• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.82-92
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• 2014

The ratio of using soil as the main material in construction is quite numerous, and it covers many parts in forms and bases of the structure. Thus, the earthwork forms many structures for social infrastructure, and the stability of these structures is most crucial when completed than under construction. This study executed a field experiment to evaluate the accuracy and utility of the slope, which is an important part in earthwork, when terrestrial LiDAR is obtained, and the results are as follow. First, as the result of the observation using Total Station and terrestrial LiDAR, the horizontal error RMSE was ${\pm}2.2cm$, and the vertical error RMSE was ${\pm}3.0cm$. As the result of the comparison between the errors and permissible range of public surveying regulation, it sufficiently secure the accuracy. Also, the extraction of the check section, which covers the most important part among the stability checks could be scientifically and rationally processed, and these extraction results are expected to be provided as important basic materials for the earthwork slop stability evaluation.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2009.04a
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• pp.246-248
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• 2009

기존의 항공사진 및 위성사진을 활용한 원격탐사방법은 기상조건에 따른 제약과 3차원적 수직구조 관한 정보 수집에 한계가 있다. 따라서 보다 정확하고 신속한 산림자원 정보를 획득하기 위해서는 새로운 기술적 접근이 필요하다. 3차원 측정이 가능한 LiDAR의 특성을 이용하면 기존 방법의 부정확성과 비효율성을 상당부분 극복 할 수 있다. 본 연구에서는 지상 Laser Scanner 와 항공 LiDAR를 이용하여 개체목의 3차원 구조를 예측하여 수고, 지하고, 수관면적, 수관체적을 추정하고 결과를 비교하였다. 지상 Laser Scanner에 의한 측정치를 참조자료로 하여 항공 LiDAR의 개체목 측정 정확성을 향상 시킬 수 있는 보정식을 최종적으로 개발하였다.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.63-68
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• 2010

In this study, subject areas with different topographic feature were selected for the purpose of measuring the slope terrain by setting Terrestrial LiDAR in different places. And the slope terrain was analyzed based on three-dimensional raw data obtained through the measurement of slope terrain. With DEM data obtained from five measurement instances with 5mm of scan interval by setting Terrestrial LiDAR on the site 30m away straight from the slope terrain consisting of asphalt, rock, soil, and plants, the slope terrain was analyzed according to topographic feature. In addition, in consideration of changes in setting location that might affect the measured result, this study reviewed the accuracy of measured data obtained from different measurement areas.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.177-186
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• 2021

For disaster management and mitigation of earthquakes in Korea Peninsula, active fault investigation has been conducted for the past 5 years. In particular, investigation of sediment-covered active faults integrates geomorphological analysis on airborne LiDAR data, surface geological survey, and geophysical exploration, and unearths subsurface active faults by trench survey. However, the fault traces revealed by trench surveys are only available for investigation during a limited time and restored to the previous condition. Thus, the geological data describing the fault trench sites remain as the qualitative data in terms of research articles and reports. To extend the limitations due to temporal nature of geological studies, we utilized a terrestrial LiDAR to produce 3D point clouds for the fault trench sites and restored them in a digital space. The terrestrial LiDAR scanning was conducted at two trench sites located near the Yangsan Fault and acquired amplitude and reflectance from the surveyed area as well as color information by combining photogrammetry with the LiDAR system. The scanned data were merged to form the 3D point clouds having the average geometric error of 0.003 m, which exhibited the sufficient accuracy to restore the details of the surveyed trench sites. However, we found more post-processing on the scanned data would be necessary because the amplitudes and reflectances of the point clouds varied depending on the scan positions and the colors of the trench surfaces were captured differently depending on the light exposures available at the time. Such point clouds are pretty large in size and visualized through a limited set of softwares, which limits data sharing among researchers. As an alternative, we suggested Potree, an open-source web-based platform, to visualize the point clouds of the trench sites. In this study, as a result, we identified that terrestrial LiDAR data can be practical to increase reproducibility of geological field studies and easily accessible by researchers and students in Earth Sciences.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.179-186
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• 2010

In this research, an effective method for absolute positioning of feature points is proposed, which is applicable to geo-referencing of terrestrial LiDAR data scanned in dense urban areas. GPS positioning, common in absolute positioning, is apt to fail in the presence of signal disturbancein dense urban circumstances, while traditional surveying methods, including traversing and leveling, are generally more costly for wider areas. The idea is that reference points, marked on top of buildings, are surveyed by GPS positioning and then feature points are relatively positioned from the reference points. The present method, if laser scanning is accompanied, gets two advantages; one is that less feature points need to be surveyed because they can be substituredby reference points, and the other is that laser scanning can be more stably carried out. The present method was shown, from the experiments, to be cost-effective against traditional ones.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.127-136
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• 2015

This study aims to quantify the stand-level above ground biomass in intact tropical rain forest of Brunei using airborne LiDAR data. Twenty four sub-plots with the size of 0.09ha ($30m{\times}30m$) were located in the 25ha study area along the altitudinal gradients. Field investigated data (Diameter at Breast Height (DBH) and individual tree position data) in sub-plots were used. Digital Surface Model (DSM), Digital Terrain Model (DTM) and Canopy Height Model (CHM) were constructed using airborne LiDAR data. CHM was divided into 24 sub-plots and 12 LiDAR height metrics were built. Multiple regression equation between the variables extracted from the LiDAR data and biomass calculated by using a allometric equation was derived. Stand-level biomass estimated from LiDAR data were distributed from 155.81 Mg/ha to 597.21 Mg/ha with the mean value of 366.48 Mg/ha. R-square value of the verification analysis was 0.84.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.323-328
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• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.

• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.123-128
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• 2004

최근 디지털 카메라(Digital camera), 다중/고분광 영상(Mumltispectral/Hyperspectral image), LiDAR(Light Detection and Ranging), InSAR(Interferometric SAR)와 같이 지상을 보다 상세하고 높은 정확도로 지상을 매핑할 수 있는 센서들이 출현하고 있다. 이러한 다양한 정보 취득 자료를 충분히 활용하여 통합하기 위해서는 영상에 대하여 정확한 기하보정 또는 정사영상의 제작과 LiDAR 자료와 같은 경우 평면위치의 오차를 조정하여 다중자료들 간의 정확한 지형보정(Coregistration)이 필요하다. 본 연구에서는 AIR-MS 자료를 이용하여 즉, 항공기로부터 취득한 LiDAR(Height와 강도(Intensity) 자료), digital camera을 통합하고, 기존의 컬러항공사진 및 1:1000 수치지도를 이용하여 3D GIS 자료의 생성을 시도하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.327-327
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• 2017

최근 지구 온난화에 따른 기후변화로 인한 해수면 상승과 폭풍해일의 강도 및 발생빈도가 증가하고 고파랑 내습, 난개발 등으로 인한 연안 지역의 해안선 변화 및 연안 침식이 크게 문제화되고 있다. 연안 환경의 변화를 분석하는 방법에는 광파측거기를 이용한 해빈 측량, RTK-GPS를 이용한 측정, 항공사진 분석 등이 주된 연구 방법이지만 이러한 연구 방법으로는 미세한 지형 변화의 관찰은 어려움이 많았으며 세밀하고 정량적인 지형분석이 요구 되었다. 본 연구에서는 연구대상지역인 가곡천 하구부를 대상으로 지상 LiDAR를 이용해 장기간 정밀측량을 실시하였다. 자료를 바탕으로 가곡천 하구부의 부피와 면적을 비교분석하였으며, 해안선변화의 정량적 비교분석을 실시하였다.

• Economic and Environmental Geology
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• v.52 no.3
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• pp.231-241
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• 2019

Kinematic analysis determines the stability of rock slope by analyzing the relationship between the slope face orientation and the discontinuity orientation. In this study, terrestrial LiDAR was used to obtain a large amount of discontinuity orientation data and then, the probabilistic characteristics of the orientation data obtained using terrestrial LiDAR were analyzed. Subsequently, the probabilistic kinematic analysis was carried out using the discontinuity orientations generated randomly from Fisher function in Monte Carlo simulation. In addition, the probabilistic kinematic analysis was also performed using the actual orientation data obtained from the terrestrial LiDAR to compare their results. Consequently, the results of both probabilistic analyses showed similar results. Therefore, if sufficient orientation data are provided by other means such as terrestrial LiDAR, the probabilistic analysis will show reasonable results using the actual field data without randomly generating orientation data. In addition, the deterministic kinematic analysis was also carried out using representative orientation of discontinuity sets. The analysis result of the probabilistic analysis showed similar results with the deterministic analysis because the dispersion of the discontinuity orientations in a joint set is not large.