• Spatial Information Research
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• v.12 no.1
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• pp.73-87
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• 2004

The Ministry of Construction and local governments have spent lots of money to construct 1: 1,000 scale digital topographic map. However the digital map is used only in facility management departments and the department in charge of GIS. In local governments, almost 70 ∼ 80 % of data are related with maps, which represents GIS technique and the digital maps could be used 70 ∼ 80 % of local government tasks. In this circumstances, it is necessary to spread out GIS usage through GIS education. However, there are lots of limits in GIS education such as number of people which can take classes at one time, physical location and size of classroom, and curriculums etc. To overcome these limits, cyber GIS education is becoming more important. This study presents how the cyber GIS education should be composed for the local government officers. For this purpose, this study accomplished followings ; grasp current GIS education status, analyze the needs of GIS education for local government officers, propose cyber GIS courses and curriculums according to the level of officers.

• Journal of Korean Society of Rural Planning
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• v.11 no.2 s.27
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• pp.9-19
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• 2005

The purpose of this study is to analyze the potential soil loss and hazard zone by the Revised Universal Soil Loss Equation(RUSLE) for preservation and management of land resources which is the base of ecosystem, and to grasp the relationship between RUSLE factors in the Nakdong River Basin. All thematic maps used in RUSLE are constructed through GIS and spatial analysis method derived from digital topographic maps, detailed soil maps, land-cover maps, and mean annual precipitation of 30 years collected respectively from National Geographic Information Institute, National Institute of Agricultural Science and Technology, and Ministry of Environment. The slope length of LS-factor that takes much times by the study area's wideness was calculated automatically through AML(Arc Macro Language) program developed by Van Remortel et al.(2001, 2003). The results are as follows; First, according to the soil loss estimation by the RUSLE, it shows that approximately 82% of the study area have relatively lower possibility of soil loss which is the 1 ton/ha in annual soil loss. While, 9.4% ($2,228km^2$) needed intensive and continuous management for soil loss. Because the amount of their annual soil loss was greater than 10 ton/ha that is optimum level suggested by Morgan(1995). For these areas, the author believe that a new approach which can minimize environmental impacts from soil loss through improvement of cultivation process and buffer forest zone should be applied. Second, according to the relationship between the RUSLE factors, topographical(LS-factor) and cover management(C-factor) conditions have a lot of influence on soil loss in case of the Nakdong River Basin. However, because of RUSLE factor's influence that affect to soil loss might be different based on the variety of spatial hierarchy and extent, it is necessary to analyze and evaluate factor's relationship in terms of spatial hierarchy and extent through field observations and further studies.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.548-551
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• 2007

Among components of digital topographic maps used officially in Korea, only contours have 3D values except buildings and trees that are demanded in landscape planning. This study presented a series of processes for 3Dreconstructing landscape features such as terrain, buildings and standing trees using LiDAR (Light Detection And Ranging) data and aerial digital photo graphs. The 3D reconstructing processes contain 1) building terrain model, 2) delineating outline of landscape features, 3) extracting height values, and 4) shaping and coloring landscape features using aerial photograph and 3-D virtual data base. LiDAR data and aerial photograph was taken in November 2006 for $50km^{2}$ area in Sorak National Park located in eastern part of Korea. The average scanning density of LiDAR pulse was 1.32 points per square meter, and the aerial photograph with RGB bands has $0.35m{\times}0.35m$ spatial resolution. Using reconstructed 3D landscape features, visibility with the growing trees with time and at different viewpoints was analyzed. Visible area from viewpoint could be effectively estimated considering 3D information of landscape features. This process could be applied for landscape planning like building scale with the consideration of surrounding landscape features.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.4
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• pp.331-338
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• 2004

This paper describes capability of utilizing ground control points(GCPs) obtained from 1:1,000 and 1:5,000 digital vector maps to correct image coordinates which have errors due to bais rational polynomial coefficient(RPC) of IKONOS Geo-level stereo images. The accuracy of the bias-corrected images was improved to approximately 4m and 2m in planimetry and height, respectively. The accuracy was also compared with results from using GCPs obtained by GPS surveying. In consequence, bias-compensated IKONOS sereo imagery was evaluated to satisfy generating topographic map 1:10,000.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.1-11
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• 2019

This study selected the national park area of Mt. Seorak in Inje-gun, Gangwon-do, where a lot of debris flow occurred due to the heavy rainfall and conducted a field survey. In addition, topographic spatial data were constructed using the GIS technique to analyze watershed characteristics. For the construction of terrain data after the disaster, the debris flow occurrence section was scanned and the 3D topographic data was constructed using the terrestrial LiDAR. LiDAR terrain data are compared to digital maps(before disaster) to assess precision and topographic data before and after the disaster were compared and analyzed. Debris flow diffusion area was calculated using FLO-2D model and compared debris flow occurred section.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.155-163
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• 2010

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board the NASA's Terra spacecraft provides along-track digital stereo image data at 15m resolution with a base-height ratio 0.6. Automated stereocorrelation procedure was implemented using the ENVI 4.1 software to derive DEMs with $15m{\times}15m$ in 43km long and 50km wide area using the ASTER stereo images. The accuracy of DEMs was analyzed in comparison with those which were obtained from digital topographic maps of 1:25,000 scale. Results indicate that RMSE in elevation between ${\pm}7$ and ${\pm}20m$ could be achieved. Excluding cloud, water and building areas as the factors which make RMSE value exceeding 10m, the accuracy of DEMs showed RMSE of ${\pm}5.789m$. Therefore for the purpose of elevating accuracy of topographic information, we intended to detect the cloud areas and shadow areas by a landcover classification method, remove those areas on the ASTER DEM and then replace with those areas detached from the cartographic DEM by band math.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.275-278
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• 2004

The geo-referencing of satellite imagery is a key task in remote sensing. GCPs are points the position of which is known both in the image and in the supporting maps. Mapping function makes the determination of map coordinates of all image pixels possible. Generally manual operations are done to identify image points corresponding to the points on a digital topographic map. In order to accurately measure ground coordinates of GCPs, differential global positioning system (DGPS) surveying are used. To acquire the sufficient number of well distributed GCPs is one of the most time-consuming and cost-consuming tasks. This paper describes the procedure of automatically extracting GCOs using GCP database. GCP image chips and image matching technique are used for automatic extraction of GCPs. We developed image processing tool for making image chip GCPs and Web Server for management of GCPs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.163-170
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• 1991

The 3 dimensional point positioning from SPOT imagery is performed by bundle adjustment methods of analytical and digital photogrammetry, and need the precise determination of image coordinates and accurate coordinates of ground control points. In this study, the authors analysed the digitized planimetric accuarcy and height accuracy of topographic maps in comparison with accurate coordinates by coordinates resulted by bundle adjustment in each cases between different acquisition method of ground control point coordinates and formats of SPOT imagery.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.519-521
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• 2005

In recent years, LiDAR(Light Detection and Ranging) data has been widely used to prepare digital elevation models(DEMs) with the high spatial resolution of centi-meters. This paper investigated possible applications of LiDAR-derived DEMs in surface hydrology modeling, such as characterizing flow direction, identifying sub-basins in a watershed, and calculating variables like upstream contribution area. The results were compared to the results of the DEMs from conventional topographic maps.

• Journal of the Korean Geographical Society
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• v.34 no.3
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• pp.319-336
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• 1999

본 연구는 우리나라의 수치지형도에서 수치고도모형(DEM)을 개발하고자 할 때 고려해야 할 요인들을 분석하였다. 특히 DEM의 정확도에 결정적으로 영향을 미치는 내삽법의 과정을 지형적 유형(평지.계곡.산지)과 공간적 표본추출법(체계적추출법.군집형무작위추출법.복합점진적표본추출법)에 따라 구분하여 살펴 보았다. RMSE의 측정을 통해 크리깅 내삽법이 지형의 기복에 산관없이 정확도를 유지함녀서 DEM을 생성할 수 있는 방법으로 평가되었다. 그리고 표본추출법에 따라 공간적 표본 밀도를 달리한 낮은 표본을 대상으로 한 경우에 비해 낮게 나타났다. 또한 본 연구에서 제안한 복합 점진적 표본추출법을 적용한 DEM의 정확도는 다른 표본추출법을 적용한 경우보다 그 정확도가 향상됨을 확인하였고, 반면에 계산상의 효율성이 다른 방법에 비해 떨어지는 단점을 보였다.