• Title/Summary/Keyword: Topographic Features

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Satellite-altimeter-derived East Sea Surface Currents: Estimation, Description and Variability Pattern (인공위성 고도계 자료로 추정한 동해 표층해류와 공간분포 변동성)

  • Choi, Byoung-Ju;Byun, Do-Seong;Lee, Kang-Ho
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.17 no.4
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    • pp.225-242
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    • 2012
  • This is the first attempt to produce simultaneous surface current field from satellite altimeter data for the entire East Sea and to provide surface current information to users with formal description. It is possible to estimate surface geostrophic current field in near real-time because satellite altimeters and coastal tide gauges supply sea level data for the whole East Sea. Strength and location of the major currents and meso-scale eddies can be identified from the estimated surface geostrophic current field. The mean locations of major surface currents were explicated relative to topographic, ocean-surface and undersea features with schematic representation of surface circulation. In order to demonstrate the practical use of this surface current information, exemplary descriptions of annual, seasonal and monthly mean surface geostrophic current distributions were presented. In order to objectively classify surface circulation patterns in the East Sea, empirical orthogonal function (EOF) analysis was performed on the estimated 16-year (1993-2008) surface current data. The first mode was associated with intensification or weakening of the East Korea Warm Current (EKWC) flowing northward along the east coast of Korea and of the anti-cyclonic circulation southwest of Yamato Basin. The second mode was associated with meandering paths of the EKWC in the southern East Sea with wavelength of 300 km. The first and second modes had inter-annual variations. The East Sea surface circulation was classified as inertial boundary current pattern, Tsushima Warm Current pattern, meandering pattern, and Offshore Branch pattern by the time coefficient of the first two EOF modes.

Analysis of Three Dimensional Positioning Accuracy of Vectorization Using UAV-Photogrammetry (무인항공사진측량을 이용한 벡터화의 3차원 위치정확도 분석)

  • Lee, Jae One;Kim, Doo Pyo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.37 no.6
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    • pp.525-533
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    • 2019
  • There are two feature collection methods in digital mapping using the UAV (Unmanned Aerial Vehicle) Photogrammetry: vectorization and stereo plotting. In vectorization, planar information is extracted from orthomosaics and elevation value obtained from a DSM (Digital Surface Model) or a DEM (Digital Elevation Model). However, the exact determination of the positional accuracy of 3D features such as ground facilities and buildings is very ambiguous, because the accuracy of vectorizing results has been mainly analyzed using only check points placed on the ground. Thus, this study aims to review the possibility of 3D spatial information acquisition and digital map production of vectorization by analyzing the corner point coordinates of different layers as well as check points. To this end, images were taken by a Phantom 4 (DJI) with 3.6 cm of GSD (Ground Sample Distance) at altitude of 90 m. The outcomes indicate that the horizontal RMSE (Root Mean Square Error) of vectorization method is 0.045 cm, which was calculated from residuals at check point compared with those of the field survey results. It is therefore possible to produce a digital topographic (plane) map of 1:1,000 scale using ortho images. On the other hand, the three-dimensional accuracy of vectorization was 0.068~0.162 m in horizontal and 0.090~1.840 m in vertical RMSE. It is thus difficult to obtain 3D spatial information and 1:1,000 digital map production by using vectorization due to a large error in elevation.

Elemental Composition of Authigenic Siderites in the Early Holocene Coastal Sediments, Western Coast of Korea and Their Depositional Implication (한국 서해 초기현세 퇴적물중 자생 능철석의 원소 성분과 퇴적학적 의미)

  • Cho, J.W.;Lim, D.I.
    • Journal of the Korean earth science society
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    • v.23 no.8
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    • pp.697-706
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    • 2002
  • Authigenic siderite grains, ranging 100 to 250-${\mu}$m in diameter, are abundant in an about 8,600-year-old sediment layer in Namyang Bay, west coast of Korea. The siderites exhibit the aggregated spherulitic morphology with well-developed rhombs on the grain surfaces. They consist mostly of FeCO$_3$ (average, 65%) and MnCO$_3$ (average, 22%) with low Mg/Ca ratio (less than 0.4) in their bulk composition. A series of compositional ternary discrimination diagrams, together with high Mn and low Mg contents, show that only meteoric porewater was involved in siderite precipitation, assuming that depositional environment of host sediment is an organic-rich freshwater system. Considering a series of results such as radiocarbon age, authigenic Mn-rich siderite and lithological features, siderite-hosting sediment (unit Tl) is interpreted as freshwater swamp or bog deposition, infilling the topographic depressions that locally existed before the formation of mid-to-late Holocene tidal deposits. Center-to-margin compositional variation within individual grain is very systematic; Mn and Ca decrease towards the margin of a siderite grain, while Fe and Mg increase. It suggests that the spherulitic siderites were precipitated in this sedimentary layer in a series during the early diagenesis of MnOx-FeOx reduction under steady-state.

Estuary Classification Based on the Characteristics of Geomorphological Features, Natural Habitat Distributions and Land Uses (하구의 지형적.자연서식지.이용개발특성에 따른 유형 분류)

  • Lee, Kang-Hyun;Rho, Baik-Ho;Choi, Hyun-Jeong;Lee, Chang-Hee
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.16 no.2
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    • pp.53-69
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    • 2011
  • Classification of estuaries based on their multi-component and multidisciplinary processes is important for the systematic management of estuaries. In this study, an integrated GlS-based analysis system including high resolution aerial photographies and topographic maps was used to classify 463 estuaries based on estuarine circulation pattern, geomorphological feature, natural habitat distribution and characteristics of land use. These estuaries were divided into two basic types, open and closed. Two hundred and thirty five systems were open estuaries comprising of forty one mountainous type (OM), eighty sevcn sandpit type (OS) and one hundred seven funnel type (OF). Each type of open estuary was further classified into three types based on habitat distribution and land use characteristics resulting in total ninc types of open estuaries. Two hundred and twenty eight estuaries were closed systems comprising of one hundred and forty four blocked type (CB directly) and eighty four lake type (CL, indirectly). CB type estuary was further classified into three types based on habitat distribution and land use characteristics. This estuarine classification scheme can be applied to provide a framework for effective management strategies of individual estuaries to estimate the management priority and strategy.

Distributions of the Temperature and Salinity in Kamak Bay (가막만의 수온과 염분의 분포)

  • LEE Kyu-Hyong;CHO Kyu-Dae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.1
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    • pp.25-39
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    • 1990
  • The distributions of the temperature and salinity in Kamak bay which has two channels and three sea bottom topographic parts were studied by taking the detailed hydrographic data at the ebb and flood during four seasons from May, 1988 to Feb., 1989. The general pattern of the distributions of characteristics which the temperature and salinity has in Kamak bay is basically formed by the topography and sea water movement of the bay. The changes of these distributions by seasons mainly come from the heating and cooling of the sea surface and the increase of the run-off. The bay has three remarkable water masses and the their general characteristics are follows: the inner bay water has a stagnation character influenced by the inland and the concave of the sea bottom in the north west, Yosu harbor water has an estuary character of the low salinity caused by the run-off of Somjin river and Yon Tung brooklet in the north east, and the outer bay water has an out-sea character, as it is located near by the big mouth in the south of the bay. The distributions of those water masses at the ebb and flood show some different features due to the flow patterns, and the daily changes of oceanic conditions at the vicinity of Hangdae-ri are so big that it may influence the habitation and production of the living things in the bay.

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Comparative Analysis of Wind Flows in Wind Corridor Based on Spatial and Geomorphological Characteristics to Improve Urban Thermal Environments (도시 열환경개선을 위한 공간지형적 특성에 따른 바람길 유동 비교 분석)

  • SEO, Bo-Yong;JUNG, Eung-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.20 no.2
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    • pp.75-88
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    • 2017
  • This study analyzed wind flows based on spatial and geomorphological characteristics of Daegu Metropolitan City. A three-stage analysis was performed, starting with a comparison of meteorological relationships between local wind direction (synoptic wind) and local wind flow. In the second stage the study area was subdivided into districts and suburban districts to analyze the relative change of local wind flow. In stage three, the formation of wind corridor for local wind flow, wind flow for the entire urban space, and spatial relationships between flows were verified comparatively using KLAM_21. Three results are notable, the first of which is a low correlation between synoptic wind of a region, and local wind, flow in terms of meteorology. Secondly, observations of local wind flow at five downtown districts and two suburban districts showed that there were diverse wind directions at each measurement point. This indicates that the spatial and geomorphological characteristics of areas neighboring the measurement points could affect the local wind flow. Thirdly, verifying the results analyzed using KLAM_21, compared to Atomatic Weather System(AWS) measurement data, confirmed the reliability of the numerical modelling analysis. It was determined that local wind flow in a city performs a spatial function and role in ameliorating the urban heat island phenomena. This indicates that, when an urban planning project is designed, the urban heat island phenomena could be ameliorated effectively and sustainably if local wind flow caused by immediate spatial and geomorphological characteristics is confirmed systematically and techniques are intentionally applied to connect the flows spatially within areas where urban heat islands occur.

Deformation of Moho in the Southern Part of the Korean Peninsula (한반도 남부 모호면의 변형 구조)

  • Shin, Young-Hong;Park, Jong-Uk;Park, Pil-Ho
    • Journal of the Korean earth science society
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    • v.27 no.6
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    • pp.620-642
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    • 2006
  • The Moho structure and its deformation in the southern part of the Korean Peninsula were estimated using gravity and topography data. Gravity signals from the upper and lower crust were separated using a filter that was computed from isostacy and elastic thickness. The result of this study shows three characteristic features of the Moho deformation. First, the Moho folding structure is parallel to SKTL (the South Korean Tectonic Line), which indicates positive association with the collision of the Yeongnam and Gyeonggi Massifs and repeated compression afterwards. In contrast, noticeable deformation of the Moho was not observed along the Imjingang Belt, which is interpreted as another continental collisional belt in the Korean Peninsula. Second, the Moho beneath the Gyeongsang Basin has remarkably risen; this seems to be the result from both the collisional compression and buoyancy caused by magmatic underplating. Third, the Moho deformation is shallowest in the east of the Taebaek Mountains and deepens toward the west, consistent with the topographic characteristic of the Korean Peninsula of "high east and low west". It can be interpreted as the results of the opening of the East Sea and Ulleung Basin. A tectonic explanation for this could be the ascent of the mantle induced by continental rifting and horizontal extension at the early stage of the opening of the East Sea. The Moho deformation model computed in this study correlates well with the earthquake distribution and crustal movement measured by GPS. We suggest that the compression along the SKTL is still exerted, consequently, the Moho deformation is active, although it may be weak.

The Post Occupancy Evaluation of the Universal Design Project on Geonjisan Forest Trail Jeonju City, South Korea (전주시 건지산 숲길 Universal Design 사업 이용후 평가)

  • Park, Sun-A;Lee, Myung-Woo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.40 no.6
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    • pp.60-69
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    • 2012
  • The project on Geonjisan Universal Design Forest Trail in Jeonju City was designed and constructed by an NGO called 'Jeonbuk Forest for Life' which was a winner for the '2008 Open Competition by the 'Committee for Greening Society' established in Korea Land Corporation. The purpose of this study is to evaluate the design satisfaction of UD forest trail. Post Occupancy Evaluation (POE) method was applied to measure the user satisfaction and the total number of users. The main result of the study were as follows: the major users of the Geonjisan UD forest trail were people aged over 60 years old(37%) and the main purpose of trail usage were to 'walk and rest'(51.5%) and to 'exercise and rehabilitation' (40.6%). Furthermore, the overall user rating for the UD forest trail design was "satisfied"(3.91 point in 5-point Likert Scale). The three most influencing factors of the overall user satisfaction were facility management, user conflict, and trail width and slope. About forty-five people were found to be End-user in the UD forest trail while six people were found as End-user in non-UD trails. Most importantly, the number of End-user observed on the UD forest trail was greater than the number found in non-UD forest trail. The result implies that the UD forest trail attracts more End-users and provides opportunity for gathering and interaction with the other users. Moreover, the satisfaction rate for the UD forest trail landscape is found to be high in Likert scale, which we can assume that the well-grown existing trees and topographic features as well as appropriately designed wood-paths influence the high satisfaction rate of the users. The POE of UD forest trail revealed the importance of universal design concept due to its convenient uses of the handicapped, old, weak, pregnant woman or children.

A Study on Village Names of Youngnam Provinces : the Cases of Changnyeong-Gun, Bonghwa-Gun and Namhae-Gun (영남지방 지명에 관한 연구 -창녕군, 봉화군, 남해군의 경우-)

  • Park, Tae-Hwa
    • Journal of the Korean association of regional geographers
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    • v.5 no.1
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    • pp.1-24
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    • 1999
  • This is a study on village names in a plain region of Changnyeong-Gun, a mountain region of Bonghwa-Gun and an island region of Namhae-Gun. The three regions differ in geographical features. The data are based on 455 village names in Changnyeong-Gun, 552 village names in Bonghwa-Gun and 275 village names in Namhae-Gun found in the 1 : 50,000 topographic map. The method of this study is to analyze the word structures of village names in the five basic concepts in geography : Man-Land(Natural Environment and Human Activities). Spatial Relation, Distribution, Region and Transition. The main results of this study are as follows: 1. Naming of villages are related to Natural Environment(41%), Human Activities(23%), Region(17%), Spatial Relation(13%), Distribution(5%), and Transition(3%). Of these six factors, Changnyeong-Gun is relatively dominant in village names related to Spatial Relations, Region and Transition ; Bonghwa-Gun Natural Environment and Namhae-Gun Human Activities and Spatial Relations. But the three Guns are absolutely dominant in village names related to Natural Environment and Human Activities. 2. A village name is divided into the specific name part(given name) and the generic name part(classified name). Names related to Human Activities, Spatial Relations, Distribution and Transition are more frequently found in the specific name part. Therefore, they are used as the given name of a village name. Whereas names related to Natural Environment and Region are more frequently found in generic name part, which means that they are used as the classified name of a village. 3. The word structure of a village name usually has two parts a frontal part(given name) and a rear part(classified name). The two parts have a particular pattern in the geographic concept when they are combined. 1) In the village names related to in their frontal part of the word structure, is more frequently combined as their rear part in Bonghwa-Gun, in Namhae-Gun and in Changnyeong-Gun. 2) In the village names related to in their frontal part of the word structure, is more frequently combined as their rear part in Changnyeong-Gun, in Namhae-Gun and in Bonghwa-Gun. Accordingly, Man(Human Activities) - Land (Natural Environment) can be considered the most important concept in the naming of villages, because the concept is most frequently used in the word structures of village names.

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A Study on the Improvement of River Management System Based on Riverbed Change Data Management Program for Utilization of Advanced Bathymetry Data (선진화된 하천측량자료 활용 및 관리를 위한 하상변동 자료관리 프로그램 기반의 하도유지관리체계 개선에 관한 연구)

  • Jo, Myung-Hee;Kim, Kyung-Jun;Kim, Hyun-Jung
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.3
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    • pp.115-125
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    • 2013
  • The systematic management of river is difficult due to various environmental factors such as season and terrain deformation. Especially, river terrain are rapidly changing by natural and anthropogenic factors such as torrential rain during the summer and river development projects. Thus in this conditions, building the advanced river management system is an essential condition to support the ongoing management of survey data and to acquire data regularly through river terrain survey in order to maintain an active river. The need to build an efficient system have been increased through the enhancement and advancement of River Management Geographic Information Systems(RIMGIS). In this study, database design system and Riverbed Change Data Management Program was developed for systematic management of new river terrain survey data and the efficient use of river data dynamic changes. The key features are construction of river survey data, cross and longitudinal section monitoring and analysis of riverbed change data. Maintenance tasks which can be utilized in river-based architecture was constructed. The expected results are to be able to manage river systematically, and utilization of river topographic survey data efficiently for river maintenance work.