• 융복합기술연구소 논문집
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• 제12권1호
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• pp.1-5
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• 2022

This paper describes an algorithm for generating a terrain using a noise function and a height map as one of the procedural terrain generation methods. The polygon mesh data structure to represent the generated terrain concisely and render it is also described. The Perlin noise function is used as the noise technique for terrain mesh, and the height data of the terrain is generated by combining the four noise waves. In addition, the terrain height information can be also obtained from actual image data taken from the satellite. The algorithm presented in this paper generates the geometry part of the polygon topography from the height data obtained, and generated a material for texture mapping with two textures, that is, a diffuse texture and a normal texture. The validity of the terrain method proposed in this paper is verified through application examples, and its possibility can be confirmed through performance verification.

• 한국항행학회논문지
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• 제28권1호
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• pp.155-158
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• 2024

Multipath, a major error source in urban GNSS positioning (global navigation satellite system), pose a challenge due to its site-dependent nature, varying with the user's signal reception environment. In our previous study, we introduced a technique generating GNSS multipath map in urban canyon. However, due to uncertainty in initial GNSS positions, applying multipath maps required generating multiple candidate positions. In this study, we present an efficient method for applying multipath maps by projecting the multipath correction in position domain. This approach effectively applies multipath maps, addressing the challenges posed by urban user position uncertainties.

• 한국측량학회지
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• 제35권4호
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• pp.241-248
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• 2017

GCPs (Ground Control Points) are needed to correct the DEM (Digital Elevation Model) produced from high-resolution satellite images and the RPC (Rational Polynomial Coefficient). It is difficult to acquire the GCPs through field surveys such as GPS surveys and to read the image coordinates corresponding to the GCPs. In addition, GCPs cannot cover the entire image of the test site, and the RPC correction results may be influenced by the arrangement and distribution of the GCPs in the image. Therefore, a new method for the RPC correction is needed. In this study, an LHD (Least-squares Height Difference) DEM matching method was applied using previous DEMs: SRTM DEM, digital map DEM, and corrected IKONOS DEM. This was carried out to correct the DEM produced from KOMPSAT-3 satellite images and the provided RPC without GCPs. The IKONOS DEM had the highest accuracy, and the height accuracy was about ${\pm}3m$ RMSE in a mountainous area and about ${\pm}2m$ RMSE in an area with only low heights.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.349-354
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• 1999

Electro-Optical Camera (EOC) is the main payload of the KOMPSAT-1 satellite to perform the mission of cartography that builds up a digital map of Korean territory including a digital terrain elevation map. This paper discusses the issues of the digital image simulation of EOC for the generation of EOC simulated scene as taken by EOC at 685km altitude on orbit. For the purpose, simulation work has been performed with the sensor models of EOC and the satellite platform motions models through image chain analysis from the illumination source (Sun) to a simulated image output in digital number. MODTRAN fur radiance calculation, MTF models of optics, detector and motions of EOC for system point spread function (PSF), and signal chain equations for digital number output are described. Several noise models of EOC are also considered. The final output is the EOC simulated image in digital number. The simulation technique can be used in several phase of a spaceborne electro-optical system development project, feasibility study phase, design, manufacturing, test phases, ground image processing phases, and so on.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2003년도 공동 춘계학술대회 논문집
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• pp.65-70
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• 2003

The weight-of-evidence model one of the Bayesian probability model was applied to the task of evaluating landslide susceptibility using GIS. Using the location of the landslides and spatial database such as topography, soil, forest, geology, land use and lineament, the weight-of-evidence model was applied to calculate each factor's rating at Boun area in Korea where suffered substantial landslide damage fellowing heavy rain in 1998, The factors are slope, aspect and curvature from the topographic database, soil texture, soil material, soil drainage, soil effective thickness, and topographic type from the soil database, forest type, timber diameter, timber age and forest density from the forest map, lithology from the geological database, land use from Landsat TM satellite image and lineament from IRS satellite image. Tests of conditional independence were performed for the selection of the factors, allowing the 43 combinations of factors to be analyzed. For the analysis, the contrast value, W$\^$＋/and W$\^$-/, as each factor's rating, were overlaid to map laudslide susceptibility. The results of the analysis were validated using the observed landslide locations, and among the combinations, the combination of slope, curvature, topographic, timber diameter, geology and lineament show the best results. The results can be used for hazard prevention and planning land use and construction

• 환경영향평가
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• 제11권4호
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• pp.289-309
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• 2002

Solutions of many landscape problems depend on area-wide assessment and interpretation of spatial and physical characteristics over the study area. The authors argue that the public awareness for an area-wide urban landscape appears to be very low due to limited chance to the information. Acknowledging these constraints, an operational, user-friendly information system has been developed by combining internet technology with GIS. In particular, integration among satellite data and digital maps takes advantage of each component, and enables the landscape structure to be visualized, interacted with and deployed all on the Web. The 1m resolution IKONOS data realistically identified the major type of landscape by large scale spatial precision while TM data revealed successfully the major parameters that influence an area-wide spatial structure in the study area. This system would play a crucial role in improving the public awareness for area-wide landscape information if it is operationally introduced into the Government since the highly user-friendly interface based on image maps provides a completely new means for disseminating information for area-wide landscape in a visual and interactive manner to the general public.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.275-279
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• 2004

This study was done to detect the topographic and terrain change of the vicinity of the west coast. To make the basic map of the change in topology and terrain, the mosaic images were made using the images from the satellite, which were given the geometric correction based on the GCP (Ground Control Point) and DEM (Digital Elenation Model) data. The accuracy of the images was examined by .empaling them with CCP through 1:25,000's digital map. After that, among the resultant images of the 1970s and 2000s, those of Sihwa, Hwaong and Ansan, the lands reclaimed by drainage were compared to observe the change in the area. From this study, the accuracy of the images of the west coast from satellite could be acquired and the change of the topology and terrain was detected effectively. From the results, it was known that, in case of the land the topological change was not so big due to the development in the reclaimed land or the bare land. In Sihwa, the size of the land was increased 180 $\textrm{km}^2$ and that of the seashore was decreased 110 km. in Hwaong the size was increased 50 $\textrm{km}^2$ and in Ansan the city space was increased 71 $\textrm{km}^2$ due to the formation of the industrial complex.

• 대한지리학회지
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• 제9권
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• pp.67-75
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• 1974

본 연구는 원격탐사 기법을 이용하여 북한 지역을 포함한 한반도 전지역을 대상으로 식생활력도(vegetation activity)의 시계열적 변화를 모니터링하고, 식생지수의 연중변화 특성을 이용하여 한반도의 식생 분포도를 작성하는데 그 목적이 있다. 1997년 4월부터 11월까지 8개월 동안 NOAA-14 위성에서 수신된 AVHRR 자료를 수집하여 정규 식생지수(Nomalized Difference Vegetation Index)를 구하고 이들을 MVC(Maximum Value Composite) 방법으로 조합하여 월별 NDVI 합성도를 작성하여 식생활력도의 시계열 변화를 고찰하였다. 또한 식물의 생장시기인 5월부터 10월까지의 NDVI를 무감독 분류하여 한반도의 식생분포 유형을 도시.나대지가 4.49%, 초지 4.49%, 경작지 27.54%, 활엽수림 25.61%, 침엽수림 38.22%로 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1424-1426
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• 2003

It will be a real good news for the people who were lost their hometown by the construction of a large dam to be restored to the former state. Focused on Cheung-Pyung around where most part were flooded by the Chungju large Dam founded in early 1980s, we used Remote Sensing Technique in this study in order to restore topographical features before the flood with 3 dimensional effects. We gathered comparatively good satellite photos and remotely sensed digital images, then we made a new color image from these and the topographical map which had been made before the flood. This task was putting together two kinds of different timed images. And then, we generated DEM including the outskirts of that area as harmonizing current contour lines with the map. That could be a perfect 3D image of Cheung-Pyung around before when it had been flood by making perspective images from all directions, north, south, east and west, for showing there in three dimensions. Also, flying simulation we made for close visiting can bring us to experience their real space at that time.

• 한국지리정보학회지
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• 제10권3호
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• pp.1-12
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• 2007

본 연구는 수문 및 수리학적 모형을 이용하여 유역내 하천의 월류에 의한 침수구역을 분석하고, SAR 위성영상을 이용하여 내수배제 불량에 의한 제내지 침수구역을 추출한 후 이를 현지조사를 바탕으로 제작된 침수실적도와 비교하여 SAR 위성영상 자료의 활용성을 검토하는 것을 목적으로 하였다. 연구지역은 삽교천 국가하천 구간이며 홍수사상은 1999년 8월 2일~5일 기간에 발생한 홍수를 대상으로 하였다. 연구방법은 HEC-RAS의 홍수사상을 적용하여 홍수위를 분석하였으며 분석된 홍수위 자료를 WMS에서 TIN자료와 분석하여 제내지 침수구역을 추출하고 기존 WAMIS의 침수실적도와 비교하였다. SAR 영상에 의한 침수구역 추출은 침수시기인 1999년 8월 4일의 영상과 침수 후 영상인 2002년 9월 8일의 영상을 칼라합성하여 추출하였으며 이와 같이 추출된 침수구역을 WAMIS의 침수실적도와 비교하였다. 연구결과 수리학적 모형에 의한 침수구역 추출은 외수범람에 의한 침수구역을 추출하는 데는 이용이 가능하나 내수배제 불량에 대한 침수구역 추출에는 한계가 있었다. SAR 위성영상에 의한 침수구역 추출 방법은 수리학적 모형에서 나타난 내수배제 불량에 의한 침수구역 산정에 대한 한계를 보완할 수 있으나 첨두유출 발생시점의 영상 확보 여부가 침수구역 산정의 정확성을 결정짓는 것으로 나타났다.