• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.81-88
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• 2012

This present research was carried out by dividing two parts; field surveying and data processing, in order to analyze changed patterns of a shoreline. Firstly, the shoreline information measured by the precise GPS positioning during long duration was collected. Secondly, the algorithm for detecting an auto boundary with regards to the changed shoreline with multi-image data was developed. Then, a comparative research was conducted. Haeundae beach which is one of the most famous ones in Korea was selected as a test site. RTK-GPS surveying had been performed overall eight times from September 2005 to September 2009. The filed test by aerial Lidar was conducted twice on December 2006 and March 2009 respectively. As a result estimated from both sensors, there is a slight difference. The average length of shoreline analyzed by RTK-GPS is approximately 1,364.6 m, while one from aerial Lidar is about 1,402.5 m. In this investigation, the specific algorithm for detecting the shoreline detection was developed by Visual C++ MFC (Microsoft Foundation Class). The analysis result estimated by aerial photo and satellite image was 1,391.0 m. The level of reliability was 98.1% for auto boundary detection when it compared with real surveying data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.2
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• pp.150-156
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• 1994

Shoreline change due to the littoral drift in Suyeong bay, especially the Gwanganri and Haeundae beaches, was investigated. Average monthly frequency. speed. and direction of winds blowing from between east and south for the last 15 years were analysed, and offshore significant waves were hindcasted using the JONSWAP model. Wave refractions, shoaling, and breaking weir also investigated for the calculation of littoral drift. At the Gwanganri beach major longshore transport of sands occurs from the southwest to the northeast and the shoreline seems to advance in the northeast while it recedes in the southwest. At the Haeundae beach the sands mainly move from the east to the west and the shoreline retreats in the east and advances in the west.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.1-10
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• 2007

The tendency of erosion and accretion of the coast has occurred by the wanton development of a shore so that establishing the plans of nature preservation and development according to shoreline change is in demand. In this study, six DGPS positioning are executed in the periodic interval of about 2 months to choose coastal area of Gangnung, Gangwon-do and the observation data which is post-processed about 50cm accuracies on the Gangnung regular service is compared with digital map in 1998 and digital chart in 2006. Comparing DGPS values with shoreline of digital map, we know that erosion has occurred locally around training dike placed in Gangmun harbor and in southern Namhangjin, many accretions has happened near the breakwater of Namhangjin region and partial accretion is occurring in the other area. Therefore DGPS which is an acquisition method suitable for GIS data input is in use to collect the horizontal data and it could be used effectively to measure the shoreline change of time series through the long-term continuous observation by the coastal development.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.191-198
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• 2007

According to the survey data during the Japanese Occupation Period, the length of South Korea's coastline is about 11,542km, including the coastlines of mainland and islands. To accurately revise/renew this coastline data through site survey, it will cost great money and time. Also, various development projects such as reclamation works on public waters, constructions of ports/harbors, etc. This paper used aerial photographs, satellite image data and GPS survey data with certain intervals to monitor the change in coastal areas of Songieong, Haeundae, Kwanganri, Songdo and Dadaepo. The local area subjected for this research was limited to areas near Busan. The specific contents of this research include. Launching qualitative/time series analyses on the change of coastal areas using aerial photographs, satellite image data and RTK-GPS surveys.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.169-180
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• 2019

Shorelines should be extracted with consistency because they are the reference for determining the shape of a country. Even in the same area, inconsistent minimum vertex intervals cause inconsistencies in the coastline length, making it difficult to acquire reliable primary data for national policy decisions. As the shoreline length cannot be calculated consistently for shorelines produced by determining the arbitrary distance between points below 1m, a methodology to calculate consistent shoreline length using the minimum vertex interval is proposed herein. To compare our results with the shoreline length published by KHOA(Korea Hydrographic and Oceanographic Agency) and analyze the change in shoreline length according to the minimum vertex interval, target sites was selected and the grid overlap of the shoreline was determined. Based on the comparison results, minimum grid sizes and the minimum vertex interval can be determined by deriving a polynomial function that estimates minimum grid sizes for determining consistent shoreline lengths. By comparing public shoreline lengths with generalized shoreline lengths using various grid sizes and by analyzing the characteristics of the shoreline according to vertex intervals, the minimum vertex intervals required to achieve consistent shoreline lengths could be estimated. We suggest that the minimum vertex interval methodology by quantitative evaluation of the determined grid size may be useful in calculating consistent shoreline lengths. The proposed method by minimum vertex interval determination can help derive consistent shoreline lengths and increase the reliability of national shorelines.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.3
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• pp.187-193
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• 2022

In the Yeongdong region of Gangwon-do, coastal areas are important resources in terms of cultural, social and economic aspects. However, the coast of Gangwon-do is experiencing severe erosion, and it is concerned that its adverse effects will gradually increase. In this study, coastline changes of Yangyang and Gangneung in Gangwon-do were tracked and analyzed over a long period of time. In order to build time series image data, aerial photos from the 1940s to the present were mainly used, and data from CORONA satellite, which operated from the 1960s to the early 1970s, were collected and used together. Using 51cm resolution ortho image and 2m resolution Digital Elevation Model(DEM) as reference, ground control points were selected to perform geometric correction on the aerial photos and CORONA images. Subsequently, Canny edge detector applied to these images to extract the coastlines. As a result of analyzing the extracted and vectorized coastlines by overlaying them in chronological order, erosion and deposition occurring around the artificial structures and on the nearby beaches were observed. In this study, the effect of seasonal variation, tide, and various coastal management including the beach filling were not considered. Because coastal erosion is greatly affected by geographic factors, each local government must find its own solution. Continuous research and local data accumulation are required.

• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.167-173
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• 2004

The erosion(or sediment) reaches very serious level due to the aftermath by the imprudent reclamation on the coast. Continuous studies for long on coastline erosion may be warranted and possible countermeasures proposed because the change of the coastline has been progressed slowly for a long period of time in a wide area. Many experts anticipate that the global sea level's average increase by 19-35 cm due to global warming may certainly have an effect on the coastal erosion throughout the world. Thus, a more rigorous study on the causes of changing coastlines is particularly proposed to find ways to counteract any possible threats against coastal environments. In this study, Ortho aerial photo and hydrographic survey datum were utilized to quantitatively analyze coastal erosion and sediment patterns. This paper also seeks to prove that a parcel under the sea occurred due to relatively significant changes to the coastline. We created Ortho aerial photo using aerial photos taken each decade ('81, '93, '00), overlaid them onto a cadastral registration map, and calculated each amount of erosion and sediment while accounting for the tide level and without considering it. As the result of this study, we could propose that the methods of Ortho aerial photo and the marine observation datum were the effective ways of change detection in erosion, sediment, and artificial reclamation of the coastline for a long time.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.574-583
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• 2013

The coastal area, which is managed by local governments, geographically, culturally and economically has been transformed into more influential space. In recent years, new type of fusion researches about coastal areas that have economic, cultural and engineering aspects, have been conducted. In this study, the multiple observations information was used to analyze change of Ilsan beach shoreline which is located in Dong-gu, Ulsan, Korea. For the shoreline analysis, we used VRS-RTK(Virtual Reference System by Real-Time Kinematic) GPS survey, aerial photograph, terrestrial LiDAR survey and fixed reference station survey. Specially fixed reference station method was suggested for shoreline observation and maintenance. In the case of Ilsan beach shoreline, according to the result of multiple observations information, coastline erosion(6~12m) appeared in medium and lower part and sedimentation(3~14m) in the upper part of coastline.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.584-596
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• 2005

Morphology, surface sediments, sedimentation rates and sea-cliff erosion have been monitored, for one year to investigate the shoreline changes and tidal beach characteristics in Cheonsu Bay along the west coast of Korea. The seacliff of the bay consists of intensively weathered sedimentary rocks and soft soil, showing an erosion range of $-58.9\~73.3cm/yr$ by a weak wave forcing. Active sea-cliff erosions are recognized by peculiar geomorphic features, including saw teeth-shaped coastline, gravels, relict weathered basement-rock and 'Island Stack' exposed on the high-tide beach surface. The beach sediments show low compositional maturity at the south and north headlands and gradually high towards the central part. This observation seems to be caused by the fact that beach sediments are to originate from the both headlands in the study area and then transported by long-shore current associated with a wave action.

• Journal of the Korean earth science society
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• v.22 no.4
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• pp.317-326
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• 2001

The coastline of semi-enclosed Hampyung Bay, southwestern coast of Korea, consists largely of erosional sea-cliffs characterized by steep face slope, low in height (less than 3m), and composition of soft reddish soil. Recession rates of the sea-cliffs in the Haeuri coast of Hampyung Bay, which were Quantified by photogrammetry using single aerial photographs taken 1976 and 1990, respectively, were approximately 1${\sim}2m/yr. This value is in good agreement with the field measurement conducted by Chang et al. (1999). Subsequently, the photogrammetry seems to be a very useful method to measure easily long-term coastline change. This severe erosion of sea-cliff in the semi-enclosed bay environment, furthemore, is probably due to combined effects of typhoon or/and storm surges and weak resistance of soil cliff itself.