application of Meteosat-8 data and remote sensing applications to analyze flash flood dynamics. Furthermore, the research extensively explores the substantial roles played by pre and post-atmospheric parameters with geographic parameters in heavy rainfall events that resulted flash flooding, presenting a comprehensive discussion. The findings describe the role of real time remote sensing and satellite and underscore the need for comprehensive approaches to tackle flash flooding, including mitigation. The study also highlights the significance of monitoring weather patterns and rainfall trends to improve disaster preparedness and minimize the impact of flash floods in the Himalayan region.

Precipitation, topography, and soil conservation measures determine the spatiotemporal pattern of sediment yield at the regional scale

Exploring the driving effects of control factors on changes in sediment yield from a watershed perspective is of paramount importance for refined watershed management. The objective of this research is to unveil the spatiotemporal variation of sediment yield in the Coarse Sandy Hilly Catchments (CSHC) region from 1956 to 2019 and further investigate the relationship between sediment yield and driving factors. The findings revealed that the mutation years of sediment load (SL) at Toudaoguai and Longmen stations were 1986 and 1996, respectively, with annual SL declining by 66.75 % and 79.04 % after the mutation. Water and sediment discharge at Toudaoguai station exhibited more consistent fluctuations over time, while water and sediment discharge at Longmen station remained relatively consistent before 1967, followed by an entirely inconsistent trend. The spatial pattern of the annual average specific sediment yield (SSY) indicated that the northwest watersheds had a relatively higher erosion rate compared to the southeast. Over time, the SSY of each watershed exhibited a decreasing trend. The SSY showed significant negative correlations with terrace, afforestation, topographic position index (TPI), grass planting (GP), and elevation, while demonstrating significant positive correlations with rainfall indicators and runoff depth. Changes in precipitation, topography, vegetation and engineering measures accounted for 58.5 % of the variance in SSY. The total impact of precipitation on SSY change was positive (standard path coefficient (SPC) = 0.567, P < 0.01), whereas the total impact of topography, vegetation measures, and engineering measures on SSY change was negative (SPC = -0.282, −0.231, and −0.087, respectively). This study quantified the impact of different types of controlling factors on sediment yield at the watershed level. The insights provided by these results can contribute to sustainable watershed management and the optimal allocation of soil and water conservation measures (SWCMs).

Climate and soil factors co-derive the functional traits variations in naturalized downy thorn apple (Datura innoxia Mill.) along the altitudinal gradient in the semi-arid environment

Plant functional traits are consistently linked with certain ecological factors (i.e., abiotic and biotic), determining which components of a plant species pool are assembled into local communities. In this sense, non-native naturalized plants show more plasticity of morphological traits by adopting new habitat (an ecological niche) of the invaded habitats. This study focuses on the biomass allocation pattern and consistent traits-environment linkages of a naturalized Datura innoxia plant population along the elevation gradient in NW, Pakistan. We sampled 120 plots of the downy thorn apple distributed in 12 vegetation stands with 18 morphological and functional biomass traits during the flowering season and were analyzed along the three elevation zones having altitude ranges from 634.85 m to 1405.3 m from sear level designated as Group I to III identified by Ward's agglomerative clustering strategy (WACS). Our results show that many morphological traits and biomass allocation in different parts varied significantly (p < 0.05) in the pair-wise comparisons along the elevation. Likewise, all plant traits decreased from lower (drought stress) to high elevation zones (moist zones), suggesting progressive adaptation of Datura innoxia with the natural vegetation in NW Pakistan. Similarly, the soil variable also corresponds with the trait's variation e.g., significant variations (P < 0.05) of soil organic matter, organic carbon, Nitrogen and Phosphorus was recorded. The trait-environment linkages were exposed by redundancy analysis (RDA) that was co-drive by topographic (elevation, r = −0.4897), edaphic (sand, r = -0.4565 and silt, r = 0.5855) and climatic factors. Nevertheless, the influences of climatic factors were stronger than soil variables that were strongly linked with elevation gradient. The study concludes that D. innoxia has adopted the prevailing environmental and climatic conditions, and further investigation is required to evaluate the effects of these factors on their phytochemical and medicinal value.

Stochastic in Space and Time: 1. Characterizing Orographic Gradients in Mean Runoff and Daily Runoff Variability

AbstractMountain topography alters the phase, amount, and spatial distribution of precipitation. Past efforts focused on how orographic precipitation can alter spatial patterns in mean runoff, with less emphasis on how time‐varying runoff statistics may also vary with topography. Given the importance of the magnitude and frequency of runoff events to fluvial erosion, we evaluated whether orographic patterns in mean runoff and daily runoff variability can be constrained using the global WaterGAP3 water model data. Model runoff data are validated against observational data in the contiguous United States, showing agreement with mean runoff in all settings and daily runoff variability in settings where rainfall‐runoff predominates. In snowmelt‐influenced settings, runoff variability is overestimated by the water model data. Cognizant of these limitations, we use the water model data to develop relationships between mean runoff and daily runoff variability and how these are mediated by snowmelt fraction in mountain topography globally. A global analysis of topographic controls on hydroclimatic variables using a random forest model was ambiguous. Instead, relationships between topography and runoff parameters are better assessed at the mountain range scale. Rulesets linking topography to mean runoff and snowmelt fraction are developed for three mid‐latitude mountain landscapes—British Columbia, European Alps, and Greater Caucasus. Increasing topographic elevation and relief together leads to higher mean runoff and lower runoff variability due to the increasing contribution of snowmelt. The three sets of empirical relationships developed here serve as the basis for a suite of numerical experiments in our companion manuscript (Part 2, Forte &amp; Rossi, 2024a, https://doi.org.10.1002/2023JF007327).

Tectono-stratigraphic evolution in the Paleocene Lishui Sag, East China Sea Shelf Basin

The tectonic evolution of the Lishui Sag in the East China Sea Shelf Basin significantly influences its sequence stratigraphy. By integrating seismic reflections, well logs and core data, this study examines the quantitative activity of the Lingfeng fault, sequence framework and sequence architecture in the Lishui Sag. The Paleocene succession is divided into one second-order sequence (SSQ1), three third-order sequences (SQ1–SQ3) and nine system tracts, representing a complete syn-rift evolution consisting of initial syn-rift, rift climax and late syn-rift stages. The results indicate that the differential activity of the Lingfeng fault shapes the basin structure and controls the subsidence centre, leading to prominent variations in the spatial distribution and filling of the sequence stratigraphy during different tectonic stages. The initial syn-rift sequence (SQ1), characterised by a low activity of the segmented Lingfeng fault, is primarily found in isolated small sub-sags. The rift climax sequence (SQ2), with increasing displacement and longer segmented fault zones, exhibits a wedge-shaped filling pattern with substantial topographic elevation differences. The late syn-rift sequence (SQ3) shows a gradual decrease in tectonic activity and uniform filling, with all system tracts within the sequences fully developed. The sequence architecture of the hanging wall in the Lishui Sag can be classified into fault-scarp and fault-slope type, whereas the sequence architecture of the hanging wall dip-slope can be classified into sedimentary slope-break and faulted slope-break.

Topographic Elevation’s Impact on Local Climate and Extreme Rainfall: A Case Study of Zhengzhou, Henan

The topography significantly influences local climate precipitation and the intensity of precipitation events, yet the specific differences in its elevational effects require further understanding. This study focuses on precipitation in Zhengzhou City, Henan Province, utilizing hourly data and a topographic elevation precipitation increment model to assess the impact of topography on local climate precipitation and extreme heavy rainfall events. The results indicate that the daily precipitation attributed to topographic elevation in Zhengzhou in July was 0.21 mm, accounting for 4.9% of the total precipitation. In the extreme heavy rainfall event on 20 July 2021 (“7.20” event), the precipitation due to topographic elevation reaches 48.7 mm, constituting 15.8% of the total precipitation. Additionally, numerical simulations using the Weather Research and Forecasting (WRF) model for the 20–21 July 2021 rainfall event in Zhengzhou show that the WRF model effectively reproduces the spatiotemporal characteristics of the precipitation process. The simulated topographic elevation precipitation intensity is 49.8 mm/day, accounting for 16.6% of daily precipitation, closely resembling observational data. Sensitivity experiments further reveal that reducing the heights of the Taihang Mountains and Funiu Mountains weakens the low-level easterly winds around Zhengzhou. Consequently, as the center of the heavy rainfall shifts northward or westward, the intensity of topographic elevation-induced precipitation decreases to 7.3 mm/day and 12.9 mm/day.

Industrial Building Structure Planning With Cranes

Industrial building structure planning complies with standards and regulations, such as Procedures for Earthquake Resistance Planning, Minimum Loads for Building Design, and Specifications for Structural Steel Buildings. Vertical and lateral loads are fundamental to the structure's load flow process. Industrial buildings handle roof, wind, earthquakes, crane, and wall loads. Structural design must consider these elements, including the choice of lateral force-resisting systems such as X-bracing. In determining building loads, including earthquake and wind loads, various parameters such as wind speed, exposure category, and other factors must be considered by standard requirements such as SNI 1727-2020 and SNI 1726:2019. Selection of site class, wind direction, topographic, and ground surface elevation factors are essential in determining wind loads. This research method focuses on supporting structures consisting of purlins and girts in the context of industrial buildings. Purlins, made from hot or cold rolled steel, generally use C and Z profiles. Girts, made from cold or hot rolled steel, have profile variations such as C, Z, or hollow square sections. The girt structure design process determines dimensions, rod sag, internal requirements, and sag rod capacity.

Application of topographic elevation data generated by remote sensing approaches to flood inundation analysis model

Application of topographic elevation data generated by remote sensing approaches to flood inundation analysis model

Fault activity in the San Gabriel Mountains, southern California, USA: Insights from landscape morphometrics, erosion rates, and fault-slip rates

Many studies use landscape form to determine spatial patterns of tectonic deformation, and these are particularly effective when paired with independent measures of rock uplift and erosion. Here, we use morphometric analyses and 10Be catchment-averaged erosion rates, together with reverse slip rates from the Sierra Madre−Cucamonga fault zone, to reveal patterns in uplift, erosion, and fault activity in the range front of the San Gabriel Mountains in southern California, USA. Our analysis tests two prevailing hypotheses: (1) the range front of the San Gabriel Mountains is at steady state, in which rock uplift balances erosion and topographic elevations are stable throughout time, and (2) that west-to-east increases in elevation, relief, erosion rate, and stream-channel steepness across the interior of the massif reflect a parallel reverse-slip rate gradient on the range-bounding Sierra Madre−Cucamonga fault zone. We show that although deviations from steady state occur, the range-front hillslopes and stream channels are typically both well-connected and adjusted to patterns in Quaternary uplift driven by motion on the range-front fault network. Accordingly, landscape morphometrics, 10Be erosion rates, and model erosion rates effectively image spatial and temporal patterns in uplift. Interpreted jointly, these data reveal comparable peak slip rates on the Sierra Madre−Cucamonga fault zone and show that they do not monotonically increase from west to east. Thus, the eastward-increasing gradients developed within the interior of the massif are not solely related to reverse slip on the range-front faults. Evaluated on shorter length scales (&amp;lt;10 km), morphometric data corroborate earlier descriptions of the Sierra Madre−Cucamonga fault zone as multiple individual faults or fault sections, with slip rates tapering toward fault tips. We infer that these patterns imply the predominance of independent fault or fault section ruptures throughout the Quaternary, though data cannot rule out the possibility of large, connected Sierra Madre−Cucamonga fault zone ruptures. Deeper in the hanging wall of the Sierra Madre−Cucamonga fault zone, secondary faults accommodate range-front uplift. Motion on these faults may contribute to active uplift of the highest topography within the massif, in addition to partly reconciling differences between geologic and geodetic Sierra Madre−Cucamonga fault zone reverse-slip rates. This study provides a new, unified perspective on tectonics and landscape evolution in the San Gabriel Mountains.

Mapping Groundwater Potential (GWP) in the Al-Ahsa Oasis, Eastern Saudi Arabia Using Data-Driven GIS Techniques

Searching for new sources of water is becoming one of the most important aspects of scientific research, especially in areas prone to drought, like Saudi Arabia. The study aim was to delineate groundwater potential zones within the Oasis of Al-Ahsa, in Saudi Arabia’s eastern region, and to identify the optimum factors that control the availability of groundwater zones. This was achieved through examining the effect of ten environmental variables on groundwater recharge, namely: slope, topographic wetness index (TWI), land cover (LC), elevation, lineament density (Ld), drainage density (Dd), rainfall, geology, and soil texture. The variables were prepared from a variety of data sources, including spatial data (i.e., DEM and Landsat-8 image), in addition to other complementing data sources for appropriate parameters extraction. Two weighted overlay methods were used, namely the simple additive weight (SAW) as well as the optimum index factor (OIF) in order to categorize the optimal set of parameters for computing GWP and identifying its zones. Two GWP maps were obtained and validated through comparison with the locations of existing wells at GWP zones. The study findings have assured the cogency of the SAW map, where it was found that nearly 45–48% of the resultant zones were characterized as in the “moderate” class, whereas around 21–37% of the entire zones area were classified within the “high” class. The soil texture parameter was determined as being the most influencing parameter for GWP mapping followed by the “geology” parameter; however, the “lineament density” (Ld) was the least important factor. Furthermore, the OIF method has facilitated the identification of the optimal parameter combination for delineating groundwater potential (GWP) zones, which included “Ld”, “land cover”, and “TWI”. The study findings and methodology can serve as a potential model for other similar regions, supporting sustainable water resource management locally as well as globally.