• Title/Summary/Keyword: Slope Map

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Analysis of Slope Stability by Using Remote Sensing and GIS in Ichon Basin (원격탐사와 지구정보시스템 (GIS)을 이용한 이천분지의 사면안정평가)

  • Won, Jong Suck;Lee, Young-Hoon
    • Economic and Environmental Geology
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    • v.30 no.3
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    • pp.241-248
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    • 1997
  • In this study, Ichon basin is selected as study area and regional analysis of geological structure are done by using lineament analysis. The factors which affects slope stability, are chosen, and integrated to database using GIS (Geoscientific Information System). Landsat TM band 4, 5 and 7 are choosen and processed by various image enhancement technique to analyse the regional geological lineaments. Spatial distribution of lineament is analysed through lineament density map and study area can be divided the eight structural domains. Considering environmental geological characteristics of study area, rating and weighting of each factors for slope stability analysis are determined and spatial analysis of regional slope stability is examined through overlaying technique of GIS. The result of areal distribution of slope stability shows that the most unstable area is all over Mt. Buksung, Mt. Daepo, Mt. Songrim and Mt. Yankak.

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A Study on Damage Scale Tacking Technique for Debris Flow Occurrence Section Using Drones Image (드론영상을 활용한 토석류 발생구간의 피해규모 추적기법)

  • Shin, Hyunsun;Um, Jungsup;Kim, Junhyun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.6
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    • pp.517-526
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    • 2017
  • In this study, we analyzed the accuracy of elevation, slope, and area to the damage scale of the debris flow using the drones to track the details of the debris flow that method was between the digital topographical map(1/5,000) method and GPS ground survey method. The results are summarized as follows. At first, in the comparison of elevation, the value by the drones was 3.024m lower than the digital topography map, but in case of slope the average slope was $1.20^{\circ}$ and the maximum slope was $10.46^{\circ}$ which was higher by the drones image. Secondly, the difference area is $462m^2$ between on the digital topographic map and the drones image was calculated high, because it is determined by reflecting the uplift of the terrain as a point that calculated more accurate than the digital topographic map. Therefore, when compared with the existing method, the drone image method was very effective in terms of time and manpower.

Analysis of Slope Stability by Using Remote Sensing and GIS Around Chungju Area (원격탐사와 지구정보시스템을 이용한 충주지역의 사면안정분석)

  • Shin, Hyunjun;Lee, Younghoon;Min, Kyungduck;Won, Joongsun;Kim, Younjong
    • Economic and Environmental Geology
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    • v.29 no.5
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    • pp.615-622
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    • 1996
  • Slope stability analysis was conducted using remote sensing and Geoscientific Information System (GIS) as a part of natural hazard assessment around Chungju area. Landsat TM band 5 and 7 which contain more information about geological structure and geography are chosen and processed to analyse regional geological structure. Through image processing technique such as PCA, HFF, edge detection and enhancement, regional lineament can be mapped and identified. The lineament density map is constructed based on summed length of lineaments per unit area and the study area can be divided into 7 structural domains. Various factors of slope stability analysis such as geology, slope aspect, degree of slope, landcover, water shed as well as characterized structural domain are constructed as a database of GIS. Rating and weighting of each factor for slope stability analysis is decided by considering environmental geological characteristics of study area. Spatial analysis of regional slope stability is examined through overlaying technique of the GIS. The result of areal distribution of slope stability shows that the most unstable area is all over Jaeogae-ni, Hyangsan-ni and Mt. Daedun.

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A Proposal for Risk Evaluation Method of Slope Failure due to Rainfalls (강우 시 사면 붕괴 위험도 평가에 관한 제안)

  • Chae, Jong-Gil;Jung, Min-Su;Tori, Nobuyaki;Okimura, Takashi
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.893-903
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    • 2008
  • A method for predicting surface failures which occur during heavy rainfall on mountain slopes is proposed by using the digital land form model that is obtained by reading altitude on a topographical map at 10m grid point space. A depth of a potential failure layer is assumed at each grid point. In the layer, an infiltrated water movement from cell to cell is modeled in the study (cell is a square of the grid). Infiltrated ground water levels which show the three dimensional effects of a topographical factor in an area can be hourly calculated at every cell by the model. The safety factor of every cell is also calculated every hour by the infinite slope stability analysis method with the obtained infiltrated ground water level. Failure potential delineation is defined here as the time when the safety factor becomes less than unity under the assumptions that effective rainfall is 20mm/h and continues 20 hours.

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A Study on the Distribution of Pinus thunbergii in the Korean Peninsula (한반도의 곰솔분포에 관한 연구)

  • Kim, Jung Un;Bong-Seop Kil
    • The Korean Journal of Ecology
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    • v.6 no.1
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    • pp.45-54
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    • 1983
  • A distribution map of black pine, Pinus thunbergii, in south Korea was prepared through field surveys. According to Mirov(1967), the range of black pine is limited in east Asia, Japan and Korea; its northern limit is at about 41。34' north and its southern limit on Takara island, south Kyushu, at 29。 north. According to the present map, its northern limit coincided with the isopath of warmth index 100 by Yim(1977). The density of pine in grid mesh, about 4 km * 4 km, was higher at costal area than that in inland area, and it was also higher at sea side slope than the opposite slope of the same mountain. This suggests that the ecological distribution of black pine is greatly affected by salt content of the soil or the optimal range of summed temperature for the pine growth.

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Pore Filling Theory of Liquid Phase Sintering and Microstrcture Evolution (액상소결의 기공채움 이론과 미세구조 발달)

  • 이성민
    • Journal of Powder Materials
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    • v.6 no.1
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    • pp.81-87
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    • 1999
  • Based on the pore filling theory, the microstructure evolution during liquid-phase sintering has been analyzed in terms of interrelationship between average grain size and relative density. For constant liquid volume fraction, the microsturucture trajectories reduced to a single curve in a grain size(x)-density(y) map, regardless of grain growth constant. The slope of curves in the map was inversely proportional to average pore size, while it increased fapidly with liquid volume fraction. Increase in pore volume fraction retarded the densification considerably, but showed marginal effect on the slope. The activation energy of densification was predicted to be the same as that of grain growth as long as the liquid volume fraction is constant for any temperature range studied. The present analyses on microstricture evolution may demonstrate the usefulness of pore filling theory and provide a guideline for process optimization of liquid-phase sintering.

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Landform and Drainage Analysis in Geoje-Do Using GIS (GIS를 이용한 거제도 지형 및 하계 분석)

  • Kim, Woo-Kwan;Lim, Yong-Ho
    • Journal of the Korean association of regional geographers
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    • v.3 no.2
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    • pp.19-35
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    • 1997
  • The purpose of this study is to find out the characteristics of landform in Geoje-Do using GIS and DTED data. The characteristics of landform in Geoje-Do are as follows; First, the height-range of Geoje-Do is $0{\sim}580m$, and the average elevation of it is 124m. Volcanic and granite region is mainly appeared at high elevation-region. But, we can't find out outstanding difference of elevation, according to its geology. The second. the slope-range of Geoje-Do is $0{\sim}52$ degree, and the average slope of it is 17.6 degree. The slope of volcanic and granite area is more steeper than any other region. But the results of analysis of the geology in Geojo-Do, don't show outstanding difference of the slope. The third, the area-rate of the aspect of Geoje-Do is almost same in all direction. And the area-rate of south-west direction is the highest. According to the geology of Geoje-Do, granite is distributed the most widely, and the area of volcanic and granite occupy 60% of entire island's area. According to analysis of influence of geology with elevation, geology has little relationship with elevation. According to analysis of geology and drainage network, streams are inclined to be developed well in Alluvium area. Drainage network is well developed throughout the entire island, except southeast area. The highest order of stream is 4 in 1:25,000 topographic map. The density of stream in Geoje-Do is very high, such as 1.6. The bifurcation-ratio of stream is also higher than 4 in all order. The length-ratio of stream is ranged from 1.24 to 3.25. According to the relationship between order and elevation. order is the greater, elevation is the lower. According to the relationship between order and slope, order is the greater, slope is the gentler. In this study, we use DTED Data, and compare it with topographic map data. According to the comparison, there is a little difference between DTED data and topographic map data. Therefore, to use DTED data in landform analysis, it is required coordinate matching process. This process is very important, and take very long time. Thus, if you use DTED in landform analysis, some processes are required. DTED data can be taken very easily, but its using is not simple. Because coordinate adjust is very hard work.

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Ecological Diagnosis on Mt. nam in Seoul, Korea (남산의 생태학적 진단)

  • 이창석;문정숙;김재은;조현제;이남주
    • The Korean Journal of Ecology
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    • v.21 no.5_3
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    • pp.713-721
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    • 1998
  • The effects of artificial interference on the vegetation landscape in Mt. Nam of Seoul, Korea were clarified by analysing the distribution of vegetation landscape element and the number and size of patch depicted as a vegetation map in terms of landscape ecological principles. The effects of artificial interference on vegetation were also confirmed from the environmental gradient analysis on plant community extended from the lowland to the peak of that mountain. Vegetation landscape elements were divided into plantation and secondary forest in actual vegtation map. The ratio of plantation to secondary forest was higher in the lowland below mid-slope and the southern slope. Most afforested land were occupied by Robinia pseudoacacia and Populus tomentoglandulosa, Pinus rigida, P. koraiensis, Metasequoia glyptostroboides, Alnus hirsuta and so on are localy planted. In addition, projects to replace those afforested trees by P. densiflora as a kind of campaign for "Restoration of the one original feature of Mt. Nam" or to replace those tree species by planting young Abies holophylla or P. koraiensis under the mature afforested trees are also carried out in recent years. In cases of secondary forest, the southern slope was dominated by P. densiflora and the northern one by Q. mongolica. But the lowland of the northern slope is dominated by P. densiflora as the same as that in the southern slope. Vegetation landscape elements in Mt. Nam were much simplified comparing with that of suburban area around Seoul. The number of patches, which reflects the degree of diverse artificial interference was more in the lower area than in the upper area and more in the southern slope than in the northern one. On the other hand, the size of patch showed the antagonistic tendency to that of the number of patch. As a result of environmental gradient analysis, vegetation distribution in Mt. Nam was different from that in suburban area around Seoul. For example, Alnus japonica community, Zelkova serrata community, and Carpinus laxiflora community, which is established in mountain comparatively rare in artificial interference disappeared in Mt. Nam. As a result of analysis on vegetational succession in P. densiflora community and Q. mongolica community, both communities showed a tendency of retrogressive succession differently from that in control site located in suburban area around Seoul. In addition, species composition of P. densiflora and Q. mongolica communities in Mt. Nam were also different from those in Mt. Surak located around Seoul. It was interpreted that those results were originated from the environmental pollution and excessive arti ficial interferences.rferences.

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Correction in the Measurement Error of Water Depth Caused by the Effect of Seafloor Slope on Peak Timing of Airborne LiDAR Waveforms (지형 기울기에 의한 항공 수심 라이다 수심 측정 오차 보정)

  • Sim, Ki Hyeon;Woo, Jae Heun;Lee, Jae Yong;Kim, Jae Wan
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.3
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    • pp.191-197
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    • 2017
  • Light detection and ranging (LiDAR) is one of the most efficient technologies to obtain the topographic and bathymetric map of coastal zones, superior to other technologies, such as sound navigation and ranging (SONAR) and synthetic aperture radar (SAR). However, the measurement results using LiDAR are vulnerable to environmental factors. To achieve a correspondence between the acquired LiDAR data and reality, error sources must be considered, such as the water surface slope, water turbidity, and seafloor slope. Based on the knowledge of those factors' effects, error corrections can be applied. We concentrated on the effect of the seafloor slope on LiDAR waveforms while restricting other error sources. A simulation regarding in-water beam scattering was conducted, followed by an investigation of the correlation between the seafloor slope and peak timing of return waveforms. As a result, an equation was derived to correct the depth error caused by the seafloor slope.

Characterization of Wetness Index in Western Area of Yangsan Fault, Sangbuk-myeon, Kyeongnam-do (경상남도 상북면 양산단층 서부지역에 대한 습윤지수 특성 연구)

  • Kim, Sung-Wook;Han, Ji-Young;Lee, Son-Kap;Kim, Sang-Hyun;Kim, Choon-Sik;Kim, In-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.904-909
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    • 2004
  • The study area adjoins with Yangsan fault in Sangbuk-myeon, Samsam-ri, Kyongsang-namdo and consist of the natural steep slope. After drawing data layer which have altitude by using digital topography data, it is converted to lattice DEM of $10m{\times}10m$ size. From this, gradient map of unit lattice, slant direction map and shadow relif map are made. Using flow apportioning algorithm, upper slope contributing area and wetness index by established lattice can be calculated. Area that have high wetness index shows lineament structure of northwest-southeast direction, and this agrees with shear fracture system. The result of electricity specific resistance survey in the study area shows that area of high wetness index has low electricity specific resistance anomaly. That is, wetness index conforms with distribution of fractured zone that accompanied chemical weathering of rock. Therefore, wetness index can be used as the method of detecting fractured zones and judging the stability of the area.

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