• 제목/요약/키워드: Coastlines

검색결과 68건 처리시간 0.027초

Navigation and Find Co-location of ATSR Images

  • Shin, Dong-Seok;Pollard, John-K.
    • 대한원격탐사학회지
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    • 제10권2호
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    • pp.133-160
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    • 1994
  • In this paper, we propose a comprehensive geometric correction algorithm of Along Track Scanning Radiometer(ATSR) images. The procedure consists of two cascaded modules; precorrection and fine co-location. The pre-correction algorithm is based on the navigation model which was derived in mathematical forms. This model was applied for correction raw(un-geolocated) ATSR images. The non-systematic geometric errors are also introduced as the limitation of the geometric correction by this analytical method. A fast and automatic algorithm is also presented in the paper for co-locating nadir and forward views of the ATSR images by using a binary cross-correlation matching technique. It removes small non-systematic errors which cannot be corrected by the analytic method. The proposed algorithm does not require any auxiliary informations, or a priori processing and avoiding the imperfect co-registratio problem observed with multiple channels. Coastlines in images are detected by a ragion segmentation and an automatic thresholding technique. The matching procedure is carried out with binaty coastline images (nadir and forward), and it gives comparable accuracy and faster processing than a patch based matching technique. This technique automatically reduces non-systematic errors between two views to .$\pm$ 1 pixel.

Engineering characteristics and eco-cultural potential of spring in Jeju Island

  • Koh, Byoung Ryoun
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2019년도 학술발표회
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    • pp.218-218
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    • 2019
  • Jeju island has an area of $1,810km^2$ and is considered the largest island in South Korea. In Jeju Island the average annual precipitation is 1,957mm. About 54% of precipitation is estimated to be lost due to evapo-transpiration and direct runoff, and the remainder is recharged. Historically springs and puddles were the island's primary sources of water. However, after 1970 all sectors, including the urban and industrial sectors depended solely on groundwater as their water resource. As vast amount of water is being recharged the Island has many springs, especially near the coastlines. Historlcally, spring of Jeju Island formed village and make it possible to continue a life. Also it produces many values such as the spring related story, culture, tourism and ecosystems. Especially, the naturally rare phenomenon that about 900 springs appear over the whole area of Jeju Island makes it possible to call it as a natural heritage. As a result of this most springs have either been destroyed or been in the state of neglect. In some cases it has been observed that springs were preserved by nature, however majority of the cases saw springs losing their own nature as a result of abandonment. It was recorded that there were 911 springs in Jeju Island with most of them being distributed along the coast, which consequently increases their susceptibility to seawater intrusion. The objective of this study is therefore to analyze Eco-cultural and Engineering characteristics about springs in the island, highlighting its past utilization and reestablishing its potential as a source of spring.

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The Emergence of Early Polities and Communities on the Trans-Peninsular Routes in the Thai-Malay Peninsula

  • Pipad KRAJAEJUN
    • Acta Via Serica
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    • 제9권1호
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    • pp.33-66
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    • 2024
  • There is a lot of evidence of early port cities and small habitation sites along the Thai-Malay Peninsula's coastlines. These sites appeared on the trans-peninsular routes during the Maritime Silk Roads period, from 2,000 to 1,500 BP. The Thai-Malay Peninsula was mentioned in many documents as Suvarnabhumi (India), Aurea Chersonese (Greek), and Jin Lin (Chinese), meaning the Golden Land. Ptolemy's map displays that there were many port cities along this peninsula. It corresponds to the Milinda-panha, which depicts many port cities in Suvarnabhumi. Foreign documents primarily documented the presence of major port cities, while inland habitation sites received less recognition. This paper aims to reconstruct the trans-peninsular routes in order to understand their networks, connections, and roles. The second aim is to understand the hierarchy of each site. This paper will focus on two important settlements and high-value artifacts along three routes: the Kra Isthmus Route, the Pho Khao Thong and Tha Chana Route, and the Krabi to Surat Thani Route. I conducted an archaeological survey of these three routes and others during 2021-2023 under the Suvarnabhumi Studies Center, TASSHA Institute, and the Ministry of Higher Education, Science, Research, and Innovation.

거제시 마을 이름에 대한 자연지리적 해석 -지형.기상.토양 관련 마을 이름을 중심으로- (Interpretation of Physical Geographic Meaning of Village Names in Geoje City, South Korea)

  • 강희순;범선규
    • 한국지역지리학회지
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    • 제11권5호
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    • pp.368-382
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    • 2005
  • 본 연구는 거제시의 마을 이름 중에 그 명명 기반이나 유래가 자연환경, 즉 자연지리적 요소에 있다고 믿어지는 것을 가려낸 다음, 그 속에 담긴 의의를 고찰한 것이다. 거제시의 마을 이름 중에는 해당마을 일대의 특징 있는 지형 기상 토양 등을 명명기반으로 한 사례가 적지 않다. 특히 급사면의 산지가 넓고, 리아스식 해안이 발달한 거제도의 지형 특징이 뚜렷하게 반영되어 있다. 기상(기후)와 토양과 관련된 것으로 추정되는 관련 마을 이름도 여럿이어서 관심을 끈다. 자연지리적 특성이 부각된 마을 이름은 그 자체만으로도 의미가 있으며, 명명 주체인 주민들의 환경지각, 자연환경의 역사적 변천 등과 관련된 연구 자료로도 활용할 수 있다.

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Effects of Roughness and Vertical Wall Factors on Wave Overtopping in Rubble Mound Breakwaters in Busan Yacht Harbor

  • Dodaran, Asgar Ahadpour;Park, Sang Kil;Kim, Kook Hyun;Shahmirzadi, Mohammad Ebrahim Meshkati;Park, Hong Bum
    • 한국해양공학회지
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    • 제29권1호
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    • pp.62-69
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    • 2015
  • Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.

HadGEM2-AO 기반의 빙상과 빙하에 의한 미래 해수면 변화 전망 (Projection of Future Sea Level Change Based on HadGEM2-AO Due to Ice-sheet and Glaciers)

  • 김영미;구태영;문혜진;최준태;변영화
    • 대기
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    • 제29권4호
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    • pp.367-380
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    • 2019
  • Global warming causes various problems such as the increase of the sea surface temperature, the change of coastlines, ocean acidification and sea level rise. Sea level rise is an especially critical threat to coastal regions where massive population and infrastructure reside. Sea level change is affected by thermal expansion and mass increase. This study projected future sea level changes in the 21st century using the HadGEM2-AO with RCP8.5 scenario. In particular, sea level change due to water mass input from ice-sheets and glaciers melting is studied. Sea level based on surface mass balance of Greenland ice-sheet and Antarctica ice-sheet rose 0.045 m and -0.053 m over the period 1986~2005 to 2081~2100. During the same period, sea level owing to dynamical change on Greenland ice-sheet and Antarctica ice-sheet rose 0.055 m and 0.03 m, respectively. Additionally, glaciers melting results in 0.145 m sea level rise. Although most of the projected sea level changes from HadGEM2-AO are slightly smaller than those from 21 ensemble data of CMIP5, both results are significantly consistent each other within 90% uncertainty range of CMIP5.

안면도 사질 조간대에 서식하는 대형저서동물의 공간분포 및 군집구조 (Spatial Distribution and Community Structure of Macrobenthos on the Sandy Shore of Anmyeondo, Korea)

  • 정윤환;윤건탁;박흥식;마채우
    • Ocean and Polar Research
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    • 제35권1호
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    • pp.27-37
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    • 2013
  • The western coast of Anmyeondo is open toward the Yellow sea and the northern and southern coasts are sandy and have simple coastlines. In this study, we investigated the spatial distribution and community structure of the macrobenthos that inhabit the sandy shore of Anmyeondo. For the study, we chose 8 sites encompassing 44 stations. In total, we have recorded 62 species, and collected 747 inds./$m^2$ on average. Zonation pattern did not appear because the mean grain size and organic contents of the study sites were similar among the macrobenthos. Polychaetes were most frequently recorded, but amphipods appeared in higher mean density. Macrobenthic community is classified into 3 groups largely based on the density difference among the dominant species and the groups were not influenced by environmental factors. The aggregated distribution of macrobenthos did not show a clear regional spatial difference but exhibited classification pattern emphasizing the density difference of the dominant species. The sandy shores of Anmyeondo are relatively more influenced by waves compared to other regions and the sediment moves more due to strong winds, etc. at low tide. We presume that the movement of sediment resulted in a relatively even sedimentary environment and consequently weakened environmental variables that change with the tide level. We concluded that the macrobenthic community does not show the zonation pattern in the sandy shores of Anmyeondo due to such influences.

COASTLINE DETECTION USING COHERENCE MAP OF ERS TANDEM DATA

  • Kim, Myung-Ki;Park, Jeong-Won;Choi, Jung-Hyun;Jung, Hyung-Sup
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.368-371
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    • 2006
  • A coastline is the boundary between land and ocean masses. Knowledge of coastline is essential for autonomous navigation, geographical exploration, coastal erosion monitoring and modelling, water line change, etc. Many methods have been researched to extract coastlines from the synthetic aperture radar (SAR) and optic images. Most methods were based on the intensity contrast between land and sea regions. However, in these methods, a coastline detection task was very difficult because of insufficient intensity contrast and the ambiguity in distinguishing coastline from other object line. In this paper, we propose an efficient method for the delineation of coastline using interferometric coherence values estimated from ERS tandem pair. The proposed method uses the facts that a tandem pair of ERS is acquired from a time interval of an accurate day and that the coherent and incoherent values in coherence map are land and water, respectively. The coherence map was generated from ERS tandem pair, filtered by MAP filter, and divided into land and water by the determination of threshold value that is based on the bimodality of the histogram. Finally, a coastline was detected by delineating the boundary pixels. There was a good visual match between the detected coastline and the manually contoured line. The interferometric coherence map will be helpful to identify land and water regions easily, and can be used to many applications that are related with a coastline.

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무인항공기를 이용한 해안선 변화 추출에 관한 연구 (Method to Extract Coastline Changes Using Unmanned Aerial Vehicle)

  • 이강산;최진무;조창현
    • 대한지리학회지
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    • 제50권5호
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    • pp.473-483
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    • 2015
  • 본 연구에서는 소형 무인항공기를 이용하여 해안 지형을 항공촬영 한 연구결과를 바탕으로 해안선 추출 및 변화량을 분석하였다. 해안지역의 경우 해양-육지간의 지속적인 상호작용으로 변화속도가 매우 빠르고, 연구자의 직접적인 관찰이 제한되는 경우가 많아 원격탐사 자료를 이용한 많은 연구가 이루어져 왔다. 그러나 전통적인 원격탐사 방법은 시공간의 제약, 높은 운용비용 등이 한계점으로 지적되어 왔다. 이에 새로운 원격탐사 플랫폼인 무인항공기를 이용하여 해안선을 추출하였다. 촬영된 영상으로부터 이미지 프로세싱을 통해 해안선을 추출하였고, 조위차에 따른 해안선의 변화를 관찰하였다. 본 연구에서 활용한 소형 무인항공기와 소형 디지털 카메라는 기존 원격탐사 플랫폼과 비교하여 경제성에서 장점이 있다. 최근 무인항공기는 여러 분야에서 다양한 목적으로 연구가 진행되고 있는 바, 지리학 분야에서도 공간정보 구축의 플랫폼으로서 지역연구 등 다양한 활용이 가능할 것으로 판단된다.

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Changes in Biston robustum and Camellia japonica distributions, according to climate change predictions in South Korea

  • Kim, Tae Guen;Han, Yong-Gu;Jeong, Jong Chul;Kim, Youngjin;Kwon, Ohseok;Cho, Youngho
    • Journal of Ecology and Environment
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    • 제38권3호
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    • pp.327-334
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    • 2015
  • We investigated the current and potential spatial distributions and habitable areas of Biston robustum and Camellia japonica in South Korea in order to provide useful data for the conservation of C. japonica and minimize the damage caused by B. robustum. It was predicted that, by 2070, although B. robustum would be widely distributed throughout the Korean Peninsula, except for the western and eastern coastal areas, it would be narrowly distributed along the Sokcho-si and Goseong-gun coastlines in Gangwon Province. C. japonica is currently located along the southern coastline but its critical habitable area is predicted to gradually disappear by 2070. Assessment of the potential distribution probabilities of B. robustum and C. japonica revealed that the area under the curve (AUC) values were 0.995 and 0.991, respectively, which indicate high precision and applicability of the model. Major factors influencing the potential distribution of B. robustum included precipitation of wettest quarter and annual precipitation (BIO16 and BIO12), whereas annual mean temperature and mean temperature of wettest quarter (BIO1 and BIO8) were important variables for explaining C. japonica distribution. Overlapping areas of B. robustum and C. japonica were $11,782km^2$, $5447km^2$, and $870km^2$ for the current, 2050-predicted, and 2070-predicted conditions, respectively, clearly showing a dramatic decrease in area. Although it is predicted that B. robustum would cause continuous damage to C. japonica in the southern part of the Korean Peninsula, such impacts might diminish over time and become negligible in the future.