• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.151-156
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• 2004

현재 전국에 산재해 있는 많은 소규모의 저수지들은 현재까지 관리 상태나 실지 내용적에 대한 정확한 자료가 모두 구비되어있지 못한 실정이다. 본 연구에서는 행정구역상 저수지가 많이 분포되어있는 영남권의 경주시 73개 소규모 저수지 가운데 23개소를 선정하여 실험을 하였다. RKT-GPS를 이용하여 5초마다 데이터를 취득하였고, E/S를 이용하여 1초 간격으로 수심에 대한 값과 TS를 이용하여 현황 측량을 실시하였다. 이렇게 취득된 자료를 가지고 3D 모델링을 하여본 결과 15개소(약 65%)의 저수지가 양호한 상태였음을 알 수 있었고, 과거자료와의 비교ㆍ분석을 통하여 현재 저수지 상태에 대한 정확한 내용적을 알 수 있었다. 또한 23개소 저수지의 만수면적과 유효저수량을 분석한 결과 만수면적은 20.63%, 유효저수량은 3.34 %만큼 줄어들었음을 알 수 있었다. 이를 통하여 현재 저수지 상태에 대한 분석과 관리 방향에 대한 방법에 대하여 기여하고자 한다.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.344-347
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• 2006

급변하는 자연환경과 연안개발에 따른 해안침식이 가속화 되고 있어 사회, 경제적으로 해안침식문제가 부각되고 있다. 본 연구에서는 이러한 해안침식이 진행되고 있는 국내 최고의 해수욕장인 해운대 해수욕장의 장기해안지형변화에 대해 분석하였다. 항공사진은 실측과는 달리 경제적이며 측량 위험 부담이 적고 비교적 위성영상에 비해 고해상도라는 장점이 있으므로 이를 활용하였다. 지난 60여 년간의 항공사진을 이용하여 해안선을 추출하고 해빈면적을 산출하였다. 그리고 수심측량 및 GPS 측량 자료를 이용하여 보정거리와 보정면적을 계산함으로써 조위를 보정해주었다. 연구 결과, 해운대 해수욕장의 해안선이 점진적으로 후퇴하고 있으며 해수욕장 면적이 전체적으로 감소하고 있는 것으로 나타났다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.265-268
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• 2004

At these days, electronic maritime chart is in positively using various fields. But most of electronic maritime chart and topography information system is hard to using various fields despite that demand because that difficult approach from separately and specific constitution. This thesis apply to image filtering that extract requirement topography data from simplification of the whole system. And as constructing database of simple structure that getting various information from sounding depth and existing database, propose electronic maritime chart system to practicable 3D embodiment. And also propose convenience and commonplace to simple process about frequently renewal.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.85-99
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• 2020

Reservoir is an important infrastructure of our society because it can store immense amount of water for various usages - manufacturing, agriculture, drinking, power generation, tourism etc. For maintenance of reservoir, various efforts in administrative and technological aspects are periodically conducted and monitoring the conditions of reservoir bed is the first priority for maintenance of reservoir. To check the conditions of reservoir bed, we measured depth of reservoir by using echo sounder, which is relatively reliable, prior to discharging of stored water and surveyed topography of reservoir by using UAV after discharging of water. Then, we conducted interpolation of measured depth of water by means of inverse distance weighting interpolation, Kriging interpolation, minimum curvature interpolation and radial basis function interpolation and calculated the volume of reservoir for each interpolation method. We compared the calculated volume of reservoir with the volume of water calculated by UAV after discharging of water and found the following results: First, as results of the above processes, we found that the Kriging interpolation was 97% correct in measurement of the volume of reservoir. Second, as results of comparison of differences between topographical areas and interpolated areas after selection of cross section for comparison, Kriging interpolation was found to have the most similar configuration with the topographical configuration by showing the least difference in the area of cross section. Therefore, it is determined that the optimal modeling of reservoir bed with the water depth data measured by echo sounder shall provide basic information for efficient maintenance of reservoir.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.39-46
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• 2010

Sounding data is the essential source for the safety of ships navigation system, and fundamental to the reasonable usage and maintenance of the ocean as well. As IT tech, positioning equipment such as GPS and INS, echo sounder are developed, recently, the precise submarine topography database bas been built by Multi-Beam Echo Sounder. However, MBES data includes some inevitable error caused by several factor, and some data have errors where the terrain is wobble. The error, which causes the $moir\acute{e}$ pattern error is the main factor hindering the accuracy of MBES data results, and therefore it is necessary to figure out the main cause of the error for the improvement of the accuracy by removing error data. On this research, the main cause of the error data is studied by analyzing motion sensor value of data including the $moir\acute{e}$ pattern error. Thus, as the result of examination, it turns out that the $moir\acute{e}$ pattern error is related to the standard deviation of Roll, and error data values are results of the non-correspondence between Swath data and Roll values caused by the drastic change of Roll values. Accordingly, the error data is removed by comparing between the gradient of Swath data and Roll values. Finally, as the result of removing error data, it is expected to be able to estimate the quality of MBES using the standard deviation of Motion sensor's Roll value, and calculate the additive error factor, which minimize non-corresponding data, and also this research must be contributed to improve the accuracy of sounding for small vessels with lots of motion in the bad circumstance for navigation.

• Journal of Korea Water Resources Association
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• v.56 no.spc1
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• pp.1027-1036
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• 2023

Coastal topographic information is crucial in coastal management, but point measurment based approeaches, which are labor intensive, are generally applied to land and underwater, separately. This study introduces an efficient method enabling land and undetwater surveys using an unmanned aerial vehicle (UAV). This method involves applying two different algorithms to measure the topography on land and water depth, respectively, using UAV imagery and merge them to reconstruct whole coastal digital elevation model. Acquisition of the landside terrain is achieved using the Structure-from-Motion Multi-View Stereo technique with spatial scan imagery. Independently, underwater bathymetry is retrieved by employing a depth inversion technique with a drone-acquired wave field video. After merging the two digital elevation models into a local coordinate, interpolation is performed for areas where terrain measurement is not feasible, ultimately obtaining a continuous nearshore terrain. We applied the proposed survey technique to Jangsa Beach, South Korea, and verified that detailed terrain characteristics, such as berm, can be measured. The proposed UAV-based survey method has significant efficiency in terms of time, cost, and safety compared to existing methods.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.71-78
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• 2008

Nowadays, echosouder has been widely used in sea survey and ship navigation. By utilizing echosounder, we can measure the depth of water reliability. However, the problem is that depth update rate drops remarkably when sea bottom is shallow or steep/rugged. Therefore, we have developed an optimized algorithm to process tranducer's soundwave signals at high-speed and minimize error. Processing algorithm is implemented by the latest DSP processor (TMS320F2812), consequently, high-speed data processing can be achieved. Performance of the proposed algorithm is verified by experiments and compared with existing algorithms. It has shown that our method results in higher precision in water depth measurement than other methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.2
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• pp.137-145
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• 2003

Currently, the availability of 3-D topographical survey by combination of GPS and Echo Sounder has been increased in the various field like as the construction of structure, the dredging and the reclamation in the ocean and river, and observation of topographic change in seabed or riverbed. In this case, the error of depth sounding can divide in form that is happened by combination of GPS and Echo Sounder, and form that is happened in Echo Sounder itself, In this study, in the case happen by Echo Sounder itself, analyzed error by specially about geological features of the seabed and riverbed that is specular surface of sound wave and wished to present solution way. The sounding error about the echo sounder and characteristic of estuary riverbed was found by understanding the relation of average diameter and residual error and we defined correction formula, Y=-0.00474$^{*}$In(X) -0.0045 by the regression analysis. and then we verified applicability of correction formula. As the result, if measure Preliminary investigation or pre-survey the geological features for the survey area at topographical survey of estuary riverbed, we presented the error correction formula that estimate and can correct of error by Echo Sounderer.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1097-1107
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• 2020

A methodology has been proposed to understand the spatiotemporal changes of the river topography through the longitudinal change of the geometric characteristics of the cross-sections and the properties related thereto. Three-dimensional spatial information of the riverbed was obtained through the detailed bathymetry survey using an acoustic echo sounder for the reach from Gumi Weir to Chilgok Weir in the Nakdong river. Geometric informations for the reference sections were extracted using the acquired bathymetry survey data. By comparing the geometric properties for the reference sections, it was possible to catch the topographic characteristics and its changes over a reach of the channel. Through comparison with past survey data, it was also possible to quantitatively grasp the amount of change in cross-sectional area and volumetric change of riverbed. It is expected that a quantitative evaluation of river topography changes will be possible by applying the method proposed in this study.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.3
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• pp.295-303
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• 2000

The purpose of this research is to enhance efficiency and tide measurement of the bathymetry survey based on the DGPS techniques which is becoming popular today due to a lot of benefits using the GPS. And according to the result of this research, choice and interpolation were possible with the most optimum method according to the various mathematical regressive equations as linear, parabolic, polynomic, reciprocal, hyperbolic, logarithmic and Gaussian functions. And the height of ground surface is easily calculated by 2D+1D transformation of coordinate of WGS84 in Cm-level based on the real time, even though the GPS time and tide were used to be synchronized through step-wised processing before. And because of the synchronization of time, the real time DGPS can cope with the loss of local current and changes of the tide.