• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.63-68
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• 2006

Time series of waterline changes during a flood/ebb cycle can be utilized for supplementary data for measuring bottom topography. The waterlines extracted from consecutive images are substituted for depth contours using water level data. The distances between contours are quantified through a rectification image process. This technique is applied to the Keunpoolan beach in the Daeijak Island near Incheon. A camera monitoring technique supported by natural water level changes produces bottom topography with high precision. It is also less time consuming and more economical. The technique also can be utilized effectively to the physical modeling f3r measuring bottom changes in the three dimensional basin.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.2
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• pp.79-87
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• 1993

Executing various constructions and national land planning, it has rised importance how to acquire 3-dimensional geographical information efficiently. In conjunction with this, the concerned parties are interested in the accuracy of GPS positioning and applications. This study suggest the efficiency and possibility to apply geographical information construction by kinematic GPS surveying as comparing kinematic GPS results with triangulation, trilateration and static GPS results. In this study, we try to compare static with kinematic and can determine 3-D positions with difference of 6 mm in distance, 2"/10,000-4"/10,000, 20 cm in latitude, longitude and height at local area. In addition, difference from conventional surveying is about 1"/l0,000-3"/10,000 in horizontal. Therefore it is expected to apply kinematic GPS to make out topographic map and to construct data base associated with GIS.associated with GIS.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.472-472
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• 2021

우리나라는 하천법 제10조, 소하천정비법 제3조에 하천기본계획 수립 또는 하천의 지정 및 변경고시 시 하천구역을 결정하도록 정의되어 있다. 하천구역 설정 시 일반적으로 하천의 제방이 위치하는 부지 및 제방하심측 토지경계를 하천구역으로 지정하고 있으나, 제방계획이 없거나 무제부 구간으로 활용되고 있는 구간의 경우 하천법 제10조 3항에서 5항까지 3가지 항목을 기준으로 계획하폭에 해당하는 토지, 댐·하구둑·홍수조절지·저류지의 계획홍수위 아래에 해당하는 토지경계, 철도·도로 등 제방의 역할을 하는 선형공작물 하심측 토지경계로 구분하고 있다. 하천구역의 경계설정의 경우 불연속적인 특징을 갖는 하천의 횡단측점 자료의 특성상 정확한 평면상의 경계를 파악하기 어렵고, 철도·도로 등 선형공작물 경계를 하천구역으로 설정 시 편입용지의 보상이 상이하고 모호한 기준으로 인해 다량의 민원이 발생하는 실정이다. 본 연구에서는 부산시에 위치한 지방하천 대천천을 대상지로 설정하였으며, 계획홍수위를 기반으로 홍수범람예상도를 작성하여 정밀계획홍수위선을 산출하고 이를 지형자료와 중첩하여 계획홍수위 경계를 추출하였다. 또한 무제부 구간 내 드론촬영을 실시하여 대상지 드론영상 기반 3차원 정밀 지형자료를 구축하고 이를 앞서 산정한 계획홍수위 경계자료와 중첩하여 정밀 하천구역을 설정하였다. 대상지 정밀 하천구역 산정 결과를 기반으로 도심지내 하천과 도시외곽 하천으로 구분하고 다시 도심지내하천은 암거(복개)구간과 개거구간, 도시외곽하천은 유제부와 무제부 구간으로 구분하여 정밀 하천구역 결정기준을 수립하였다. 본 연구를 통해 대천천유역을 대상으로 실시한 무제부 구간 하천구역 결정과정을 기반으로 하천유형별 3차원 하천구역 산정기법을 정립하였다. 향후 해당기법을 실무에 적용하여 하천구역 산정 시 모호한 하천경계부분 또는 토지소유주와 담당부처 간 하천구역 논의 시 기반자료로 활용될 수 있을 것으로 사료되며, 기본계획 수립 시 해당 기법 적용을 통해 보다 정확한 하천구역 경계 수립이 될 수 있을 것으로 기대된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.359-369
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• 2022

In slope stability analysis for landslides, mountains have various slopes and geographical features, and hence it is necessary to estimate stability using rigorous analysis methods. In this study, after the analysis of infiltration behavior through unsaturated layers due to rainfall, the stability of landslide was estimated to account for the variation of pore water pressures. In the analysis of slope stability, a three-dimensional slope analysis was compared with an infinite slope analysis in a case study of terrain in which an actual landslide occurred. In the three-dimensional slope stability analysis, it was found that the location of the failure and the failure area were predicted accurately based on the detailed geological information despite the variation of geographical features.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.1
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• pp.91-107
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• 1995

In this paper, previously proposed mechanisms of generation and maintenance of rip currents are grouped into three broad categories; (1) prismatic topography models, (2) non-prismatic topography models and (3) structural controls by natural and/or constructed features, such as headlands, piers. groins, jetties. etc. The prismatic models can explain the occurrence of a rip current on a planar beach, while non-prismatic model needs undulatory topography inside the surf zone to generate and maintain a rip current. Yet more detailed and thorough studies need to be conducted to include all relevant variables and to clarify the mechanism(s) governing rip current. Next a simple model is presented to predict mean longshore currents behind a longshore bar (or submerged breakwaters) by considering mass transport over the bar and the bar morphology. This hydrodynamic model could be extended to include the sedimentary feedback mechanism.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.152-159
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• 2014

Recently. utilization of remote sensing exploration and cloud computing has been extended to efficient measurement, store, and update of bathymetry map data according to cloud computing technology. In the field of real ocean, water depth measurements and measurement data management, distribution, and display equipment for the development and dissemination have generated a lot of time and cost. To improve these problems, through real-time three-dimensional display system at this location, we can determine the importance of measurement activities, and reduce the time and cost of measurement activities. Data measured from marine probe vessels and remote sensing exploration equipments and other various channels can be handled and managed. In this paper, we propose a realtime three-dimensional display system through the depth measurements from remote sensing exploration. The proposed real-time three-dimensional display system can be effectively applied in the field of measurement of the topographical survey of the land as well as bathymetry of the sea.

• Journal of Korean Society of Disaster and Security
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• v.6 no.3
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• pp.9-17
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• 2013

Geospatial information data came recently in use to build the location-based service in various fields. These data were shown via a 2-D map in the past but now can be viewed as a 3-D map due to the dramatic evolution of IT technology, thus improving efficiency and raising practicality to a greater extent by providing a more realistic visualization of the field. In addition, many previous GIS applications have been provided under desktop environment, limiting access from remote sites and reducing its approachability for less experienced users. The latest trend offers service with web-based environment, providing efficient sharing of data to all users, both unknown and specific internal users. Therefore, real-time information sensors that have been installed on steep slopes are to be integrated with 3-D geospatial information in this study. It is also to be developed with web-based environment to improve usage and access. There are three steps taken to establish this system: firstly, a 3-D GIS database and 3-D terrain with higher resolution aerial photos and DEM (Digital Elevation Model) have been built; secondly, a system architecture was proposed to integrate real-time sensor information data with 3D Web-based GIS; thirdly, the system has been constructed for Gangwon Province as a test bed to verify the applicability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.874-880
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• 2019

This paper introduces a method which can be effectively used for the path planning of UAV in a realistic map which has mountainous terrains, air defense networks and radars based on the Visibility Graph. Existing studies of Visibility Graph have been studied mainly for simple shape obstacles in 2-dimensional environment such as self-driving cars which avoid buildings. However, for UAV, Visibility Graph must be used in 3-dimensional environment for the variance of altitude. This occurs significant elapsed time increase because of the increase of the amount of the visibility of node sets. To solve this problem, this paper decrease the number of nodes which consists the complex terrain environments using convex hull based on Layered Visibility Graph. With convex hull method, this paper confirmed that the elapsed time is decreased about 99.5% compared to the case which has no decrease of the number of nodes.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.255-255
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• 2015

지진해일은 주기가 긴 파랑으로 방파제나 방호구조물에 의한 에너지 감소가 작은 특성이 있다. 또한, 범람구역의 구조물 밀집도 및 지형적 요인에 따라 범람영역, 침수심, 파력 등이 상이하게 나타나므로 유체흐름의 입체적 변화양상을 고려하여야 한다. 본 수리모형실험은 임원항을 대상으로 구조물에 작용하는 지진해일의 파력특성을 3차원수리모형실험을 통해 검토하고, 파력산정계수(${\alpha}$)를 제시한다. 3차원 수리모형실험은 1983년 동해 중부 지진해일 발생 시 국내에서 가장 큰 피해를 입은 임원항을 대상으로 배후부지의 구조물과 인근 해안의 지형을 1/100으로 재현하여 실험에 임하였다. 입사파랑은 고립파(solitary wave)로 재현하였으며, 천수(shoaling)에 의한 파고변화를 측정하고 그에 따른 배후부지의 침수심, 구조물에 작용하는 파력을 측정하였다. 분석된 파력 산정계수(${\alpha}$)는 임원항 인근 해역 및 배후부지의 방재대책 수립을 위한 기초자료로 활용될 것으로 판단된다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.569-576
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• 2011

Recently the establishment of high accuracy 3D spatial information has been largely stimulated according to the increase in need of such 3D spatial information. In the fields of constructions and civil works, studies on increasing the productivity in these fields through converging them with other fields using the established 3D spatial information have been conducted. In such a tendency, BIM (Building Information Modeling) technologies have been rapidly applied to the fields of constructions and civil works. In particular, in the fields of constructions and civil works that represent a life span of plan-design-construction-maintenance, some BIM application methods and plans for the characteristics in each step have been proposed. Thus, the objective of this study is to simulate a project that is reasonable and can be optimized in connection with 3D spatial information and BIM technologies escaped from the conventional civil construction process that is based on empirical, statistical DB, and 2D information. For achieving this objective, 3D terrain data for the subject area engaged in this study using aerial photographs and airborne LiDAR was established. Also, a counter plan for the issues, which cannot be solved in the conventional methods for managing civil work projects, is applied through implementing bridge-based civil structure BIM by combining them with objective information.