• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1393-1405
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• 2020

UAV (Unmanned Aerial Vehicle) can acquire high-resolution images due to low-altitude flight, and it can be photographed at any time. Therefore, the UAV images can be updated at any time in map production. Due to these advantages, studies on the possibility of producing large-scale digital maps using UAV images are actively being conducted. Precise digital maps can be used as base data for digital twins or smart cites. For producing a precise digital map, precise sensor modeling using GCPs (Ground Control Points) must be preceded. In this study, geometric models of UAV images were established through a precision sensor modeling algorithm developed in house. Then, a digital map by stereo plotting was produced to evaluate the possibility of large-scale digital map. For this study, images and GCPs were acquired for Ganseok-dong, Incheon and Yeouido, Seoul. As a result of precision sensor modeling accuracy analysis, high accuracy was confirmed within 3 pixels of the average error of the checkpoints and 4 pixels of the RMSE was confirmed for the two study regions. As a result of the mapping accuracy analysis, it satisfied the 1:1,000 mapping accuracy announced by the NGII (National Geographic information Institute). Therefore, the precision sensor modeling technology suggested the possibility of producing a 1:1,000 large-scale digital map by UAV images.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.111-121
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• 2018

RIn this research, digital elevation models, true-ortho image and 3-dimensional digital complied data was generated and evaluated using unmanned aircraft vehicle stereoscopic images by applying photogrammetric principles. In order to implement stereoscopic vision, digital Photogrammetric Workstation should be used necessarily. For conducting this, in this study GEOMAPPER 1.0 is used. That was developed by the Ministry of Trade, Industry and Energy. To realize stereoscopic vision using two overlapping images of the unmanned aerial vehicle, the interior and exterior orientation parameters should be calculated. Especially lens distortion of non-metric camera must be accurately compensated for stereoscope. In this work. photogrammetric orientation process was conducted using commercial Software, PhotoScan 1.4. Fixed wing KRobotics KD-2 was used for the acquisition of UAV images. True-ortho photo was generated and digital topographic map was partially produced. Finally, we presented error analysis on the generated digital complied map. As the results, it is confirmed that the production of digital terrain map with a scale 1:2,500~1:3,000 is available using stereoscope method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.645-651
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• 2007

In general, contours in digital vector maps, which represent terrain characteristics and shape, are created by 3D digitizing the same height points using aerial photographs on the analytical or digital plotters with stereoscopic viewing. Hence, it requires lots of task, and subjective decision and experience of the operators. DTMs are generated indirectly by using contours since the national digital maps do not include digital terrain model (DTM) data. In this study, model key points which depict the important information about terrain characteristics were extracted from the contours. Further, determination of the efficient and flexible grid sizes were proposed to generate optimal DTM in terms of both quantitative and qualitative aspects. For this purpose, a progressive sampling technique was implemented, i.e., the smaller grid sizes are assigned for the mountainous areas where have large relief while the larger grid sizes are assigned for the relatively flat areas. In consequence, DTMs with multi-grid for difference areas could be generated instead of DTMs with a fixed grid size. The multi-grid DTMs reduce computations for data processing and provide fast display.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.687-695
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• 2011

Many internet portals provide maps with spatial information services. Recently, various images including aerial, satellite, street view, and photo-realistic 3D city models are provided as well as maps. This study suggested a method for geometric correction of the panoramic aerial images in the internet portal and 3D building modeling using information which is available in the internet. The key of this study is to obtain all necessary data easily from internet without restrictions. Practically, the ground control coordinates could be available from geo-referenced internet maps, and stereo pairs of the aerial images and close-range photographs for photo-realistic object modeling are provided by the internet service. However, the ground control points are not suitable for accurate mapping. RMSE of the plotting was about 9 meters and reduced upto 4 meters after coordinate transformation. The proposed methods would be applicable to various applications of photo-realistic object modeling which do not require high accuracy.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.1-10
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• 2012

Recent spatial information technology has brought innovative improvement in both efficiency and accuracy. Especially, airborne LiDAR system(ALS) is one of the practical sensors to obtain 3D spatial information. Constructing reliable 3D spatial data infrastructure is world wide issue and most of the significant tasks involved with modeling manmade objects. This study aims to create a test data set for developing automatic building modeling methods by simulating point cloud data. The data simulates various roof types including gable, pyramid, dome, and combined polyhedron shapes. In this study, a robust bottom-up method to segment surface patches was proposed for generating building models automatically by determining model key points of the objects. The results show that building roofs composed of the segmented patches could be modeled by appropriate mathematical functions and the model key points. Thus, 3D digitizing man made objects could be automated for digital mapping purpose.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.179-188
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• 2008

This study aims for generating a city spatial model required for the creation of a 3D noise map. In this study, we propose an efficient method to generate 3D models of the terrain and buildings using only a digital map and draft maps previously established without using any sensory data. The terrain model is generated by interpolating into a grid the elevation values derived from both the contour lines and the elevation point of the digital map. Building model is generated by combining the 2D building boundaries and the building elevations extracted from the digital map and the draft map, respectively. This method has been then applied to a digital map and three sets of draft maps created in the different times. covering the entire area of Yeongdeungpo-gu. The generated city spatial model has been successfully utilized for the noise analysis and the 3D visualization of the analysis results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.1
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• pp.89-96
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• 2005

With acquisition of satellite image being facilitated due to recent advancement in Electro optical and astronautic technologies, focus on establishment of Geoinformation and analysis using satellite images have increased. This research have conducted digital plotting and digitizing operation, utilizing stereo images and grey level images provided by SPOT5 satellite and evaluated the accuracy through comparison and analysis with digital map results. Digital plotting results acquired using stereo images have been compared and analyzed on the basis of scale 1:25,000 digital map results published by National Geographic Information Institute. Accuracy of 20 check points have showed RMSE results 5.369 m at X (Easting) and 4.718 m, digitizing using grey level images showed RMSE results 7.616 m in X (Easting) and Y (Northing) 6.532 m. This is within the allowance of accuracy standards for scale 1:25,000 maps, and although digitizing operation was confirmed to have lower accuracy than that of digital plotting, using the former is considered to be more effective in terms of economical efficiency.

• 한국공간정보시스템학회:학술대회논문집
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• 2002.03a
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• pp.59-64
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• 2002

컴퓨터 그래픽스 기술과 H/W의 발달로 3D GIS에 대한 연구가 활발히 진행되고 있다. 최근 3D GIS에 대한 활발한 연구 중 3D 가상도시의 구축이 중요한 연구로 떠오르고 있다. 3D 가상도시는 국방, 교통, 통신, 지적, 지하시설물, 관광, 도시계획, 도시모델링 등에 다양하게 활용될 수 있다. 현재 우리나라에서 3D 가상도시의 구축은 미약하지만 앞으로 그 수요는 더욱 더 많아질 것이다. 3D 가상도시의 구축에는 GIS, 컴퓨터 그래픽스, Database, 자료구조, 3D 모델링 등의 다양한 기술이 필요하다. 3D 가상도시의 구축의 방법은 크게 1/1,000수치지도+실제측량, 1/1,000수치지도+입체 인공위성 영상+수치사진측량, 1/1,000수치지도+항공사진측량 도화원도, 1/1,000수치지도+항공레이저스캐닝의 방법을 적용해 볼 수 있다. 현재 우리나라 여건상 첫 번째 방법이 가장 일반적으로 사용이 되나 도화원도에 대한 규제를 완화하여 세 번째 방법을 적용하는 것이 가장 효과적일 것이다. 3D 가상도시는 인터넷 기술과 접목이 되어 3D Web GIS의 형태로 앞으로의 GIS 주류를 이룰 것이다. 그러나 국내에서 3D 가상도시의 구축에 관한 연구는 미약한 수준이다. 3D 자료취득, 자료처리, 모델링 부문에 대한 연구가 시급하다.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.197-210
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• 2012

The KOrea Multi-Purpose SATellite(KOMPSAT)-2 has a capability to provide a cross-track stereo imagery using two different orbits for generating various spatial information. However, in order to fully realize the potential of the KOMPSAT-2 stereo imagery in terms of mapping, various tests are necessary. The purpose of this study is to evaluate the possibility of mapping using the KOMPSAT-2 stereo imagery. For this, digital plotting was conducted based on the stereoscopic images. Also the Digital Elevation Model(DEM) and an ortho-image were generated using digital plotting results. An accuracy of digital plotting, DEM, and ortho-image were evaluated by comparing with the existing data. Consequently, we found that horizontal and vertical error of the modeling results based on the Rational Polynomial Coefficient(RPC) was less than 1.5 meters compared with the Global Positioning System(GPS) survey results. The maximum difference of vertical direction between the plotted results in this study and the existing digital map on the scale of 1/5,000 was more than 5 meters according as the topographical characteristics. Although there were some irregular parallax on the images, we realized that it was possible to interpret and plot at least seventy percent of the layer which was required the digital map on the scale of 1/5,000. Also an accuracy of DEM, which was generated based on the digital plotting, was compared with the existing LiDAR DEM. We found that the ortho-images, which were generated using the extracted DEM in this study, sufficiently satisfied with the requirement of the geometric accuracy for an ortho-image map on the scale of 1/5,000.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.291-297
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• 1998

In order to accomplish the digital map production I/O devices should be used which are used for data input procedure to convert original paper map(hardcopy) data into computer compatible digital map data, and for the mapsheet output procedure of worked out data. For the input device, digitizer and scanner are most frequently used. Digitizer has possibility of direct production of digital data, and are mainly used for input procedure of partly plotted source map. In contrary, scanner is rather easy to operate the instrument, so that is widely used for the input procedure of original sheet map. In this study, to extract the input device characteristics, some kinds of digitizers and scanners were cheesed and used for the positional error analysis through the operational method and types of instruments. Also for the output device characteristics, some kinds of plotter and materials are used and compared to analyze the positional error through the instrumental types and output sheet materials.