Elevation Model Research Articles

An automatic approach for rill network extraction to measure rill erosion by terrestrial and low‐cost unmanned aerial vehicle photogrammetry

AbstractFor an erosion event (October 2016) occurred at the Sparacia experimental area (Southern Italy), both terrestrial and low‐altitude aerial surveys were carried out by consumer grade camera and quadcopter (low‐cost unmanned aerial vehicle [UAV]) to measure rill erosion on two plots with steepness of 22% and 26%. Applying the structure from motion (SfM) technique, the three‐dimensional digital terrain models (3D‐DTMs) and the quasi three‐dimensional models (2.5D‐digital elevation model [DEM]) were obtained by the two surveys. Furthermore, 3D‐DTM and DEM were built using the available aerial photographs (166) and adding 40 terrestrial photographs. For the first time, the convergence index was applied to high‐resolution rill data for extracting the rill network, and a subsequent separation into contributing and non‐contributing rills was carried out. The comparison among the three surveys (terrestrial, UAV, and UAV + terrestrial) was developed using two morphometric parameters of the rill network (drainage density and drainage frequency). Moreover, using as reference the weight of sediment stored on the tanks located downstream of the plots, the reliability of soil loss measurement by 3D models was tested. For both contributing and non‐contributing rills, the morphometric parameters were higher for the terrestrial than for UAV and UAV + terrestrial surveys. For both plots, SfM always provided reliable soil loss measurements, which were affected by errors ranging from −8% to 13%. Although the applied technique used a low‐cost UAV and a consumer grade camera, the obtained results demonstrated that a reliable estimate of rill erosion can be obtained in an area of interest.

The Marceño Agroecosystem: Traditional Maize Production and Wetland Management in Tabasco, Mexico

The marceño agroecosystem is based on traditional agriculture in the flooded areas of the alluvial plains of Tabasco, Mexico. In the marceño system, the native maize, called “mején”, is cultivated during the dry season using residual soil moisture. At physiological maturity, mején is tolerant to flooding. To estimate the potential area where marceño may be implemented, we characterized and defined the areas where it is practiced, using geographic information systems (GIS), and determined the bioclimatic variables of the sites where 16 species of wild plants associated with the management of the marceño grow. We also analysed areas of agriculture and livestock in relation to the cyclical floods. This information was used to generate a probability model of marceño occurrence through MaxEnt, which was superimposed on an elevation model (LiDAR) geoprocessed with GIS. The marceño was observed in 203 localities across eight municipalities of Tabasco (~2% of the state area), at elevations of 1–7 m. The calculated area with potential for implementation of the marceño is about 18.4% of the state area. The implementation of this agroecosystem on a wider area might be an alternative for local agriculture development and a strategy for ecological conservation and restoration of wetlands.

Effect of Ganoderma lucidum on memory and learning in mice

BackgroundIn traditional Chinese medicine Ganoderma lucidum is famous for its beneficial effect on nervous system. It was traditionally used to manage different neurological disorders. This study was designed to investigate the nootropic potential of the mushroom.MethodsNootropic activity was evaluated following the oral administration of two different doses (150 and 300 mg/kg) of ethanol extract of Ganoderma lucidum. Physostigmine (0.1 mg/kg) and Scopolamine (0.4 mg/kg) were used as positive and negative controls respectively. Distilled water was used as a control. Elevated plus maze and Morris water maze were used for the assessment of learning process. In elevated plus maze, initial transfer latency and retention transfer latency were assessed. In Morris water maze, TSTQ (time spent in target quadrant) and transfer latency were evaluated. For the assessment of locomotor activity, open field test was utilized. Furthermore, biochemical estimation of acetylcholinestrases (AchE) was performed by using Ellman’s method.ResultsThe results of the study show that the Ganoderma lucidum extract has significantly increased the time spent in target quadrant (TSTQ) and decreased the escape latency (EL) in Morris water maze model. Whereas, a decrease in the Initial Transfer Latency (ITL) and Retention Transfer Latency (RTL) was observed in elevated plus maze model. Conclusion: The present study showed that Ganoderma lucidum has physostigmine like effect on brain acetylcholinesterase (AchE) activity.

3D Simulation Modeling of UAV-to-Car Communications

In this paper, we propose a realistic model for simulating communications between unmanned aerial vehicles (UAVs), or drones, and ground vehicles, which can support mobile infrastructure to broadcast alerts in emergency situations. Three-dimensional positioning features should be considered in these simulations that involve UAVs and ground vehicles since communications links are not based on a flat surface. In fact, irregular terrains in the form of hills and mountains can greatly affect the communications by acting as obstacles that block radio signals partially or totally. Hence, in this paper, we propose a simulation model that conforms to this kind of communication and that was developed in the scope of the OMNeT++ simulator. The simulation results achieved showed a great degree of similarities with those results obtained in a real testbed for different scenarios. In addition, various path loss models and elevation models were considered to improve the level of realism of the simulation model.

Multicriteria Evaluation of Transport Plan for High‐Speed Rail: An Application to Beijing‐Xiongan

Beijing has an enormous transportation challenge: to relieve the extreme congestion that has arisen, largely due to overpopulation. To meet this challenge, the city administration has decided to extend its territory; a new city will be planned and built. This new city, Xiongan, will reduce the burden on the capital. A new high‐speed railway (HSR) line is designed to transport millions of people every day within less than an hour. This study applies the potential of Geographical Information Systems (GIS) and multicriteria methods, Analytic Hierarchy Process (AHP) and Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE II), to determine the best alternative of transportation for the new high‐speed railway line between Beijing and Xiongan, comparing different ones. The methodology consists of two stages. In the first stage remote sensing datasets such as ASTER DEM and LANDSAT images and GIS software such as ERDAS IMAGINE and ArcGIS have been used to determine settlement distribution, station location, elevation model, slope percentage, vegetation percentage, and route alignment for a new high‐speed railway line for better understanding of its spatial distribution pattern over the study area. The second phase of the study focusing on assessing the various alternatives of transportation has been determined, and three approaches to choosing the best alternative have been introduced. In the paper we examine criteria associated with travel and economic criteria: travel time, the number of train stops, public satisfaction with transport, the number of seats per day, connectivity, operating costs, profit, and the payback period. Six alternatives of transportation have been studied. The stops in Guan and stations in the metro’s rings have been investigated. In the second stage, the Analytic Hierarchy Process (AHP) and PROMETHEE II methods have been used to select the best alternative. The first approach uses only criteria related to the trip, as the criterion to choose the best alternative is the maximum of the net outranking flows by PROMETHEE II method; the second approach applies two independent criteria: the ratio of normalized operating costs and the normalized net outranking flows, and the ratio of the normalized payback period and the normalized net outranking flows; the third approach includes all defined criteria, and the criterion of choosing the best alternative is the maximum of net outranking flows as calculated by the PROMETHEE II method. The approaches have been analyzed with the purpose of comparing the results. The result indicates that it is expedient to have a station in Guan, which will increase the connection and connectivity among the cities while providing fast mobility options for a large number of inhabitants of Guan city. Furthermore, the result from Remote Sensing and GIS analysis demonstrates that the proposed high‐speed railway line will be environmentally sustainable and is economically/socially feasible and that it will certainly attract current and future passengers because of their needs.

Inundation Model Using UAV-derived Digital Elevation Data and PCRaster Dynamic Model in An Excessive Rainfall Event

Extreme weather reportedly occurred on 28th November 2017 caused by a cyclone called Cempaka. Categorized as extreme weather since this event triggered an excessive rainfall reaching 246.8 mm in a 24-hour. Consequently, some areas in Yogyakarta Special Region are inundated. This research attempts to model the inundation of excessive rainfall using GIS software, PCRaster. The study area is concentrated in Selopamioro and Sriharjo, where Opak and Oyo rivers meet. Elevation model and rainfall data are used as the principal data to model the inundation. Elevation model is derived from the Unmanned Aerial Vehicle (UAV) image, while, the rainfall data of a-24-hour hourly data from the Meteorological Agency is also used as an input. The elevation model works as a flow direction model and the rainfall amount plays as the flowing material. The original states of water of the river are not considered, thus the study merely describes how the certain amount of rainfall adds to the level height of terrain and modeled for 24 hours. The result maps are the area that experience of a-24-hour high intensity of rainfall. The study depicts the additional water level caused by rainfall and the concentration of excessive rainfall in the study area. This information is beneficial in order to alarm a similar future event.

Influence of temperature and light gradient on leaf arrangement and geometry in cucumber canopies: Structural phenotyping analysis and modelling

Accurate structural phenotyping analysis is essential to understand plant architectural adaptation strategy to environment change. The aim of this study was to analyze leaf arrangement and geometry influenced by azimuthally generated light gradient; and to simulate static and heterogeneous cucumber canopies using regression equations by considering more geometric parameters. Three continuous measurements of structural organ parameters were obtained to fit the organ initiation and expansion curves. Four measurements with three density treatments were obtained to validate model accuracy. To describe leaf distribution and orientation characteristics in more detail, azimuth and elevation models were introduced into canopy structure modelling. Leaf distribution frequency was simulated based on leaf area index and solar elevation angle while leaf elevation was simulated based on leaf azimuth and acropetal phytomer number. This study provides an important basis for structural phenotyping analysis of cucumber canopy, which is essential for more accurate functional-structural modelling in the future.

BDS Stochastic Modeling and Impact Analysis

Carrier phase measurements are always used in high precision situations. Though in short baseline case, double difference technic can eliminate most of the systematic errors, some errors still remain. The stochastic model of carrier phase describes its stochastic characters. By modeling stochastic model, the solution accuracy and stability can be improved. To investigate the impact of stochastic models, the elevation model and SNR model are established respectively for GEO, IGSO and MEO satellites. Based on these stochastic models, their impact on azimuth solution is analyzed. In this paper, the basic function model is first introduced. Then the single difference (SD) carrier phase model and the estimation method of SD residuals are proposed. Finally, the stochastic models are established based on experiment data and the impact of those models are analyzed.

A comparative analysis of wind resource parameters using WAsP and windPRO

ABSTRACTThis paper investigates the accuracy of the wind resource estimation for a site in a central India region using a latest licensed version of WAsP 11 and windPRO 3.1. Whole one year measured met mast wind data has been taken using anemometer and wind vane at 10 m and 25 m height, respectively above ground level. The digitized elevation and roughness model of the corresponding site shows the roughness class 4 (roughness length 1.2525 m). The wind data has been extrapolated up to 80 m height by using power and log law models which provide the power density near about 120 W/m2. As per the micro sitting guidelines for the virtual wind farm installation 5D X 7D mapping has been selected which Indicates the total power output by installing 8 Vestas V-90 1.8 MW wind turbine from WAsP is 31.561 GWh and from windPRO is 28.083 GWh.

A Bayesian hierarchical spatio-temporal rainfall model

ABSTRACTA Bayesian hierarchical spatio-temporal rainfall model is presented and analysed. The model has the ability to deal with extensive missing or null values, uses a sophisticated variance stabilising rainfall pre-transformation, incorporates a new elevation model and can provide sub-catchment rainfall estimation and interpolation using a sequential kriging scheme. The model uses a vector autoregressive stochastic process to represent the time dependence of the rainfall field and an exponential covariogram to model the spatial correlation of the rainfall field. The model can be readily generalised to other types of stochastic processes. In this paper, some results of applying the model to a particular rainfall catchment are presented.

Isolation, Characterization and Antianxiety Activity of Pentacosan-13-ol from Ferula sumbul Hook. Roots

Ferula sumbul Hook. (Apiaceae) has been traditionally used as a sedative in hysteria and other nervous disorders. Present study aims to isolate the antianxiety constituent(s) from F. sumbul roots using bioactivity guided fractionation approach. Dried coarsely powdered of F. sumbul roots were subjected to successive exhaustive Soxhlet extraction using petroleum ether, chloroform and ethanol. Finally, decoction of the marc was prepared using distilled water. The extracts were screened for antianxiety activity in mice using elevated plus maze model at three different dose levels. Chloroform extract, exhibiting significant antianxiety activity, was subjected to column chromatography to obtain 4 fractions (F1-F4) which were further evaluated for antianxiety activity. Column chromatography of F4 yielded 5 sub-fractions (F4.1-F4.5) and a white amorphous compound. All these were evaluated for antianxiety activity. Characterization studies elucidated the structure to be pentacosan-13-ol. The compound exhibited significant antianxiety activity at the dose of 20 mg/kg, po. Present study validates the traditional use of F. sumbul roots in nervous disorders. Pentacosan-13-ol is the antianxiety constituent of F. sumbul roots. This is the first report on antianxiety activity of F. sumbul roots.

A Model‐Based Unloaded Test Method for Analysis of Braking Capacity of Elevator Brake

In order to improve the inspection efficiency and accuracy of the braking capacity of the elevator brake being used, a novel method for analyzing the full‐loaded braking performance by using the unloaded braking performance is proposed, and a set of methods for measuring the braking torque is designed. Based on the analysis of the key factors that affect the mechanical performance of the elevator brake, the calculation model of the braking torque in the process of the emergency braking with the traction ratio of 2 : 1 is established, and the relationship between the braking torque and acceleration under different working conditions is analyzed. It is shown that, for the model assumed, the emergency braking torque is 1.56 times that of the static braking torque under 1.25 times the rated load. The braking torque increases linearly with the increase of braking acceleration. An elevator model being used is tested and calculated. The experimental results show that the braking acceleration measured by the experiment is 11.95% less than the theoretical value. And the analysis shows that, comparing with the traditional test method, the braking torque test method designed in this paper is more accurate and safe.

Stream bank and sediment movement associated with 2008 flooding, South Fork Iowa River

Stream bank erosion can damage riparian systems and impact the use of water downstream. Risks of bank erosion increase during extreme flood events, and frequencies of extreme events may be increasing under a changing climate. We assessed bank erosion within the South Fork Iowa River (SFIR) watershed caused by 2008 flooding, which set flood stage records in many eastern Iowa streams. Bank positions before and after 2008 were digitized using rectified aerial infrared imagery and overlaid. Differences in stream bank lines were mapped as polygons; those <4 m (13 ft) wide were deleted to eliminate polygons possibly formed by digitizing error. A high-resolution (2 m [6.6 ft] grid) elevation model was used to map elevation changes associated with both erosional and depositional polygons. We estimated that along three streams (SFIR, Tipton Creek, and Beaver Creek) with watershed areas of 20,000 to 36,500 ha (49,000 to 90,150 ac), the 2008 floods widened the channels by 0.5 to 1.1 m (1.6 to 3.6 ft), and about 8.5 ha (21 ac) of land was lost to become part of these channels. The volume and mass losses associated with this movement totaled 117,000 m³ (153,000 yd³), which comprised on average 1.1 Mg m⁻¹ (1 Mg m⁻¹ = 1.01 tn yd⁻¹) of stream length. Below the Tipton Creek confluence, the middle SFIR (58,500 ha [144,500 ac]) was widened by more than 4.4 m (14.4 ft), with about 8.1 Mg (8.9 tn) of sediment lost per meter of stream. The 2008 floods substantially altered these channels, but using images from helicopter flights from late 2008 and 2009, we found evidence that where riparian buffers were kept in ungrazed, grassy vegetation, there was less bank erosion than where grazed pastures lined these channels. Riparian management systems may reduce stream bank erosion even under extreme flooding.

Observation on Nonideality of Boiling Point Elevation and Microscopic Model

Observation on Nonideality of Boiling Point Elevation and Microscopic Model

Rainwater harvesting and green area retention potential detection using commercial unmanned aerial vehicles

The objective of this work is to use simple photogrammetry to evaluate rainwater harvesting and green area retention potential in Maribor, Slovenia city centre. Several sources of remote sensing data have been described and a field test with semi-professional drone was performed by means of computer evaluation of rainwater harvesting and green area retention potential. Some of the most important design parameters for rainwater harvesting systems as roof area and slope and available green areas were identified and evaluated. The results have shown that even semi-professional low budget drones can be successfully used for mapping areas of interest. The results of six-minute flight over twelve hectares of Maribor city centre were comparable with professional results of plane remote sensing. Image segmentation from orthomosaic together with elevation model has been used to detect roofs and green areas.

Active Tectonics Around Almaty and along the Zailisky Alatau Rangefront

AbstractThe Zailisky Alatau is a >250 km long mountain range in Southern Kazakhstan. Its northern rangefront around the major city of Almaty has more than 4 km topographic relief, yet in contrast to other large mountain fronts in the Tien Shan, little is known about its Late Quaternary tectonic activity despite several destructive earthquakes in the historical record. We analyze the tectonic geomorphology of the rangefront fault using field observations, differential GPS measurements of fault scarps, historical and recent satellite imagery, meter‐scale topography derived from stereo satellite images, and decimeter‐scale elevation models from unmanned aerial vehicle surveys. Fault scarps ranging in height from ~2 m to >20 m in alluvial fans indicate that surface rupturing earthquakes occurred along the rangefront fault since the Last Glacial Maximum. Minimum estimated magnitudes for those earthquakes areM6.8–7. Radiocarbon dating results from charcoal layers in uplifted river terraces indicate a Holocene slip rate of ~1.2–2.2 mm/a. We find additional evidence for active tectonic deformation all along the Almaty rangefront, basinward in the Kazakh platform, and in the interior of the Zailisky mountain range. Our data indicate that the seismic hazard faced by Almaty comes from a variety of sources, and we emphasize the problems related to urban growth into the loess‐covered foothills and secondary earthquake effects. With our structural and geochronologic framework, we present a schematic evolution of the Almaty rangefront that may be applicable to similar settings of tectonic shortening in the mountain ranges of Central Asia.

3D hemodynamic model of the murine uteroplacental vasculature to quantify role of spiral artery structure in elevated maternal angiotensinogen model

3D hemodynamic model of the murine uteroplacental vasculature to quantify role of spiral artery structure in elevated maternal angiotensinogen model

Nationwide Point Cloud—The Future Topographic Core Data

Topographic databases maintained by national mapping agencies are currently the most common nationwide data sets in geo-information. The application of laser scanning as source data for surveying is increasing. Along with this development, several analysis methods that utilize dense point clouds have been introduced. We present the concept of producing a dense nationwide point cloud, produced from multiple sensors and containing multispectral information, as the national core data for geo-information. Geo-information products, such as digital terrain and elevation models and 3D building models, are produced automatically from these data. We outline the data acquisition, processing, and application of the point cloud. As a national data set, a dense multispectral point cloud could produce significant cost savings via improved automation in mapping and a reduction of overlapping surveying efforts.

Study on the Permafrost Distribution Based on RS/GIS

Permafrost in Qinghai-Tibet Plateau is the world’s highest elevation and largest permafrost regions in the lower latitude. For its vast area and less measured data, traditional mapping methods rely on the observations of station have been largely restricted. So it is necessary to build permafrost distribution model. Based on the GIS, using the RS data as the main data source and considering the distribution characteristics of permafrost in Qinghai-Tibet Plateau, we build Multivariate analysis model. Considered the elevation, land-surface temperature, vegetation, soil moisture and surface albedo and other factors related to the permafrost distribution in Tibet Plateau, and selected the Qinghai Tibet highway as the study area to simulate the permafrost distribution. Compared with the Retrieval Model of Ground Temperature based on RS/GIS, elevation model and frost number model, it is found that simulation result of Multivariate analysis model fit best with the permafrost distribution map and it reflected the permafrost distribution well along the Qinghai-Tibet highway.

NUMERICAL STUDY OF WAVE RUN-UP AT PERMEABLE FIXED REVETMENT SLOPE

The numerical model of wave surface elevation and water filtration in the saturated-unsaturated porous medium is developed. The model uses to define the parameters of the wave run-up at the slope protected by the permeable fixed layer. The model shows the wave surface in the different times, including the wave run-up height at the slope and wave run-down. Also, the velocities in the upper protected layer as well in the soil body of the slope are defined. Model is verified with using of the published large-scale tests with the slopes protected by Elastocoast technology layers. The tests were carried out in the wave flume of Technical University Braunschweig. The numerical model may be applied to calculate the maximal waves run-up at the protected engineering and beach slopes in natural conditions.