• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.319-325
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• 2011

It has been used not orthometric height but normal orthometric height for the official height in Korean benchmark because it has been used not observed gravity but normal gravity for the computation of orthometric correction. The purpose of this study is to propose height renewal method of Korean benchmark. For this purpose, we observed gravity by CG5 digital gravimeter in both the first benchmark line between Sokcho and Gangneung area and the second benchmark line between Soksa and Inje area. We calculated relative gravity value and orthometric correction in all benchmarks. So, the maximum orthometric correction shows -0.349mm in the first benchmark line, and the maximum orthometric correction shows -44.060mm in the second benchmark line. In conclusion, we can confirm that the orthometric correction based on observed gravity is necessary for more accurate official height computation in the Korean benchmark.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.2 no.1
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• pp.54-64
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• 1984

This paper is a study on structural measurement by using a terrestrial camera. The aim of this paper is to understand the method of a composition by analyzing the geometrical compositive ratio of threestoried pagodas at Gamun-Sa, Gosun-Sa, Bulguk-Sa, Seated iron Buddha in Kwang-Jn, and Main-Seat Buddha at Sukkuram Cave-temple. Measured data and contour maps are accurately obtained by means of photogrammetry, and the following points are able to he found by analyzing them. At first, for Stone Pagodas. the breaths of the Okgesuks are made to the ratio, 8 : 7 : 6. And when an equililateral triangle and an 45$^{\circ}$ isosceles triangle are drawn of which the bases are the length of the upper Gabsuk, and then a circle is drawn whose radius is the length between the vertexes of the two triangles and its center is the vertex of the former the circle passes the upper line of the third Oksin. Also it can be found that an $70^{\circ}$ isosceles triangle being drawn at base line, the triangle passes the edge point of the upper Gabsuk and the center of the third Okgesuk. Also for Budha statues, it can be found that circles whose center is that of eyes can be drawn, and if 2 lines which pass the shoulder and the center of Buddha's body are extended, they intersect the knees.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.99-107
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• 2016

In order to maintain the precise positioning accuracy of the VLBI system, the shape deformation found in antenna structure should be monitored. In fact, reduced the antenna gaining of an electromagnetic wave reception from the Quasar has been particularly expected due to the shape deformation of main reflector in VLBI antenna. Therefore, the importance of shape deformation monitoring for the main reflector has been significantly increased. The main reflector has come out as the high potential for deformation in the VLBI structure. The fact has led us to investigate the monitoring system for the main reflector based on the efficient algorithm in accordance with the close-range photogrammetry, which of expecting to be utilized as the continuous and automated monitoring system for the structure deformation in the near future. Ten fitting lines were estimated with the TLS for feature points of distributed in all directions from the main reflector. The resultant intersection point of estimated fitting lines was calculated by using the nearest point calculation algorithm, based on those non-intersection lines. Following to the intuitive basis for the time series analysis, the results was able to provide the calculation of numerical variation in the intersection point, which is represented in 3-axis,; that we are expecting to open the way for predicting a deformation rate as well as deformation direction

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.6 no.2
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• pp.34-41
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• 1988

Nowadays the considerable improvements, not only in photogrammetric equipment but also in adjustment methods have led to a high accuracy of Aerial Triangulation and reach the step to obtain A.T. technique that uses Global Position System without ground control survery. The enterance of analytical plotter have made considerable development both in accuracy and in efficiency and improved working environment of A.T. by the combination of On-Line Analytical Plotting System. In this paper, in A.T., with using of analytical polotter, aims to improve the acccuracy in coordinates determination of low level control point. The result shows that in case of A.T. with analytical plotter AVIOLYT BC2, the accuracy of control points improves to 7% in planimetry and to 40% in height compared to A.T. with precision plotter Autograph A-8.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.2
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• pp.171-183
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• 2016

Small-scale maps currently used are made by scanning and editing printed maps and its shortcoming is accumulated errors at the time of editing and low accuracy. TM projection method is used but its accuracy varies. In addition, small-scale maps are made without consideration of usability and compatibility with other scale maps. Therefore, it is necessary to suggest projection and coordinates system improvement methods in consideration of usability and compatibility between data. The results of this study reveal that in order to make the optimum small-scale map, projection that fits the purpose of map usage in each scale, coordinate system and neat line composition should be selected in consideration of interrelation and compatibility with other maps. Conic projection should be used to accurately illustrate the entire country, but considering usability and compatibility with other maps, traversing cylindrical projection should be used instead of conic projection. For coordinates system of the small-scale map, Universal Transverse Mercator (UTM-K) based on the World Geodetic System should be used instead of conventional longitude and latitude coordinate system or Transverse Mercator.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.325-333
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• 2004

Since 1995, One of the NGIS(National Geographic Information System) projects, the underground utilities project has been finished in 2003. The 19 cities in korea for this project will use underground utilities management system using underground utilities database focusing on water and sewage system. However, special expert, technical and experience problem in computer environment has not been had in working department for water and sewage management and maintenance for each local government. The management and maintenance of underground utilities database by manual method is getting lowered a data quality of underground utilities database because of the data omitting, error in writing and securing of the lasted database. Therefore, in this study, Application test for field workers using a mobile tool and environment analysis of wireless communication in Korea and application test of GPS receiver for mobile tools had been processed and made a mobile working environment. The efficient management and maintenance method for underground utilities database has been developed an off- line method for modification and update of database about general work which has a high working frequency because of the limitation of wireless communication environment Also, the emergency working has been applied for on-line method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.4
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• pp.405-413
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• 2002

It is crucial that we should set proper standards capable of efficiently handling new corrections of maps, connections of edges on the maps, administrative districts, and inter-scale connections in order to make serial cadastral maps. This study drew a two dimensional Parameter using an indent point, as a Review Control Point, on forest screening line or boundary line of administrative district. The study also introduced a few different transformations such as Affine Transformation, N-Degree Polynomial Transformation, and Projective Transformation, the two dimensional transformation methods to apply them to the connection of cadastal·forestry maps and the connection of parcels between the administrative districts, on the forestry map designed by discretionary edges on the maps per district unit with parcel numbers and tried to apply the coordinates transformation method to connections of maps to make serial cadastral maps.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.137-143
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• 2002

In this study we generated digital orthophoto from LIDAR data. To generate digital orthophoto, we make TIN from raw laser scanning data(XYZ point data) and compiled DSM from this TIN. In this procedure much noise appeared along the break lines in DSM and this can give bad effect to the quality of digital orthophoto. Therefore, we applied various techniques which can refine the break line. In the result, we concluded that the fusion of LIDAR DEM of lowland and extracted buildings was adequate to generating DSM. So we generated the digital orthophoto from DSM generated from this technique. In the result of quality test, the positional accuracy of this digital orthophoto was better than the positional accuracy of 1:5,000 map.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.301-303
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• 2003

The extraction of 3D road network from high-resolution aerial images is still one of the current challenges in digital photogrammetry and computer vision. For many years, there are many researcher groups working for this task, but unt il now, there are no papers for doing this with TLS (Three linear scanner), which has been developed for the past several years, and has very high-resolution (about 3 cm in ground resolution). In this paper, we present a methodology of road extraction from high-resolution digital imagery taken over urban areas using this modern photogrammetry’s scanner (TLS). The key features of the approach are: (1) Because of high resolution of TLS image, our extraction method is especially designed for constructing 3D road map for next -generation digital navigation map; (2) for extracting road, we use the global context of the intensity variations associated with different features of road (i.e. zebra line and center line), prior to any local edge. So extraction can become comparatively easy, because we can use different special edge detector according different features. The results achieved with our approach show that it is possible and economic to extract 3D road data from Three Linear Scanner to construct next -generation digital navigation road map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.2
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• pp.55-62
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• 2019

The stereo geometry establishment based on the precise sensor modeling is prerequisite for accurate stereo data processing. Ground control points are generally required for the accurate sensor modeling though it is not possible over the area where the accessibility is limited or reference data is not available. For the areas, the relative orientation should be carried out to improve the geometric consistency between the stereo data though it does not improve the absolute positional accuracy. The relative orientation requires conjugate points that are well distributed over the entire image region. Therefore the automatic conjugate point extraction is required because the manual operation is labor-intensive. In this study, we applied the method consisting of the key point extraction, the search space minimization based on the epipolar line, and the rigorous outlier detection based on the RPCs (Rational Polynomial Coefficients) bias compensation modeling. We tested different parameters of window sizes for Kompsat-2 across track stereo data and analyzed the RPCs precision after the bias compensation for the cases whether the epipolar line information is used or not. The experimental results showed that matching outliers were inevitable for the different matching parameterization but they were successfully detected and removed with the rigorous method for sub-pixel level of stereo RPCs precision.