• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.328-331
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• 2008

It is possible to extract qualified ground control points (GCPs) solely from SAR data without published maps. TerraSAR-X is now in orbit and provides valuable data that have one of the highest spatial resolutions among civilian SAR systems. In this study, a sophisticated method for GCP coordinate extraction from TerraSAR-X stripmap mode data with a 3 m resolution was tested and the quality of the extracted GCPs was evaluated. An inverse-geolocation algorithm was applied to obtain GCPs from TerraSAR-X data. SRTM 90m DEM was used as an auxiliary data set for azimuth time correction of the SAR data. Mean values of the distance errors were 0.11 m and -3.96 m with standard deviations of 6.52 m and 5.11 m in easting and northing, respectively. The result is one of the best among GCPs possibly extracted from current civilian remote sensing systems. The extracted GCPs were used for geo-rectification of an IKONOS image, which demonstrated the applicability of the GCPs to geo-rectification of high resolution optic image. The method used in this study can be applied to KOMPSAT-5 for geo-rectification of high-resolution optic images acquired by KOMPSAT-2 or follow-up missions.

• Journal of the Korean earth science society
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• v.32 no.2
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• pp.190-199
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• 2011

A photovoltaic energy map that included a topography effect on the Korean peninsula was developed using the Gangneung-Wonju National University (GWNU) solar radiation model. The satellites data (MODIS, OMI and MTSAT-1R) and output data from the Regional Data Assimilation Prediction System (RDAPS) model by the Korea Meteorological Administration (KMA) were used as input data for the GWNU model. Photovoltaic energy distributions were calculated by applying high resolution Digital Elevation Model (DEM) to the topography effect. The distributions of monthly accumulated solar energy indicated that differences caused by the topography effect are more important in winter than in summer because of the dependency on the solar altitude angle. The topography effect on photovoltaic energy is two times larger with 1 km resolution than with 4 km resolution. Therefore, an accurate calculation of the solar energy on the surface requires high-resolution topological data as well as high quality input data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.337-343
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• 2004

Spatial information could be obtained from spaceborne high resolution optical and synthetic aperture radar(SAR) images. However, some satellite images do not provide physical sensor information instead, rational polynomial coefficients(RPC) are available. The objectives of this study are: (1) 3-dimensional ground coordinates were computed by applying rational function model(RFM) with the RPC for the stereo pair of Ikonos images and their accuracy was evaluated. (2) Interferometric SAR(InSAR) was applied to JERS-1 images to generate DEM and its accuracy was analysis. (3) Quality of the DEM generated automatically also analyzed for different types of terrain in the study site. The overall accuracy was evaluated by comparing with GPS surveying data. The height offset in the RPC was corrected by estimating bias. In consequence, the accuracy was improved. Accuracy of the DEMs generated from InSAR with different selection of GCP was analyzed. In case of the Ikonos images, the results show that the overall RMSE was 0.23327", 0.l1625" and 13.70m in latitude, longitude and height, respectively. The height accuracy was improved after correcting the height offset in the RPC. i.e., RMSE of the height was 1.02m. As for the SAR image, RMSE of the height was 10.50m with optimal selection of GCP. For the different terrain types, the RMSE of the height for urban, forest and flat area was 23.65m, 8.54m, 0.99m, respectively for Ikonos image while the corresponding RMSE was 13.82m, 18.34m, 10.88m, respectively lot SAR image.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.127-137
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• 2018

Recently, UAVs and Drones have been used for various applications. In particular, in the field of surveying, there are studies on the technology for monitoring the terrain based on the high resolution image data obtained by using the UAV-equipped digital camera or various sensors, or for generating high resolution orthoimage, DSM, and DEM. In this study, we analyzed the accuracy of GCP(Ground control point) matching using UAV and VRS-GPS. First, we used VRS-GPS to pre-empt the ground reference point, and then imaged at a base altitude of 150m using UAV. To obtain DSM and orthographic images of 646 images, RMSE was analyzed using pix4d mapper version As a result, even if the number of GCP matches is more than five, the error range of the national basic map(scale : 1/5,000) production work regulations is observed, and it is judged that the digital map revision and gauging work can be utilized sufficiently.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.748-752
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• 2008

Various services are developed from advancement of satellite imagery methodologies and internet infrastructure expansions. However, most of these services still rely upon low-resolution satellite images combined with DEM models. In this paper, we have implemented the raw data processing modules and other modules that transfer and render high-spatial resolution satellite images for efficient streaming services in web environments. By utilizing the Bukhan-mountain data as a pilot study, the paper has proposed the efficient approach to solve graphical problems in real time processing the large geographical area.

• Proceedings of the KSRS Conference
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• v.1
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• pp.430-431
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• 2006

KOMPSAT-2 was successively launched on July 28,06. She carries Fine Spatial Resolution Sensor with three channels. It is 4m monochromatic and 1m panchromatic. The main purposes would derive fine urban map and digital elevation model(DEM).Therefore we extend to coastal environment monitoring using the adjacent effect of radiation due to an interaction of radiation between heterogeneous surface and atmosphere. With data analysis of ASTER on TERA, which is 15m resolution in visible and near infrared wavelengths, we found atmospheric aerosols were always large. Note that data analysis was limited in Nagoya bay, Lake Tahoe, California & La Pozuelos, La Picasa, Argentina. Thus this time we expect data analyses around isolated island and peninsula in west and south coast of Korea.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.50-66
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• 2010

In this study, we performed a GIS-based debris flow simulation using the high-resolution airborne LiDAR DEM in order to establish the effective and resonable debris prevention plans in Korea. To do so, we set a study area to an specific region over Pyeochang-gun in Kangwon-do which showed the extreme rugged distribution of topography and simulated a possibility of debris flow occurrence in this area using a GIS-based numerical simulation program which was developed by applying the finite difference method. After that, we also performed the debris flow simulation by SINMAP and geomorphic analysis method in the same region and compared each result with that of GIS-based debris simulation for verifying the reliability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.47-52
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• 2008

The visual implementation of 3-dimensional national environment is focused by the requirement and importance in the fields such as, urban planing, telecommunication facility deployment plan, railway construction, construction engineering, spatial city development, safety and disaster prevention engineering. The currently used DEM system based on the 2-D digital maps and contour lines has limitation in implementation in reproducing the 3-D spatial city. Currently, the LiDAR data which combines the laser and GPS skill has been introduced to obtain high resolution accuracy in the altitude measurement in the advanced country. In this paper, we first introduce the LiDAR based researches in advanced foreign countries, then we propose the data generation scheme and an solution algorithm for the optimal management of our 3-D spatial u-City construction. For this purpose, LiDAR based height data transformed to DEM, and the realtime unification of the vector via digital image mapping and raster via exactness evaluation is transformed to make it possible to trace the model of generated 3-dimensional model with long distance for 3D u-city model generation.

• Journal of Cadastre & Land InformatiX
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• v.54 no.2
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• pp.97-109
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• 2024

This study presents a methodology for generating LoD1 objects using 2D spatial data in Shapefile format, converting them into CityGML 3.0 standard files, and applying textures for validation. High-resolution Z-values were extracted using DEM data, and a constrained Delaunay triangulation algorithm was applied to create LoD1 objects efficiently. Orthophoto TIF files were used as textures for these generated objects to achieve realistic visual representation. Finally, the CityGML 3.0 Validator tool was used to verify that the generated LoD1 models comply with the CityGML 3.0 standard. This research offers an efficient LoD1 object generation and texture application method that enhances visual realism, which can be beneficial for urban planning, disaster management, and smart city implementation.