• Journal of Korean Society for Geospatial Information Science
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• v.2 no.2 s.4
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• pp.131-142
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• 1994

Generally, there are two methods which generates the base map of Geo-Spatial Information System(GSIS). one is the digitizing of existing map, and the other is the analytical plotting method editing data acquired by sensors using computers. But the analytical plotting method and method of the digitizing of existing map is technically complex and has the disadvantages in the costs and time. The subject region of study(the Kwangyang province), was photographed by aircraft, and photographing scale was 1/6,000. Then this area was divided into two specific regions, the residential area, and the agricultural area. In this study, we developed the algorithm that generated base map of database in GSIS from the aerial photo. This algorithm is as followed. First, the digital aerial photos were generated using these aerial photos. Second, these digital aerial photos were enhanced by implementing the histogram equalization. Third, the objects of the enhanced images were extracted by implementing thresholding and edged detection techiques of image segmentation. Finally, these images could be used to updated the base map of database in GSIS. The result obtained from this study showed that method used by this study were more efficient than existing method in costs and time.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2006.05a
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• pp.138-145
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• 2006

Recently the extraction of building height information has been investigated using remotely sensed image and digital maps. In this study, based on the digital photogrammetry principle and mono imagery method the building height information can be extracted by using relationship between ground coordinates and image coordinates, To evaluate the result the comparison was done with building height from 1:5000 aerial photo. The experiment shows that extraction of building height could be performed using IKONOS single imagery and digital map and it is proved that the building height could be reconstructed within some extent.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.831-837
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• 2009

This paper suggests the method for saving the digital map which was made through aerial photography to ORDBMS (Object Relational Database Management System) and analyze its efficiency through experiments. The digital map has been used by file units because of managing or providing it to others. But this way can not get sequential graphic entities and just use it which was included in only one map. In this paper, we saved the digital map to ORDBMS at a time after converted the digital map entities based on the tile to the things can be inserted to ORDBMS. And, we also proved the possible methods to extract the graphic entities what we need from entire blueprint through experiments.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1998.11a
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• pp.49-53
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• 1998

서울시 수치지형도를 유지관리하기 유지관리의 제도적, 기술적 방안과 유통 및 공급방안이 수립되어야 한다. 본 연구에서는 제도적 방안을 위해 갱신주체, 대상 지형지물, 갱신주기, 공공 측량 승인 및 심사절차, 행정적인 절차 등의 요인을 분석하여 네 가지 방안을 제시하였고 기술적 방안을 위해 현재 수치지형도를 갱신할 수 있는 도면에 의한 디지타이징, 수정도화, 항공사진 스캐닝에 의한 방법, 수치정사사진에 의한 방법 등을 비교·분석하였다. 또한 유통 및 공급방안을 위해 공급대상, 공급내용, 공급형태, 공급방법 등을 분석하였다. 이러한 분석을 통해 현재 제작완료 단계에 있는 서울시 수치지형도의 유지관리 및 공급을 위한 최적의 방안을 제시할 수 있었다.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.1 s.39
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• pp.67-73
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• 2007

Recently, three-dimensional (3D) GI (Geospatial Information) using LiDAR system has been used various fields such as the production of digital map, the modeling of 3D building and urban area, and analysis of communication network and environmental effect. In this study, the production cost of digital map by aerial LiDAR surveying were compared with the cost by aerial photograph surveying for analysis of economical efficiency. It is expected that the results of this study will be used base data for production, update, revision of digital map and curtail effect of national budget.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.49-62
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• 2005

The VR (virtual reality) simulator such as helicopter simulation needs virtual environment of existing urban area. But the real urban environment keeps changing. We need a modeling method to make use of the GIS data that are updated periodically. The flight simulation needs to visualize not only buildings in near distance but also a large number of buildings in the far distance. We propose a method for modeling urban environment from aerial image and digital map with a comparatively small manual work. Image based modeling is applied to urban model which considers the characteristic of Korean cities. Buildings in the distance can be presented without creating a lot of polygons. Proposed method consists of the pre-processing stage which prepares the model from the GIS data and the modeling stage which makes the virtual urban environment. The virtual urban environment can be modeled with the simple process which utilizes the height map of buildings.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1822-1826
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• 2010

본 연구의 지리정보시스템(GIS)을 이용한 야계의 입지해석모델 개발은 사방댐 하류 야계에 대한 야계사방사업의 위치 선정, 하도계획 및 구조물 계획 등을 기 구축되어 있는 국가 DB와 강우 강도 산정, 홍수유출해석 및 수리계산 소프트웨어를 연계하여 체계적으로 표준화된 시스템을 구축하는 것이 목표이다. 따라서, 본 연구에서는 강우, 지형 지질 토지이용 자료를 이용하여 홍수유출해석을 통해 기본 홍수량을 산정하고, 홍수량과 수치지형도 및 항공사진으로부터 추출한 야계의 종단, 평면 및 횡단지형정보를 기본자료로 HEC-RAS의 지형자료(geometry data) 및 흐름자료(flow data)를 구축하여 수리계산을 수행하였다. 수리계산 결과를 토대로 종단, 평면, 횡단의 하도계획과 호안, 수제 및 하상유지공 등 구조물 계획 등에 필요한 야계입지해석모델을 개발하고자 하였다. 연구결과 강우, 지형 지질 토지이용, 항공사진 자료 등 국가 DB자료만을 이용하여 야계입지를 해석할 수 있는 시스템을 개발하였으며, 1 : 5000의 수치지형도 및 항공사진으로부터 야계부분에 대한 지형도를 분리하여 1m 간격의 등고선으로 된 수치지형도에서 야계의 종단, 평면 및 횡단지형정보를 기본자료로 수리계산을 위한 HEC-RAS의 지형자료(geometry data)를 구축할 수 있음을 제시하였다. 또한 수리계산 결과를 토대로 최심하상고, 수위, 수심, 유속, 소류력, Froude수 등 종단, 평면, 횡단의 하도계획과 호안, 수제 및 하상유지공 등 야계 구조물 계획 등에 필요한 수리학적 인자를 추출할 수 있었으며, 시험유역에 대한 적용 가능성을 검토한 결과 야계사방사업의 입지선정을 위한 수단으로 활용할 수 있음를 제시하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.121-128
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• 2009

The King George Island, where the King Sejong Station is located, represents one of the gateways to the Antarctica from the point of its geographical aspect. It also serves as an advanced post, and plays an important role in the extending for Korea's Antarctic research activities. The existence of maps is not only a basic element for the constructing geographic informations supporting these activities, but also an implied way of announcing the sovereignty over the KingSejong Station in global world. However, the precise surveying for the geographic information has not been carried out, and thus topographical maps as well as geographic information assuring enough accuracy are still missed in this area. This fact had forced Korea to rely on using maps produced by foreign countries. Therefore, this study aims to generate digital topographical maps of 1: 5,000 scale for the constructing geographic information using lightweight aerial photogrammetry system first. And further, it will contribute to offer practical base data for the future research related to the Antarctic environment through the analysis of glacier retreat and change using this new digital map comparing with existing one.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.257-264
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• 2020

Vectorization is currently the main method in feature collection (extraction) during digital mapping using UAV-Photogrammetry. However, this method is time consuming and prone to gross elevation errors when extracted from a DSM (Digital Surface Model), because three-dimensional feature coordinates are vectorized separately: plane information from an orthophoto and height from a DSM. Consequently, the demand for stereo plotting method capable of acquiring three- dimensional spatial information simultaneously is increasing. However, this method requires an expensive equipment, a Digital Photogrammetry Workstation (DPW), and the technology itself is still incomplete. In this paper, we evaluated the accuracy of low-cost stereo plotting system, Menci's StereoCAD, by analyzing its three-dimensional spatial information acquisition. Images were taken with a FC 6310 camera mounted on a Phantom4 pro at a 90 m altitude with a Ground Sample Distance (GSD) of 3 cm. The accuracy analysis was performed by comparing differences in coordinates between the results from the ground survey and the stereo plotting at check points, and also at the corner points by layers. The results showed that the Root Mean Square Error (RMSE) at check points was 0.048 m for horizontal and 0.078 m for vertical coordinates, respectively, and for different layers, it ranged from 0.104 m to 0.127 m for horizontal and 0.086 m to 0.092 m for vertical coordinates, respectively. In conclusion, the results showed 1: 1,000 digital topographic map can be generated using a stereo plotting system with UAV images.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.115-120
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• 2009

Point-based methods with experienced human operators are processed well in traditional photogrammetric activities but not the autonomous environment of digital photogrammetry. To develop more robust and accurate techniques, higher level objects of straight linear features accommodating element other than points are adopted instead of points in aerial triangulation. Even though recent advanced algorithms provide accurate and reliable linear feature extraction, extracting linear features is more difficult than extracting a discrete set of points which can consist of any form of curves. Control points which are the initial input data and break points which are end points of piecewise curves are easily obtained with manual digitizing, edge operators or interest operators. Employing high level features increase the feasibility of geometric information and provide the analytical and suitable solution for the advanced computer technology.