• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.237-250
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• 2023

Orthophotos and DEMs were generated by UAV-based aerial photogrammetry and an attempt was made to apply them to detailed investigations for the production of flood traces. The cultivated area located in Goa-eup, Gumi, where the embankment collapsed and inundated inundation occurred due to the impact of 6th Typhoon Sanba in 2012, was selected as rhe target area. To obtain optimal accuracy of UAV photogrammetry performance, the UAV images were taken under the optimal placement of 19 GCPs and then point cloud, DEM, and orthoimages were generated through image processing using Pix4Dmapper software. After applying CloudCompare's CSF Filtering to separate the point cloud into ground elements and non-ground elements, a finally corrected DEM was created using only non-ground elements in GRASS GIS software. The flood level and flood depth data extracted from the final generated DEM were compared and presented with the flood level and flood depth data from existing data as of 2012 provided through the public data portal site of the Korea Land and Geospatial Informatix Corporation(LX).

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.925-936
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• 2003

The objective of this study is to suggest new drawing methods of isochrones using GIS. For this purpose the Unit Hydrograph (UH) of studied watershed for instantaneous rainfall suggested by Clark have been determined by routing the time-area curve through a single linear reservoir. To evaluate constructing methods of isochrones three methods has been examined; Channel Profile and Clark-kict method; Laurenson method; Average velocity method of S.C.S. Also, these methods have been recomposed by GIS in this study. To apply first method, spatial modeling, the vector based on the stream network and Route_System measuring a distance between points has been used. A raster based on the flow direction grid from burn DEM and the slope grid from original DEM has been applied for the second method. The third method has been applied by a raster based on the landuse grid and a velocity function expressed by slope. Results by these three methods have been evaluated with observed hydrograph, and the method using average velocity method of S.C.S shows more reasonable results comparatively.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.167-172
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• 2002

본 연구는 GPS를 이용하여 위성 영상의 입체 해석으로 산출된 SPOT영상의 기준점 및 수치 표고 모형의 평가에 목적이 있다. 이를 위해 삼각점 및 상시관측소를 고정으로 한 GPS 해석을 수행하였으며 정지측량과 이동측량의 정확도를 비교함으로써 위성 영상의 기준점과 수치 표고 모형의 평가를 위한 측량 방법을 분석하였다. 연구 결과, SPOT영상의 해상력을 고려할 때, 이동 GPS측량기법으로도 수치 표고 모형의 정확도 평가가 가능하였으며, 기준점 좌표 산출에 있어서 고정점에 삼각점 대신 상시관측점들을 사용함으로써 경제적인 GPS 측량을 꾀할 수 있었다.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.54-63
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• 2010

The intensive rainfall over 455 mm occurred between on 9 to 14 July 2009 triggered debris flows around the mountain area in Jecheon County. We mapped the debris flow area and estimated the debris flow volume using a high resolution digital elevation model (DEM) generated respectively from terrestrial LiDAR (Light Detection And Ranging) and topographic maps. For the LiDAR measurement, the terrestrial laser scanning system RIEGL LMS-Z390i which is equipped with GPS system and high-resolution digital camera were used. After the clipping and filtering, the point data generated by LiDAR scanning were overlapped with digital map and produced DEM after debris flow. The comparison between digital map and LiDAR scanning result showed the erosion and deposition volumes of about $17,586m^3$ and $7,520m^3$, respectively. The LiDAR data allowed comprehensive investigation of the morphological features present along the sliding surface and in the deposit areas.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.232-249
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• 1998

The first Korean remote sensing satellite, Korea Multi-Purpose Satellite (KOMPSAT-1), is going to be launched in 1999. This will carry a 7m resolution Electro-Optical Camera (EOC) for earth observation. The primary mission of the KOMPSAT-1 is to acquire stereo imagery over the Korean peninsular for the generation of 1:25,000 scale cartographic maps. For this mission, research is being carried out to assess the possibilities of automated or semi-automated mapping of EOC data and to develop, if necessary, such enabling tools. This paper discusses the issue of automated digital elevation model (DEM) generation from EOC data and identifies some important aspects in developing a DEM generation system from EOC data. This paper also presents the current status of the development work for such a system. The development work will be described in three pares of sensor modelling, stereo matching and DEM interpolation. The performance of the system is shown with a SPOT stereo pair. A DEM generated from commercial software is also presented for comparison. The proposed system seems to generate promising results.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.23-33
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• 2005

Hydrologic-topographical parameters were extracted using GIS. The use of GIS is more effective and exact than the execution by person. And the purpose of this paper is to extract more efficient size of grid for DEM analysis by applying GIS technology. As a result, when the grid size is less than $100m{\times}100m$ the trend of extracted parameters is similar but when the grid size is over $100m{\times}100m$ the trend of extraction parameters is dispersive. Therefore, it is appropriate to extract hydrologic-topographical parameters the grid size of $100m{\times}100m$ in DEM analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.286-286
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• 2017

자연재난은 전 세계적으로 인명 및 재산피해를 야기하고, 근래에는 기후변화로 인한 국지성 집중호우와 태풍의 발생빈도가 증가하고 있으며, 국토면적의 64%가 산지로 이루어져 있는 우리나라에서는 산지재해의 위험 가능성이 매우 높다. 이 중 토석류 재해는 붕괴된 토사가 물과 함께 섞여 높은 농도로 하류를 향해 이동하기 때문에 그 발생시점과 발생위치를 예측하기 어렵고, 토석류의 이동경로와 퇴적부 지점에 위치하고 있는 시설물 및 인명에 매우 큰 피해를 입히는 자연재해 중 하나이다. 본 연구대상지역은 충북제천시 봉양읍 공전리 일대에 위치하고 있으며, 2009년 7월 시간최대강우량 64mm, 누적강우량 455m의 집중호우로 인해 토석류가 발생하였고, 하류부에 위치한 민가와 비닐하우스, 농경지등에 피해가 발생하였다. 이에 본 연구에서는 지상LiDAR를 활용하여 고정밀도 DEM(Digital Elevation Model)을 구축하였다. 그리고 토석류 수치모형 중 미연방재난관리청(FEMA)에서 토석류 해석에 권장하고 있는 프로그램 FLO-2D모형과 일본에서 개발된 Kanako-2D모형을 적용하여 실측된 토석류 확산범위와 유출토사량을 수치모형의 결과와 비교분석하여 모형의 적용성을 검토하였다.

• Annual Conference of KIPS
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• 2012.11a
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• pp.516-518
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• 2012

일반적으로 표적에 대한 탐지는 감시장비의 성능과 지형지물의 차폐 여부가 가장 큰 영향을 준다. 본 연구는 SRTM DSM (Digital Surface Model)과 국방지형정보단 DEM (Digital Elevation Model) 그리고 여기에 수목고를 고려한 DCM (Digital Canopy Model)고도를 기반으로 탐지확률 실험을 하였다. 실험결과 DCM과 DEM 기반의 탐지확률 결과가 가장 유사성이 높았고, SRTM과 DEM 기반의 탐지 확률은 차이가 나는 것으로 확인하였다. 따라서 SRTM이 이론적으로 DSM으로 고려되지만, 향후 추가적인 연구를 통해 이에 대한 분석이 더 필요할 것으로 사료된다.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.67-75
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• 2002

Recently, GIS tend to be studied in water resoruces field. In hydrology analysis, GIS propose way that can develop subjective element of designer objectively. The development project is conducting disaster effect estimation to breed disaster, and cope these disaster beforehand provoking soil erosion and food recently. In this study, receive value of LS factor through DEM data at volume of soil erosion computation by disaster effect estimation and whether it are some relation effect of gradient and change of soil erosion by grid size did comparative analysis. As a result, according as grid size great, gradient became slow and could know that error value of gradient great according as storing scale of digital topographical map grows.

• Journal of the Korean Geophysical Society
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• v.9 no.2
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• pp.87-97
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• 2006

LIDAR(Light Detection and Ranging) is a new technology for obtaining DEM(Digital Elevation Model)ewith high density and high point acuracy. As LIDAR emerged, DEM could be developed in the earthsurface more efficiently and more economically, compared to the conventional aerial photogrametry.In this study, a digital camera is simultaneously used in combined LIDAR surveying, and acquired digitial image and DEM produce digital orthoimage. In this process, methods of combining sensor andorthoimage, GCPs determined by GPS surveying are used. Two digital orthoimage are produced; onewith a few GCP and the other without them. The produced maps can be used to corect or revised1:1,000 or 1:5,000 scale maps acordingly.