On computing topographic characteristics of a mountainous catchment

1981 ◽  
Vol 11 (4) ◽  
pp. 768-774 ◽  
Author(s):  
Stanislaw J. Tajchman
Keyword(s):  
Land Surface ◽  
Three Dimensional ◽  
Mountain Regions ◽  
Topographic Analysis ◽  
Mountainous Catchment ◽  
Surface Configuration ◽  
Mountain Catchment ◽  
Topographic Characteristics ◽  
Automatic Reading ◽  
Three Dimensional Coordinate

This report provides a theory and results of its application for a topographic analysis of a mountain catchment in the Appalachian Mountains, U.S.A. The catchment was divided into triangular segments ([Formula: see text]; 1 acre = 0.405 ha) that were analyzed in the three-dimensional coordinate system; topographic parameters of each triangle were computed and their distribution was represented by isolines. Areas included in specified ranges of inclination and azimuth are given in a tabular form in hectares, and they can be located on maps with isolines of azimuth and inclination.The average gradient of slope inclination is greater on northeast- and north-facing slopes (0.32°/m) than on southwest- and south-facing slopes (0.17°/m).The method has potential for application in land ecological, hydrological, and meteorological studies where a mathematical description of land-surface configuration is needed. The development of a system for automatic reading the coordinates from maps and storing them for computer processing would bring nearer the possibility of using this method for detailed biogeophysical analyses of large mountain regions.

Study on Geomorphologic Spatial Information Mining and Application

2011 ◽  
Vol 250-253 ◽  
pp. 1236-1242
Author(s):  
Li Heng Liang ◽  
Li Xin Xing ◽  
Tong Lin Li ◽  
Hong Yan Jiang ◽  
Li Jun Jiang
Keyword(s):  
Land Surface ◽  
Spatial Information ◽  
Digital Elevation Models ◽  
Three Dimensional ◽  
Shuttle Radar Topography Mission ◽  
Digital Elevation ◽  
Elevation Data ◽  
Local Relief ◽  
Local Window ◽  
Three Dimensional Coordinate

Digital Elevation Models (DEM) implies numbers of geomorphologic spatial information. It not only includes the three-dimensional coordinate but also has unique texture information, which can describe the ‘true’ land surface adequately at relation of neighbors (plan) and relative (amplitude). We will use a method to study the wavelength characters by data mining and distribution of slope and local relief on the altitude steps through a local window. The Shuttle Radar Topography Mission (SRTM) collect detailed Digital Elevation Models(DEM) data between 60°N and 57°S, 80 percent for all land masses, and it provides reliable, high precision surface elevation data for us, suits to analyze efficiently landscape pattern. SRTM-DEM data simulate three-dimensional land surface with regular gridded matrix, and these discrete points are fit for spatial neighbors’ analysis and statistics, and convenient to geomorphologic pattern computation and analysis in digital computer. Geomorphologic pattern is influenced by Physical properties and human activities in a most direct way, but whilst it record numbers of geological evolution evidence, and these records provide some important information for climate change, geological and geographical processes and ecological environment researches in science. In this study, making the whole Jilin province as study object, we propose a fourth-order equation to approximate land as a continuous curved surface, association neighbors’ analysis method, utilize digital elevation matrix to validate an optimal statistic window, and subsequent study the area spatial distribution by parameterization and classification, get a satisfactory effect.

A Finite Element Model of the Human Knee Joint for the Study of Tibio-Femoral Contact

2002 ◽  
Vol 124 (3) ◽  
pp. 273-280 ◽  
Author(s):  
Tammy L. Haut Donahue ◽  
M. L. Hull ◽  
Mark M. Rashid ◽  
Christopher R. Jacobs
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Three Dimensional ◽  
Element Model ◽  
Maximum Pressure ◽  
Contact Behavior ◽  
Element Size ◽  
Solid Models ◽  
Flexion Extension ◽  
Three Dimensional Coordinate

As a step towards developing a finite element model of the knee that can be used to study how the variables associated with a meniscal replacement affect tibio-femoral contact, the goals of this study were 1) to develop a geometrically accurate three-dimensional solid model of the knee joint with special attention given to the menisci and articular cartilage, 2) to determine to what extent bony deformations affect contact behavior, and 3) to determine whether constraining rotations other than flexion/extension affects the contact behavior of the joint during compressive loading. The model included both the cortical and trabecular bone of the femur and tibia, articular cartilage of the femoral condyles and tibial plateau, both the medial and lateral menisci with their horn attachments, the transverse ligament, the anterior cruciate ligament, and the medial collateral ligament. The solid models for the menisci and articular cartilage were created from surface scans provided by a noncontacting, laser-based, three-dimensional coordinate digitizing system with an root mean squared error (RMSE) of less than 8 microns. Solid models of both the tibia and femur were created from CT images, except for the most proximal surface of the tibia and most distal surface of the femur which were created with the three-dimensional coordinate digitizing system. The constitutive relation of the menisci treated the tissue as transversely isotropic and linearly elastic. Under the application of an 800 N compressive load at 0 degrees of flexion, six contact variables in each compartment (i.e., medial and lateral) were computed including maximum pressure, mean pressure, contact area, total contact force, and coordinates of the center of pressure. Convergence of the finite element solution was studied using three mesh sizes ranging from an average element size of 5 mm by 5 mm to 1 mm by 1 mm. The solution was considered converged for an average element size of 2 mm by 2 mm. Using this mesh size, finite element solutions for rigid versus deformable bones indicated that none of the contact variables changed by more than 2% when the femur and tibia were treated as rigid. However, differences in contact variables as large as 19% occurred when rotations other than flexion/extension were constrained. The largest difference was in the maximum pressure. Among the principal conclusions of the study are that accurate finite element solutions of tibio-femoral contact behavior can be obtained by treating the bones as rigid. However, unrealistic constraints on rotations other than flexion/extension can result in relatively large errors in contact variables.

scholarly journals Numerical Network Modeling of Heat and Moisture Transfer through Capillary-Porous Building Materials

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1819
Author(s):  
Borys Basok ◽  
Borys Davydenko ◽  
Anatoliy M. Pavlenko
Keyword(s):  
Building Materials ◽  
Moisture Transfer ◽  
Three Dimensional ◽  
Total Pore Volume ◽  
Equivalent Diameter ◽  
Average Pore ◽  
The Difference ◽  
Three Dimensional Coordinate ◽  
Solid Liquid ◽  
Heat And Moisture

The article presents the modeling of the dynamics of the vapor-gas mixture and heat and mass transfer (sorption-desorption) in the capillary structure of the porous medium. This approach is underpinned by the fact that the porous structure is represented by a system of linear microchannels oriented along the axes of a three-dimensional coordinate system. The equivalent diameter of these channels corresponds to the average pore diameter, and the ratio of the total pore volume to the volume of the entire porous material corresponds to its porosity. The entire channel area is modeled by a set of cubic elements with a certain humidity, moisture content, pressure and temperature. A simulation is carried out taking into account the difference in temperatures of each of the phases: solid, liquid and gas.

scholarly journals The Challenge of the Urban Compact Form: Three-Dimensional Index Construction and Urban Land Surface Temperature Impacts

2021 ◽  
Vol 13 (6) ◽  
pp. 1067
Author(s):  
Han Yan ◽  
Kai Wang ◽  
Tao Lin ◽  
Guoqin Zhang ◽  
Caige Sun ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Form ◽  
Three Dimensional ◽  
Compact Form ◽  
Landsat 8 ◽  
Driving Mechanism ◽  
Building Density ◽  
Building Height

Cities are growing higher and denser, and understanding and constructing the compact city form is of great importance to optimize sustainable urbanization. The two-dimensional (2D) urban compact form has been widely studied by previous researchers, while the driving mechanism of three-dimensional (3D) compact morphology, which reflects the reality of the urban environment has seldom been developed. In this study, land surface temperature (LST) was retrieved by using the mono-window algorithm method based on Landsat 8 images of Xiamen in South China, which were acquired respectively on 14 April, 15 August, 2 October, and 21 December in 2017, and 11 March in 2018. We then aimed to explore the driving mechanism of the 3D compact form on the urban heat environment (UHE) based on our developed 3D Compactness Index (VCI) and remote sensing, as well as Geo-Detector techniques. The results show that the 3D compact form can positively effect UHE better than individual urban form construction elements, as can the combination of the 2D compact form with building height. Individually, building density had a greater effect on UHE than that of building height. At the same time, an integration of building density and height showed an enhanced inter-effect on UHE. Moreover, we explore the temporal and spatial UHE heterogeneity with regards to 3D compact form across different seasons. We also investigate the UHE impacts discrepancy caused by different 3D compactness categories. This shows that increasing the 3D compactness of an urban community from 0.016 to 0.323 would increase the heat accumulation, which was, in terms of satellite derived LST, by 1.35 °C, suggesting that higher compact forms strengthen UHE. This study highlights the challenge of the urban 3D compact form in respect of its UHE impact. The related evaluation in this study would help shed light on urban form optimization.

scholarly journals The SCALEX Campaign: Scale-Crossing Land Surface and Boundary Layer Processes in the TERENO-preAlpine Observatory

2017 ◽  
Vol 98 (6) ◽  
pp. 1217-1234 ◽  
Author(s):  
B. Wolf ◽  
C. Chwala ◽  
B. Fersch ◽  
J. Garvelmann ◽  
W. Junkermann ◽  
...  
Keyword(s):  
Land Surface ◽  
Three Dimensional ◽  
Observational Research ◽  
Spatial And Temporal Scales ◽  
Soil Variables ◽  
Boundary Layer Processes ◽  
Long Time ◽  
Modelling Studies ◽  
June July

Abstract ScaleX is a collaborative measurement campaign, collocated with a long-term environmental observatory of the German Terrestrial Environmental Observatories (TERENO) network in the mountainous terrain of the Bavarian Prealps, Germany. The aims of both TERENO and ScaleX include the measurement and modeling of land surface–atmosphere interactions of energy, water, and greenhouse gases. ScaleX is motivated by the recognition that long-term intensive observational research over years or decades must be based on well-proven, mostly automated measurement systems, concentrated in a small number of locations. In contrast, short-term intensive campaigns offer the opportunity to assess spatial distributions and gradients by concentrated instrument deployments, and by mobile sensors (ground and/or airborne) to obtain transects and three-dimensional patterns of atmospheric, surface, or soil variables and processes. Moreover, intensive campaigns are ideal proving grounds for innovative instruments, methods, and techniques to measure quantities that cannot (yet) be automated or deployed over long time periods. ScaleX is distinctive in its design, which combines the benefits of a long-term environmental-monitoring approach (TERENO) with the versatility and innovative power of a series of intensive campaigns, to bridge across a wide span of spatial and temporal scales. This contribution presents the concept and first data products of ScaleX-2015, which occurred in June–July 2015. The second installment of ScaleX took place in summer 2016 and periodic further ScaleX campaigns are planned throughout the lifetime of TERENO. This paper calls for collaboration in future ScaleX campaigns or to use our data in modelling studies. It is also an invitation to emulate the ScaleX concept at other long-term observatories.

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