Spatial recognition of a rock fall velocity model developed in C++ using Geographic Information Sciences (GIS)

2007 ◽  
Vol 16 (5) ◽  
pp. 771-784
Author(s):  
Ranjan Deka ◽  
A.K. Pachauri ◽  
Bharat Bhushan
Author(s):  
Kimberly M. Meitzen

Geography is the study of the earth, including the physical environment, humans, natural and cultural places/regions, and the complex relationships among human-environment interactions. Geography is relevant to the environmental sciences for many reasons but particularly for its focus on distributions of various environmental- and human-related interactions and the factors controlling such distributions over varied spatial and temporal scales. Geography as an applied discipline provides many field-based and geospatial computational methods, techniques, and tools for analyzing local to global earth surface interactions. Environmental science benefits from these contributions. Geography inherently spans the physical and social sciences, commonly integrating aspects of each as they influence one another. This selection of resources focuses on the subdisciplines of geography that are distinctly environmental, including applied and basic process-based physical geography, human-environmental interactions, geographic information sciences, and considerations of scale. Physical geography is the study of the natural environment and all the components and processes that interact across the earth’s surface to influence the distribution and development of natural phenomena, including weather, climate, landforms, soils, plants, and animals. Physical geography is traditionally subdivided by the three major research areas: climatology, geomorphology, and biogeography. Climatology is the study of weather and climate processes and energy fluxes and the factors that control spatial and temporal variations in temperature and precipitation; such controls range from local topographic influences to global wind and ocean current circulation patterns, to human-influenced climate change. Geomorphology is the study of landforms and the processes (water, wind, ice, tectonics, etc.) that shape different erosional and depositional features of the earth surface. Geomorphology includes (but is not limited to) the study of rivers, mountains, coasts, glaciers, and many other earth surface features and landscapes. Biogeography is the study of the distributions of plants and animals (avian, terrestrial, marine, and freshwater organisms), their interactions within an ecosystem or landscape, and the factors controlling their presence and resilience. Climatology, geomorphology, and biogeography can all be examined across a range of spatial and temporal scales, and there is often an emphasis on explaining and quantifying how natural phenomena within these disciplines change over space and time and how they are influenced directly and indirectly by humans. Human-environmental geography includes natural hazards, environmental management, nature-society interactions, and the global environment. Geographic information sciences include GIS (geographic information systems) and remote sensing technologies designed for studying the earth surface environment. Although not a distinct subdiscipline, the concept of scale and the spatial and temporal dimensions of scale are a central tenet of most geography research. Global environmental change, as influenced by physical and human influences and interactions, is a more recent area of study within geography that is rapidly evolving.


2015 ◽  
Vol 39 (3) ◽  
pp. 361-387 ◽  
Author(s):  
Eugene J. Farrell ◽  
Douglas J. Sherman

The fall velocity of natural sand grains is a fundamental attribute of sediment transport in fluid environments where particles may become partially or fully suspended. Several formulae have been proposed to calculate the fall velocity of particles in air, but there is considerable uncertainty about which is the most accurate or appropriate for a given set of environmental conditions. Five experiments that reported observations of fall velocity of different types of particles in air are described, evaluated, and compared. The experiment data were quality-controlled using four criteria: (1) particles had to have sufficient drop heights to attain their terminal fall velocity; (2) particles had to be in the range of sand sizes; (3) data identified as being problematic by the original authors were removed; and (4) particles comprise natural, irregular shaped sediments. The quality-controlled data were aggregated and analyzed using linear regression to obtain a relationship between grain size ( d, in mm) and fall velocity ( w0, in ms-1): [Formula: see text]. This is a statistically strong relationship with a coefficient of determination of 0.89 ( p < 0.001). This relationship can be regarded as a universal fall velocity model for natural, sand-sized particles falling through a static column of air. In terms of predictive analyses, our heuristic method outperforms alternative formulae and yields a better fit to the experimental data over the full range of sand sizes.


2013 ◽  
Author(s):  
Rick Nadkrynechny ◽  
Orvel Lynn Rowlan ◽  
Carolyn Cepuch ◽  
James F. Lea ◽  
James N. McCoy
Keyword(s):  

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