• Korean Journal of Remote Sensing
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• v.34 no.3
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• pp.439-450
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• 2018

The lineament is a linear or curved terrain element to discriminate adjacent geological structures in each other. It has been widely used for analysis of geology, mineral exploration, natural disasters, and earthquake, etc. In the past, the lineament has been extracted using cartographic map or field survey. However, it is possible to extract more efficiently the lineament for a very wide area thanks to development of remote sensing technique. Remotely sensed observation by aircraft, satellite, or digital elevation model (DEM) has been used for visual recognition for manual lineament extraction. Automatic approaches using computer science have been proposed to extract lineament more objectively. In this study, we evaluate the characteristics of lineament which is automatically extracted with respect to difference of spatial resolution of DEM. We utilized two types of DEM: one is Shuttle Radar Topography Mission (SRTM) with spatial resolution of about 90 m (3 arc sec), and the other is the latest world DEM of TerraSAR-X add-on for Global DEM with 12 m spatial resolution. In addition, a global DEM was resampled to produce a DEM with a spatial resolution of 30 m (1 arc sec). The shaded relief map was constructed considering various sun elevation and solar azimuth angle. In order to extract lineament automatically, we used the LINE module in PCI Geomatica software. We found that predominant direction of the extracted lineament is about $N15-25^{\circ}E$ (NNE), regardless of spatial resolution of DEM. However, more fine and detailed lineament were extracted using higher spatial resolution of DEM. The result shows that the lineament density is proportional to the spatial resolution of DEM. Thus, the DEM with appropriate spatial resolution should be selected according to the purpose of the study.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.383-386
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• 2003

이 연구는 주변국의 국가지도제작기관을 분석하고, 측량 및 지도제작을 위한 수치제작 체계 즉, 수치자료기반을 제작하기 위한 체계를 분석하고자 하는 것

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.115-120
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• 2003

일반적으로 광학위성은 궤도가 부정확하여 지상기준점(GCP)을 이용하여 궤도를 보정하는 작업을 수행한 후 수치 표고모형 자료(DEM)를 추출한다. 지상기준점은 실제 측량이나 지형도로부터 얻게 되지만, 이러한 작업이 불가능한 경우에는 광학영상으로부터 수치 표고 모형 자료를 추출할 수 없다. 본 연구에서는 수-수십 cm의 위성 궤도 정확도를 지니는 ESA ERS영상과 약 1Km의 해상도를 지니는 GTOPO-30 DEM을 이용하여 지상기준점을 추출 방법에 대해 연구하였다. 연구지역인 대전 주변에 대하여 지상기준점을 추출한 결과 경도 -0.348초, 위도 0.293초의 오차를 나타내었다. 또한 추출된 지상기준점을 이용하여 한 쌍의 SPOT 위성영상으로부터 DEM을 추출이 가능하였으며, 레이더 interferometry 기술을 이용한 지형고도 추출 및 변화 탐지에도 활용될 수 있음을 확인하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.91-100
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• 1999

To extract value-added products from satellite images for the benefit of science and human life, the Satellite Technology Research Center at Korea Advanced Institute of Science and Technology has developed an integrated software 'Valadd-Pro'. In this paper, the 'Valadd-Pro' software is briefly introduced and its main components such as geometric correction, ortho correction and digital elevation model extraction are described. The performances of the 'Valadd-Pro' was assessed on $60km{\times}60km$ SPOT panchromatic images using ground control points from GPS measurements. Also, the height accuracy was measured by comparing our results with the $DTEDs^3$ produced by USGS and the DEM generated from the digitized countours of maps produced by the National Geographic Institute. In geometric correction, the 'Valadd-Pro' software needed fewer ground control points than a commercial software 'P' for the satisfactory results. In ortho correction, the 'Valadd-Pro' software show the similar performance to a commercial software 'P'. In digital elevation model extraction, the 'Valadd-Pro' software is two times more accurate and four times faster than a commercial software 'P'.

• Spatial Information Research
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• v.10 no.3
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• pp.439-453
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• 2002

Researches using DEM are actively progressed in field of water resource, and especially the extraction of watershed and stream based on topographic and hydrologic analysis, is widely used in GIS analysis recently. However, because it is extracted that watershed which is type of sliver polygon and stream which is type of straight line in low topographic region, they're not efficient for application. This study determined buffer zone from stream and tried smooth elevation change to buffer zone in order to efficiently extract abnormal watershed and stream being occurred in low topographic region. Especially, we applied equal-distance assignment model using Voronoi Diagram to determine smooth elevation change. Also, we extracted watershed and stream using stream recognition DEM and origional DEM, and evaluated the efficiency of research through comparing the shape of watershed and stream in low topographic region.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.151-165
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• 2008

Ground slope and aspect are important parameters for physical deterministic water balance models like BROOK90 or hydrological models which attempt to calculate evapotranspiration, snowmelt, and net radiation. This study constructs a Digital Elevation Model(DEM) and examines how DEM resolution can change the average ground slope and aspect of a river basin and attempts to evaluate the effects on simulation results of BROOK90, a physical deterministic water balance model. The study area is Byungcheon river basin in Korea. DEM has been constructed using a 1:25,000 digital map with the methods of TIN and Topo To Raster. The total of 20 DEMs with 10m~100m resolution have been constructed, with a 10m interval. It was found that the higher the DEM resolution, the steeper the average ground slope value of the Byungcheon river basin. In turn, the direct solar radiation of a hilly area in the model increased the evapotranspiration and reduced the stream runoff in the Byungcheon river basin. On the other hand, a lower DEM resolution tends to move the average aspect from southeast to south in the Byungcheon river basin. Accordingly, it was found that stream runoff was reduced and evapotranspiration increased.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.291-294
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• 2004

최근 들어 위성영상의 사용성 증대와 더불어 고정밀한 공간지리정보의 획득에 대한 관심이 증대되고 있으며, 모델링의 정확도 수준은 수치표고모형, 정사영상 등에 영향을 미치므로 고정밀 모델링 기법을 수행하여야함. 또한 비접근 지역의 경우 많은 기준점을 획득하기 어려우므로 최소 기준점 즉, 2점 의 GPS관측성과와 수치지도를 이용하여 궤도모델링을 수행한 후 모델링(Bundle Adj.)을 수행

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.1
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• pp.27-36
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• 2003

Generally, the latest acquisition method of geo-spatial informations in urban area is executed by generation of digital elevation model (DEM) and digital ortho image by digital photogrammetry method which is used large scale photo image. However, the biggest problem of this method is coarse accuracy of DEM which is automatically generated by digital photogrammetry workstation system. The coarse accuracy of DEM caused geo-spatial information in urban area to reduce of accuracy. Therefore, this study is purposed to increase of DEM accuracy which is applied to method terrain classification in urban area. As the results of this study, the proposed method of this study which is increased to accuracy of DEM by classification of terrain is better than accuracy of DEM which is automatically generated by digital photogrammetry workstaion system. And, the edge detection method which is proposed by this study is established to capability of 3D digital mapping in urban area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.4
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• pp.359-365
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• 2006

Recently generated natural disaster of rainfall is transformed into nationwide generate form from a specific region of generated form that damages are steadily growing. such natural disaster lead to much influence such as socioeconomic, financial, physical and casualties etc, therefore model collection can be a step required establishment of systematically management foundation and offer of systematic solved plan. this study proposed to analyze and arrange pattern of disaster and systems designed plan and establishment further scientific, prompt service of disaster. with GIS technique for decision-making offer the necessary preliminary data. also, each city have orthophoto and digital elevation model that analyze real topography and situation. with establish management system in order to carry out appropriate service of disaster management and establish realistic management system. system had established that OpenGL make three dimensional illustrate scale image data and digital elevation model therefore a module of section analysis developed way to illustrate and to analyze topography and longitudinal section in screen.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.545-553
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• 2009

Digital Elevation Models (DEM) is widely used in establishing the topographic profile in nation spatial information. Aerial Light Detection And Ranging (LiDAR) system is one of the well-known means to produce DEM. The system has fast data acquisition procedures and less weather-dependent restrictions compared to photogrammetric approaches. In this regards, LiDAR has been widely utilized and accepted in the process of nation spatial information generation due to its sufficient positional accuracy. However, the investigation of the accuracy of aerial LiDAR data over the area of forestation with various kinds of vegetations has been barely implemented in Korea. Hence, this research focuses on the investigation of the accuracy of aerial LiDAR data over the area of forestation and the evaluation of the acquired accuracy according to the characteristics of the vegetations. The study areas include land with shrubs and its adjacent forest area with mixed tree species. The spots for the investigation have been selected to be well-distributed over the whole study areas and their coordinates are surveyed by Global Positioning Systems (GPS). Then, the surveyed information and aerial LiDAR data have been compared with each other and the result accuracy has been evaluated. Conclusively, it is recommended that LiDAR data collection to be conducted after defoliation period, especially over the areas with broadleaf trees due to the possibility of significant outliers.