• Title/Summary/Keyword: topographic factors

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Development of Hill Housing Addatable to the Topographic Characteristics on Sloping Sites (경사지의 지형특성에 적합한 경사지주택 개발 계획)

  • Hyun, Taek-Soo
    • Journal of the Korean Institute of Rural Architecture
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    • v.14 no.1
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    • pp.57-66
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    • 2012
  • This study focuses on the applicability of hill housing design in accordance with topographic characteristics on sloping sites. The urgency for housing still exists but hill sites have to be planned by gradual development using 'all available land' within any particular community. However, there is a reaction towards being more closely involved with nature and landscape. Sloping and hill sites must be developed by intelligent and sensitive planning, integrating the existing environmental factors. The results of this study are as follows : 1. The conditions of location are regarded as the concepts of spactial configuration. It should be developed on the basis of awareness that nature and human beings exist together. 2. It is inevitable that the development of the hill housing should be performed prefer to the topographic characteristics. 3. Planning elements of ecological residental blocks which are possible for constructing on the hill site can be developed and applied, on the basis of geographical characteristics, by housing types.

Field measurements of wind characteristics over hilly terrain within surface layer

  • He, Y.C.;Chan, P.W.;Li, Q.S.
    • Wind and Structures
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    • v.19 no.5
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    • pp.541-563
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    • 2014
  • This paper investigates the topographic effects on wind characteristics over hilly terrain, based on wind data recorded at a number of meteorological stations in or near complex terrain. The multiply data sources allow a more detailed investigation of the flow field than is normally possible. Vertical profiles of mean and turbulent wind components from a Sodar profiler were presented and then modeled as functions of height and wind speed. The correlations between longitudinal and vertical wind components were discussed. The phenomena of flow separation and generation of vortices were observed. The distance-dependence of the topographic effects on gust factors was revealed subsequently. Furthermore, the canyon effect was identified and discussed based on the observations of wind at a saddle point between two mountain peaks. This study aims to further understanding of the characteristics of surface wind over rugged terrain. The presented results are expected to be useful for structural design, prevention of pollutant dispersion, and validation of CFD (computational fluid dynamics) models or techniques over complex terrains.

Relation Between Barelands and Topographical Factors (독나지(秃裸地)와 지형인자(地形因子)와의 관계(關係))

  • Kang, Wee Pyung
    • Journal of Korean Society of Forest Science
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    • v.18 no.1
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    • pp.13-16
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    • 1973
  • The article was carried out to study the relationships between the causes of barelands and topographic factors such as altitudes, slopes and bearings. Using the forest utility demarcation maps of 1 : 50,000 in scale and the aerial photographs drawn and taken by the Forest Resources Institute, Seoul, the areas of each bareland and the topographic factors were calculated from the maps and photographs and the critical causes of barelands were analyzed based on the various topographic factors. The results obtained were as follows: 1. There were some positive relation between area of barelands and slopes, and between area of barelands and altitudes. 2. However. there were no significant difference between number of barelands and altitudes, between number of barelands and slopes, between number of barelands and bearings, and between area of barelands and bearings.

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GIS Based Analysis of Landslide Effecting Factors in the Pyeongchang Area

  • Kim, Gihong;Won, Sangyeon;Kim, Dongmin
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.3
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    • pp.261-269
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    • 2014
  • Most areas in Gangwon-do are mountainous regions where causes heavy damages due to landslides. It is important to analyze basic factors influencing the cause of landslides in order to prevent such landslides. For this study, a landslide occurring site is extracted from aerial images taken after the landslide caused by typhoon 'Ewiniar' in Pyeongchang area 2006. Also, the overlay analysis with the topographic, forest, and soil maps in this area is performed using GIS based methods. In addition, the topographic, forest, and soil characteristics relating to the landslide factors are analyzed. As a result, large numbers of landslides occurred at a slope angle of $20^{\circ}-40^{\circ}$. In the case of the forest factors, there are close relationships between the artificial pine and larch forests and the frequency of landslides. The low forest density represents a weakness in landslides. In the case of the soil factors, a higher level in the surface soil with a type of sandy loam soil, a higher gravel content in subsoil, and a higher degree of acid rocks in soil parent materials cause higher frequencies in landslides.

Analysis of Topographical Factors in Woomyun Mountain Debris Flow Using GIS (GIS를 이용한 우면산 토석류 지형인자 분석)

  • Lee, Hanna;Kim, Gihong
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.5
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    • pp.809-815
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    • 2020
  • A number of investigations and studies have been conducted in various fields regarding the sediment disasters of Mt. Woomyeon that occurred in July 2011. We collected and compared the topographic information of the general points where debris flows did not occur and the collapse points where the debris flow occurred in order to find out the characteristics of the collapse points in Woomyeon mountain. The collected topographic information is altitude, curvature, slope, aspect and TPI(topographic position index). As a result of comparison, there were relatively many collapse points at an altitude of 210m to 250m, and at a slope of 30° to 40°. In addition, the risk of collapse was low in a cell where the curvature was close to 0, and the risk was higher in concave terrain than in convex terrain. In the case of TPI, there was no statistical difference between the general points and the collapse points when the analysis radius was larger than 200m, and there was a correlation with the curvature when the analysis radius was smaller than 50m. In the case of debris flows that are affected by artificial structures or facilities, there is a possibility of disturbing the topographic analysis results. Therefore, if a research on debris flow is conducted on a mountain area that is heavily exposed to human activities, such as Woomyeon mountain, diversified factors must be considered to account for this impact.

Prediction of Topographic Change in the Estuary of Nakdong River and Analysis of Its Contribution by External Force Condition (낙동강 하구 지형변화 예측 및 외력조건에 따른 기여도 분석)

  • Kim, Kang-Min;Lee, Joong-Woo
    • Journal of Navigation and Port Research
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    • v.43 no.1
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    • pp.64-71
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    • 2019
  • It is very important to understand the mechanism of estuary topographic changes for the study of estuary management and treatment methods. In this study, the effects from the land-side, such as rainfall, river discharge, sediment discharge, and sea side, such as tide, tidal current, wave and surface sediments related to the topographic changes of the Nakdong river estuary were investigated and analyzed. Based on the analyzed data, topographic modeling was performed to analyze the topographic change and contribution of external force conditions. As a result of numerical modeling, the topographic change showed that erosion that predominates in the water directly affected by the discharge of the estuary barrage. The deposition predominates in the indirectly affected tideland. As sediments moved along the water way being sorted and distributed by the wave, the deposition predominated in the front of the barrier island. Compared with the deposition dominance, which is the result of the topographic change prediction, the impact of each external force condition gives larger erosion. However, the combined impact of each external force condition showed deposition dominant. Therefore, the topographic changes of the Nakdong river estuary are considered to be the result of various complex external factors. The impacts of each external force condition show the different contribution to each comparison area. These results should be considered when establishing the estuary management method. It must be understood that this is the result of complex interactions.

Analysis of Steep slope Disaster Sites using Geographic Information System (GIS를 활용한 급경사지 재해현장 분석 -전북 무주군, 장수군, 진안군 중심으로-)

  • Lee, Min-Seok;Oh, Jeong-Rim;Park, Dug-Keun;Kim, Man-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.940-945
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    • 2010
  • There are human casualties that caused by slope-stability related disasters such as landslide and debris flow during typhoon and rainy season every year in Korea. These disaster sites can be analyzed systematically using digital topographic data and aerial photogrammetry. In this study, geographical factors such as slope degree, geology, height, and soil depth are analyzed in four landslide-disaster sites from Muju, Jinan, and Jangsu County based on digital elevation maps generated by ArcGIS. Each site showed different characteristics in geology and geography and it is found that GIS can be utilized for the visualization of steep-slope failure areas.

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Landslide Susceptibility Analysis of Clicap, Indonesia

  • Kim, I. J.;Lee, S.;Choi, J. W.;Soedradjat, Gatot Moch
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.141-143
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    • 2003
  • The aim of this study is to evaluate the susceptibility of landslides at Clicap area, Indonesia , using a Geographic Information System (GIS). Landslide locations were identified from field surveys. The topographic and geological map were collected and constructed into a spatial database using GIS. The factors that influence landslide occurrence, such as slope, aspect and curvature of topography, were calculated from the topographic database and lihology and fault was extracted from the geological database. Then landslide susceptibility was analyzed using the landslide-occurrence factors by likelihood methods. The results of the analysis were verified using the landslide location data. The GIS was used to analyze the vast amount of data efficiently . The results can be used to reduce associated hazards, and to plan land use and construction.

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Topographic Factors Computation in Island: A Comparison of Different Open Source GIS Programs (오픈소스 GIS 프로그램의 지형인자 계산 비교: 도서지역 경사도와 지형습윤지수 중심으로)

  • Lee, Bora;Lee, Ho-Sang;Lee, Gwang-Soo
    • Korean Journal of Remote Sensing
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    • v.37 no.5_1
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    • pp.903-916
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    • 2021
  • An area's topography refers to the shape of the earth's surface, described by its elevation, slope, and aspect, among other features. The topographical conditions determine energy flowsthat move water and energy from higher to lower elevations, such as how much solar energy will be received and how much wind or rain will affect it. Another common factor, the topographic wetness index (TWI), is a calculation in digital elevation models of the tendency to accumulate water per slope and unit area, and is one of the most widely referenced hydrologic topographic factors, which helps explain the location of forest vegetation. Analyses of topographical factors can be calculated using a geographic information system (GIS) program based on digital elevation model (DEM) data. Recently, a large number of free open source software (FOSS) GIS programs are available and developed for researchers, industries, and governments. FOSS GIS programs provide opportunitiesfor flexible algorithms customized forspecific user needs. The majority of biodiversity in island areas exists at about 20% higher elevations than in land ecosystems, playing an important role in ecological processes and therefore of high ecological value. However, island areas are vulnerable to disturbances and damage, such as through climate change, environmental pollution, development, and human intervention, and lacks systematic investigation due to geographical limitations (e.g. remoteness; difficulty to access). More than 4,000 of Korea's islands are within a few hours of its coast, and 88% are uninhabited, with 52% of them forested. The forest ecosystems of islands have fewer encounters with human interaction than on land, and therefore most of the topographical conditions are formed naturally and affected more directly by weather conditions or the environment. Therefore, the analysis of forest topography in island areas can be done more precisely than on its land counterparts, and therefore has become a major focus of attention in Korea. This study is focused on calculating the performance of different topographical factors using FOSS GIS programs. The test area is the island forests in Korea's south and the DEM of the target area was processed with GRASS GIS and SAGA GIS. The final slopes and TWI maps were produced as comparisons of the differences between topographic factor calculations of each respective FOSS GIS program. Finally, the merits of each FOSS GIS program used to calculate the topographic factors is discussed.