• Title/Summary/Keyword: Topographic Analysis

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Study of Rainfall-Runoff Variation by Grid Size and Critical Area (격자크기와 임계면적에 따른 홍수유출특성 변화)

  • Ahn, Seung-Seop;Lee, Jeung-Seok;Jung, Do-Joon;Han, Ho-Chul
    • Journal of Environmental Science International
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    • v.16 no.4
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    • pp.523-532
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    • 2007
  • This study utilized the 1/25,000 topographic map of the upper area from the Geum-ho watermark located at the middle of Geum-ho river from the National Geographic Information Institute. For the analysis, first, the influence of the size of critical area to the hydro topographic factors was examined changing grid size to $10m{\times}10m,\;30m{\times}30m\;and\;50m{\times}50m$, and the critical area for the formation of a river to $0.01km^2{\sim}0.50km^2$. It is known from the examination result of watershed morphology according to the grid size that the smaller grid size, the better resolution and accuracy. And it is found, from the analysis result of the degree of the river according to the minimum critical area for each grid size, that the grid size does not affect on the degree of the river, and the number of rivers with 2nd and higher degree does not show remarkable difference while there is big difference in the number of 1st degree rivers. From the results above, it is thought that the critical area of $0.15km^2{\sim}0.20km^2$ is appropriate for formation of a river being irrelevant to the grid size in extraction of hydro topographic parameters that are used in the runoff analysis model using topographic maps. Therefore, the GIUH model applied analysis results by use of the river level difference law proposed in this study for the explanation on the outflow response-changing characters according to the decision of a critical value of a minimum level difference river, showed that, since an ogival occurrence time and an ogival flow volume are very significant in a flood occurrence in case of not undertow facilities, the researcher could obtain a good result for the forecast of river outflow when considering a convenient application of the model and an easy acquisition of data, so it's judged that this model is proper as an algorism for the decision of a critical value of a river basin.

Analysis of Landslide Hazard Area using RS/GIS (RS/GIS를 이용한 산사태 위험지역 분석)

  • Lee Yong-Jun;Park Geun-Ae;Kim Seong-Joon
    • Proceedings of the KSRS Conference
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    • 2006.03a
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    • pp.202-205
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    • 2006
  • The objective of this study is to analyze the hazard-areas for landslide using GIS and RS. LRA (Logistic Regression Analysis) and AHP (Analytic Hierarchy Program) methods were used for evaluation of the hazard-areas by six topographic factors (slope, aspect, elevation, soil drain, soil depth, land use). These methods were applied to Anseong-si where frequent landslides were occurred mainly by the regional heavy rainfall. A landslide hazard-map of Anseong-si could describe into 7 hazard-grades. As results, LRA method was underestimated in higher grades areas, while AHP method was underestimated in lower grades areas. In order to evaluate the hazard-areas for landslides with accuracy, these results of each method were overlapped and the results of suggested method were compared with the historical landslide hazard records of KFRI (Korea Forest Research Institute).

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A PRODUCTION METHOD OF LANDSLIDE HAZARD MAP BY COMBINING LOGISTIC REGRESSION ANALYSIS AND AHP (ANALYTICAL HIERARCHY PROCESS) APPROACH

  • Lee, Yong-Jun;Park, Geun-Ae;Kim, Seong-Joon
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.547-550
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    • 2006
  • This study is to suggest a methodology to produce landslide hazard map by combining LRA (Logistic Regression Analysis) and AHP (Analytic Hierarchy Program) Approach. Topographic factors (slope, aspect, elevation), soil drain, soil depth and land use were adopted to classify landslide hazard areas. The method was applied to a 520 $km^2$ region located in the middle of South Korea which have occurred 39 landslides during 1999 and 2003. The suggested method showed 58.9 % matching rate for the real landslide sites comparing with the classified areas of high-risk landslide while LRA and AHP showed 46.1 % and 48.7 % matching rates respectively.

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A Study for Open Space System Establishment of Chonju City -Chiefly as Viewed the Concept of Specified Nodes & Corridors- (전주시 "오픈스페이스"체계 수립에 관한 연구: 특화된 결정점과 "코리도"개념의 도입을 중심으로-)

  • 최만봉;김재식
    • Journal of the Korean Institute of Landscape Architecture
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    • v.15 no.1
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    • pp.69-84
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    • 1987
  • According to the complexity and the pluralism of the modern cities, they are changing themselves into the multinoded and social - classless urban environments. The sudden drift of population to the cities is giving rise to the serious environmental problems, and the rapid increase of recreational needs among the citizen is changing the urban society into a leisure - oriented one. In order to coping with the abrupt change in the social and natural urban environments, the various fields of urban society should be co - ordinated. The study uses the green - city concept to get solves the incongruity of urban structure in Chonju City. The existing open space maps were drawn up by the various techniques such as the analysis of the topographic maps and collected data, the interpretation of the aero-photographs and the reconnaissance of site. The authors suggested the existing condition, and the problems and potentials of open space elements in Chonju City through the analysis of the existing condition maps. After synthesizing the contents of analysis, the 7u(hors established an exclusive open space system for Chonju City.

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Analysis of Corneal Topography in Keratoconus (원추각막의 각막지형도 분석)

  • Kim, Douk-Hoon
    • Journal of Korean Clinical Health Science
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    • v.4 no.3
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    • pp.652-661
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    • 2016
  • The analysis of cornea morphology using corneal topographers is a clinical practice for the diagnosis of keratoconus in contact lens fitting. The recently technique has developed with the possibility of achieving a great number of measuring points of both anterior and posterior corneal surfaces in cornea. Also these data are used to extract a series of topographic valuation indices that permit to offer the most exact clinical diagnosis of keratoconus in contact lens fitting. This study describes the technologies in which current corneal topographers are based on the morphological characteristics that the keratoconus status observe on corneal surface. Therefore, this paper can provide that the analysis of corneal topographers applied for the diagnosis of keratoconus in contact lens fitting.

Landslide Susceptibility Analysis Using Artificial Neural Networks (인공신경망을 이용한 산사태 취약성 분석)

  • 이사로;류주형;민경덕;원중선
    • Economic and Environmental Geology
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    • v.33 no.4
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    • pp.333-340
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    • 2000
  • The purpose of this study is to develop landslide susceptibility analysis techniques using artificial neural network and apply the newly developed techniques for assessment of landslide susceptibility to study areas, Yongin. Landslide locations detected from interpretation of aerial photo and field survey, and topographic, soil and geological maps of the Yongin area were collected. The data of the locations of land-slide, slope, soil texture, topography and lithology were constructed into spatial database using GIS. Using the factors, landslide susceptibility was analyzed by artificial neural network methods. The results of the analysis were verified using the landslide location data. The validation results showed satisfactory agreement between the susceptibility map and landslide location data.

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Three Dimensional Study of the Tidal Flat Geomorphology in the $K\breve{u}$m River Estuary by Multidate Image Analysis

  • Yoo, Hong-Rhyong
    • Korean Journal of Remote Sensing
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    • v.2 no.2
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    • pp.95-105
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    • 1986
  • The geomorophology of the tidal near $K\breve{u}$m river estuary on the west coast of Korea was studied using satellite images. There Landsat image of different tidal moment were geometrically corrected to be overlapped one another. Then topographic contours were extracted for the analysis with concept of 3-D. According to the morphological analysis, the tidal flats around $K\breve{u}$m river estuary area can be classified in three morphologically different groups: one is developped in a belt type along the shore; another is a delta type in the estuary; the other is developped between the shore line and islands. The morphological characteristics of the tidal flats in the study area seems to be mainly influenced by the tidal dynamics which are very storg on the weatern coastal zone of Korea. However the waves and human activities seem also to be important in some part of the area.

Consequence Analysis on the Leakage Accident of Hydrogen Fuel in a Combined Cycle Power Plant: Based on the Effect of Regional Environmental Features (복합화력발전소 내 수소연료 적용 시 누출 사고에 대한 피해영향범위 분석: 지역별 환경 특성 영향에 기반하여)

  • HEEKYUNG PARK;MINCHUL LEE
    • Transactions of the Korean hydrogen and new energy society
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    • v.34 no.6
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    • pp.698-711
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    • 2023
  • Consequence analysis using an ALOHA program is conducted to calculate the accidental impact ranges in the cases of hydrogen leakage, explosion, and jet fire in a hydrogen fueled combined cycle power plant. To evaluate the effect of weather conditions and topographic features on the damage range, ALOHA is executed for the power plants located in the inland and coastal regions. The damage range of hydrogen leaked in coastal areas is wider than that of inland areas in all risk factors. The obtained results are expected to be used when designing safety system and establishing safety plans.

Analysis of Subway Adjacent Area Pedestrian Networks using Weighted Accessibility based on Road Slope (구배 기반 가중 접근성을 이용한 역세권 보행 네트워크 분석에 관한 연구)

  • Ha, Eun Ji;Jun, Chul Min
    • Spatial Information Research
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    • v.20 no.5
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    • pp.77-89
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    • 2012
  • Walking is the most basic personal mobility and its importance and concern is ever increasing with the highlighting of a new paradigm, such as transit oriented development, sustainable development and revitalization of green transport. The existing analytical research on pedestrian network is using a pedestrian's moving distance to a destination and integration in space syntax theory as its representative accessibility factors. However, the uniplanar network moving distance fails to reflect topographic characteristics, so the moving distance could show a similar result value in case of the regions for analysis that have a similar network structure to each other. Accordingly, the aim of this study is to suggest a new analytical methodology on pedestrian network accessibility in consideration of the grade in pedestrian sections and a pedestrian's size. this study, in its analysis of a uniplanar pedestrian network moving distance, analyzed the pedestrian network moving distance in consideration of the grade in pedestrian sections, and even the pedestrian network moving distance in consideration of a pedestrian's size, and suggested the methodology on pedestrian network accessibility analysis in consideration of a more substantive pedestrian's characteristics. It is hoped that the methodology used by this study will be used as the methodology on pedestrian network analysis which can reflect topographic characteristics in the pedestrian network analysis, and take a more substantive pedestrian's movement into account.

Analysis of Land Cover Characteristics with Object-Based Classification Method - Focusing on the DMZ in Inje-gun, Gangwon-do - (객체기반 분류기법을 이용한 토지피복 특성분석 - 강원도 인제군의 DMZ지역 일원을 대상으로 -)

  • Na, Hyun-Sup;Lee, Jung-Soo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.17 no.2
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    • pp.121-135
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    • 2014
  • Object-based classification methods provide a valid alternative to traditional pixel-based methods. This study reports the results of an object-based classification to examine land cover in the demilitarized zones(DMZs) of Inje-gun. We used land cover classes(7 classes for main category and 13 classes for sub-category) selected from the criteria by Korea Ministry of Environment. The average and standard deviation of the spectrum values, and homogeneity of GLCM were chosen to map land cover types in an hierarchical approach using the nearest neighborhood method. We then identified the distributional characteristics of land cover by considering 3 topographic characteristics (altitude, slope gradient, distance from the Southern Limited Line(SLL)) within the DMZs. The results showed that scale 72, shape 0.2, color 0.8, compactness 0.5 and smoothness 0.5 were the optimum weight values while scale, shape and color were most influenced parameters in image segmentation. The forests (92%) were main land cover type in the DMZs; the grassland(5%), the urban area (2%) and the forests (broadleaf forest: 44%, mixed forest: 42%, coniferous forest: 6%) also occupied mostly in land cover classes for sub-category. The results also showed that facilities and roads had higher density within 2 km from the SLL, while paddy, field and bare land were distributed largely outside 6 km from the SLL. In addition, there was apparent distinction in land cover by topographic characteristics. The forest had higher density at above altitude 600m and above slope gradient $30^{\circ}$ while agriculture, bare land and grass land were distributed mainly at below altitude 600m and below slope gradient $30^{\circ}$.