• Title/Summary/Keyword: Topographic change

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Accuracy Improvements of DAM-Reservoir Storage Volume Estimation based on GIS (GIS기반에서 댐 저수량 산정의 정확도 향상)

  • Jeong, InJu;Moon, DooYoul;Jung, BeomSeok
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.2
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    • pp.136-144
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    • 2005
  • GIS analyzes various topographic feature in three dimensions using triangulated irregular network (TIN). This paper proposed a method that can analyze topographic features effectively in three dimensions. Method developed in this study can calculate earth-volume, the inundation volume, storage volume etc, effectively. We could reduce error than existing volume calculation methods in computing volume in addition to water level's change about each. Also, the develop method can improve accuracy in measuring the storage of reservoirs. Main result of this paper id to develop a efficient calculation method using contour and elevation data on digital map.

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Development of GIS-based Method for Estimating and Representing Stream Slopes Along the River Network (GIS 기반 하천경사 산정 및 하천망에 따른 표출 방식 개발)

  • You, Ho-Jun;Kim, Dong-Su;Yang, Sung-Kee
    • Journal of Environmental Science International
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    • v.21 no.6
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    • pp.725-738
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    • 2012
  • Recently, a variety of GIS-based tools enabling to generate topographic parameters for hydrologic and hydraulic researches have been developed. However, most of GIS-based tools are usually insufficient to estimate and visualize river channel slopes especially along the river network, which can be possibly utilized for many hydraulic equations such as Manning's formula. Many existing GIS-based tools have simply averaged cell-based slopes for the other advanced level of hydrologic units as likely as the mean watershed slope, thus that the river channel slope from the simple approach resulted in the inaccurate channel slope particularly for the mountain region where the slope varies significantly along the downstream direction. The paper aims to provide several more advanced GIS-based methodologies to assess the river channel slopes along the given river network. The developed algorithms were integrated with a newly developed tool named RiverSlope, which adapted theoretical formulas of river hydraulics to calculate channel slopes. For the study area, Han stream in the Jeju island was selected, where the channel slopes have a tendency to rapidly change the upstream near the Halla mountain and sustain the mild slope adjacent to watershed outlet heading for the ocean. The paper compared the simple slope method from the Arc Hydro, with other more complicated methods. The results are discussed to decide better approaches based on the given conditions.

Edge Vegetation Structure in the Chirisan National Park (지리산 국립공원의 주연부 식생구조)

  • 오구균;권태호;이규완
    • Korean Journal of Environment and Ecology
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    • v.5 no.1
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    • pp.68-78
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    • 1991
  • To investigate edge vegetation structure and species in the Chrisan National Park, filed survey was excuted from August to October, 1991 and the results were as follows. Importance values of species in lower layer were changed according to the distance from edge to forest interior at the northeastern slope of a highland. Change of vegetation structure was observed from edge up to 30m of forest interior and edge depth was estimated as 15~20m. The dominance and frequency of edge species seemed to be affected by the factors of altitude, aspect and topographic location. Especially, edge vegetation showed severe difference according to topographic location between a ridge and a foot of a mountain, and according to aspect between southern and northern slope above midslope region of a mountain. Comparing vegetation structure of lower layer for southern and northern slope, more no. of individuals and crown coverage were observed at northern slope, while more no. of species, species diversity and coverage of Sasa purpurascen at southern slope.

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Relationship Analysis between Topographic Factors and Land Surface Temperature from Landsat 7 ETM+ Imagery (Landsat 7 ETM+ 영상에서 얻은 지표온도와 지형인자의 상관성 분석)

  • Lee, Jin-Duk;Bhang, Kon Joon;Han, Seung Hee
    • The Journal of the Korea Contents Association
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    • v.12 no.11
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    • pp.482-491
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    • 2012
  • Because the satellite imagery can detect the radiative heat from the surface using the thermal IR (TIR) channel, there have been many efforts to verify the relationship between the land surface temperature (LST) and urban heat island. However, the relationship between geomorphological characteristics like surface aspects and LST is relatively less studied. Therefore, the geomorphological elements, for example, surface aspects and surface slopes, are considered to evaluate their effects on the change of the surface temperature distribution using the Landsat 7 ETM+ TIR channel and the possibility of the image to detect anthropogenic heat from the surface. We found that the surface aspect is ignorable but the surface slope with the sun elevation influences on the surface temperature distribution. Also, the radiative heat from the surface to the atmosphere could not be accurately recorded by the satellite image due to the surface slope but the slope correction process used in this study could correct the surface temperature under slope condition and the slope correction, in fact, was not influenced on the average temperature of the surface. The possibility of the anthropogenic heat detection from the surface from the satellite imagery was verified as well.

GIS based Water-pollutant Buffering Zone Management

  • Kim, Kye-Hyun;Yoon, Chun-Joo
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.506-506
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    • 2002
  • S. Korean Government has accelerating its efforts to enhance the quality of the drinking water. The Ministry of Environment has declared the law of securing water-pollutant buffering zone to minimize the inflow of the point and nonpoint sources into the drinking water sources. As a first phase of installing nationa-wide water-pollutant buffering zone, approximately 300km buffering zone has been delineated along the South and North Han river, the major drinking water sources for the capital area of S. Korea, which has the population of more than 12 millions. The buffering zone has the width of 1,000 meter for the special protection area, and 500 meter for the remaining area from both ends of the river. The major works have been done in three stages. Firstly, the boundaries lines of the buffering zone was delineated on the digital topographic maps. Secondly, the maps were overlayed with the cadastral maps to identify individual land parcels, the street address of the major pollutant discharging facilities, and all different types of pollutants including livestocks. Thirdly, the field work has been done as a verification. Once the buffering zone was generated, all the information for the buffering gone were created or imported from other government agencies including official land price, details of the major manufacturing facilities discharging considerable amount of pollutants, major motels and resorts, not to mention of restaurants, etc. Also, major livestock houses were located to identify the path of the pollutant inflow to the drinking water source. Further works need to be continued such as purchasing private lands within the buffering zone and change the land use in the efforts to decrease the pollutant amount and to provide more environmentally friendly space. Also, high resolution satellite imagery should be utilized in the near future as a cost-effective data source to update all the landuse activities within buffering zone.

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Landform Classification using Geomorphons (지형패턴(Geomorphons)을 이용한 새로운 지형분류방법)

  • KIM, Dong-Eun;SEONG, Yeong Bae;SOHN, Hak Gi;CHOI, Kwang Hee
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.4
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    • pp.139-155
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    • 2012
  • Most of previous landform classification methods using DEM compares the values between the center of the cell and the surrounding cells, which in turn, greatly depends on analysis scale. To overcome the problem of scale-dependency, a new classification scheme is developed, which is called "Geomorphons". Unlike the traditional approaches using DEM, Geomorphons is the way which compares the level with other cells against the criteria cell. As a pilot study, we classify the landforms of Pyeongchang-Gun in Korea. Then, we compare the result with the other methods such as Topographic Position Index. Through the systematic analysis, we obtain the following findings. First, Geomorphons can reduce the time for the classification of landforms because of using unsupervised classification. Second, Geomorphons is little dependent on change in the scale, which can provide a pilot tool for reconnaissance study for covering large area.

A Study on the Automated Algorithm for Legal Calculation of Weighted Average of Building Surface - Based on Rhino Grasshopper Using Digital Topographic Map Data - (건축물 지표면 가중평균 법정산정 자동화 알고리즘에 관한 연구 - 수치지형도 데이터를 이용한 Rhino Grasshopper 중심으로 -)

  • Choi, Se-Yeong;Song, Seok-Jae;Kim, Yong-Seong
    • Journal of KIBIM
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    • v.13 no.2
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    • pp.1-15
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    • 2023
  • Since the 1960s, the Korean Peninsula, which consists of 77.4 of the country's land and mountains, has seen a surge in demand for buildings due to population concentration due to urbanization and industrialization. Since then, the development of slopes has been inevitable due to the concentration and expansion of the city's population. When building a building on a slope, it is important to set the height of the surface. In this case, the means of regulating buildings in construction-related laws, such as the building closure ratio, floor area ratio, number of floors and total floor area of buildings, have an overall effect on buildings through the height of the surface. In the Korean Building Act, the setting of the height of the ground affects the calculation of the building height limit standard and the calculation of the underground floor, and it takes a long time to calculate. Therefore, the time required for attempts to change various design plans of buildings increases. The purpose of this study is to speed up the time required to calculate the weighted average of the surface when constructing buildings on slopes. In addition, the existing calculation process allows various design attempts compared to the same time given.

Site Selection for Geologic Records of Extreme Climate Events based on Environmental Change and Topographic Analyses using Paleo Map for Myeongsanimni Coast, South Korea (고지도 기반 환경변화연구 및 지형분석을 통한 명사십리 해안의 제4기 연안지대 이상기후 퇴적기록 적지선정)

  • Kim, Jieun;Yu, Jaehyung;Yang, Dongyoon
    • Economic and Environmental Geology
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    • v.47 no.6
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    • pp.589-599
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    • 2014
  • This study selected optimal sites in Myeongsasimni located in west coast of Korea for stratigraphic research containing extreme climate event during quaternary period by spatio-temporal analyses of changes in sedimentary environment and land use employing 1918 topographic map, 2000 digital terrain map, 1976 and 2012 air photographies. The study area shows no significant changes in topographic characteristics that hilly areas with relatively large variations in elevation are distributed over north and south part of the study area, and sand dues are developed along the coast line. Moreover, flat low lying areas are located at the back side of the sand dues. The movement of surface run off and sediment loads shows two major trends of inland direction flow from back sides of sand dunes and outland direction flow from high terrains inland, and the two flows merge into the stream located in the center of the study area. Two sink with individual area of $0.2km^2$ are observed in Yongjeong-ri and Jaryong-ri which are located in south central part and south part of the study area, respectively. In addition, sea level change simulation reveals that $3.4km^2$ and $3.64km^2$ are inundated with 3 m of sea level rise in 1918 and 2000, respectively, and it would contribute to chase sea level change records preserved in stratigraphy. The inundated areas overlaps well with sink areas where it indicates the low lying areas located in south cental and south part of the study area are identical for sediment accumulation. The areas with minimal human impact on sediment records over last 100 years are $3.51km^2$ distributed over central and south part of the study area with the land use changes of mud and rice field in 1918 to rice field in 2012. The candidate sites of $0.15km^2$ in central part and $0.09km^2$ in south part are identified for preferable locations of geologic record of extreme climate events during quaternary period based on the overlay analysis of optimal sedimentary environment and land use changes.

Analysis of bed change based on the geometric characteristics of channel cross-sections (유로 단면의 기하학적 특성을 이용한 하상변화량 분석)

  • Ko, Joo Suk;Lee, Kyungsu;Kwak, Sunghyun;Lyu, Siwan
    • Journal of Korea Water Resources Association
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    • v.53 no.12
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    • pp.1097-1107
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    • 2020
  • A methodology has been proposed to understand the spatiotemporal changes of the river topography through the longitudinal change of the geometric characteristics of the cross-sections and the properties related thereto. Three-dimensional spatial information of the riverbed was obtained through the detailed bathymetry survey using an acoustic echo sounder for the reach from Gumi Weir to Chilgok Weir in the Nakdong river. Geometric informations for the reference sections were extracted using the acquired bathymetry survey data. By comparing the geometric properties for the reference sections, it was possible to catch the topographic characteristics and its changes over a reach of the channel. Through comparison with past survey data, it was also possible to quantitatively grasp the amount of change in cross-sectional area and volumetric change of riverbed. It is expected that a quantitative evaluation of river topography changes will be possible by applying the method proposed in this study.

The Relationship Between Tree Radial Growth and Topographic and Climatic Factors in Red Pine and Oak in Central Regions of Korea (중부지방 소나무와 참나무류의 반경생장량과 지형, 기후 인자의 관계)

  • Byun, Jae-Gyun;Lee, Woo-Kyun;Nor, Dae-Kyun;Kim, Sung-Ho;Choi, Jung-Kee;Lee, Young-Jin
    • Journal of Korean Society of Forest Science
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    • v.99 no.6
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    • pp.908-913
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    • 2010
  • This study analyzed the impact of climatic and topographic factors on tree radial growth of Pinus densiflora and Quercus spp. in central regions of Korea. To find the relationship between annual tree radial growth and climatic factors, we took the core samples from individual trees and measured the tree radial width. On the assumption that the tree radial growth is related to the tree age, we estimated the radial growth by the tree age as an independent variable. Also, we estimated the standard growth, defined as the radial growth of trees aged 30. As results, we found the spatial auto-correlation in the radial growth of the red pine. Moreover, we also found the relationships between climatic and topographic and the standard growth using the GAM (Generalized Additive Model). Increase of temperature has negative impacts on the radial growth of Pinus densiflora, while it has positive impacts on the radial growth of Quercus spp.. On the other hands, increase of precipitation has negative impacts on the radial growth of both species. Lastly, we predicted the spatial distribution changes of Pinus densiflora and Quercus spp. using the temperature increase scenario and the Geographic Information System (GIS) based forest type map. We could predict that Pinus densiflora is more vulnerable than Quercus spp. to climate change so that the habitats of Pinus densiflora will be gradually changed to the habitats of Quercus spp. in eastern coastal and southern regions of Korea after 60 years.