• Journal of Korean Society for Geospatial Information Science
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• v.24 no.3
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• pp.49-58
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• 2016

Applications of drone in various fields have been increasing in recent years. Drone has great potential for forest management. Therefore this paper is using drone for forest damage areas. Forest damage areas is divided into caused by anthropogenic and occurs naturally, the possibility of disasters, such as slope sliding, slope failures and landslides, sediment runoff exists. Therefore, this research was to utilize the drone photogrammetry to perform the damage analysis of forest damage areas. Geometrical treatment processing results in Drone Photogrammetry, the plane position error RMSE was ${\pm}0.034m$, the elevation error RMSE was ${\pm}0.017m$. The plane position error of orthophoto RMSE was ${\pm}0.083m$, the elevation error of digital elevation model RMSE was ${\pm}0.085m$. In addition, It was possible to current state analysis of damage in forest damage areas of airborne LiDAR data of before forest damage and drone photogrammetry data of after forest damage. and application of drone photogrammetry for production base data for restoration and design in forest damage areas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1942-1948
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• 2021

The cadastre in Korea was established with the outdated technology of the Japanese colonial period, and thus currently 15% of the Korea domestic land does not match the cadastral map. Accordingly, the government has been establishing the Korean cadastre under the name of 'Cadastral Re-investigation Project' and is changing the origin of the survey to the world geodetic system. Assuming that the project is completed, we propose a drone boundary survey method that can be used to easily survey using the exact digital cadastral information. The developed mobile GCS application can control the drone and acquire the boundary point coordinates recorded in the cadastre, and the drone automatically flies to mark the boundary points. The developed prototype of drone made a tour along the 6 boundary points in 2 minutes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.592-597
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• 2020

Currently, river survey data is mainly performed by acquiring longitudinal and cross-sectional data of rivers using total stations or the GNSS(Global Navigation Satellite System). There is not much research that addresses the use of LiDAR(Light Detection and Ranging)systems for surveying rivers. This study evaluates the applicability of using LiDAR data for surveying rivers The Ministry of Land, Infrastructure and Transport recently launched a drone-based river fluctuation survey. Pilot survey projects were conducted in major rivers nationwide. Studies related to river surveying were performed using the ground LiDAR(Light Detection And Ranging)system.Accuracy was ensured by extracting the linearity of the object and comparing it with the total station survey performance. Data on trees and other features were extracted to generate three-dimensional geospatial information for the point-cloud data on the ground.Deviations were 0.008~0.048m. and compared with the results of surveying GNSS and the use of drone LiDAR data. Drone LiDAR provided accurate three-dimensional spatial information on the entire target area. It was able to reduce the shaded area caused by the lack of surveying results of the target area. Analyses such as those of area and slope of the target sites are possible. Uses of drones may therefore be anticipated for terrain analyses in the future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.3
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• pp.162-168
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• 2017

Shallow-water bathymetry survey has been conducted using high definition color images obtained at the altitude of 100 m above sea level using a drone. Shallow-water bathymetry data are one of the most important input data for the research of beach erosion problems. Especially, accurate bathymetry data within closure depth are critically important, because most of the interesting phenomena occur in the surf zone. However, it is extremely difficult to obtain accurate bathymetry data due to wave-induced currents and breaking waves in this region. Therefore, optical remote sensing technique using a small drone is considered to be attractive alternative. This paper presents the potential utilization of image processing algorithms using multi-variable linear regression applied to red, green, blue and grey band images for estimating shallow water depth using a drone with HD camera. Optical remote sensing analysis conducted at Wolpo beach showed promising results. Estimated water depths within 5 m showed correlation coefficient of 0.99 and maximum error of 0.2 m compared with water depth surveyed through manual as well as ship-board echo-sounder measurements.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.117-118
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• 2018

드론의 활용은 점점 더 다양해지며 소규모지역에 대한 정밀 지도제작방법으로 자리매김하고 있다. 그러나, 결과물의 요구정확도의 예측이 불가능하므로 종종 촬영계획을 수정하여 재촬영할 경우가 종종있다. 촬영지역의 면적, 기준점 수 및 배치, 촬영고도 및 중복도에 대한 다양한 정확도 분석이 이루어진다면 사전 시뮬레이션을 통하여 원하는 정확도의 결과물을 얻을 수 있다. 본 연구에서는 드론측량 시 정확도에 영향을 주는 다양한 요소들을 추출하고 정확도 분석을 위한 테스트필드를 설계하고자 한다.

• Journal of Korea Water Resources Association
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• v.55 no.2
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• pp.135-145
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• 2022

This study aims to verify the Drone utilization and the accuracy of the global navigation satellite system (GNSS), Drone RGB (Photogrammetry) (D-RGB), and Drone LiDAR (D-LiDAR) surveying performance in the downstream reaches of the local stream. The results of the measurement of Ground Control Point (GCP) and Check Point (CP) coordinates confirmed the excellence. This study was carried out by comparing GNSS, D-RGB, and D-LiDAR with the values which the hydraulic characteristics calculated using HEC-RAS model. The accuracy of three survey methods was compared in the area of the study which is the ownership station, to 6 GCP and 3 CP were installed. The comparison results showed that the D-LiDAR survey was excellent. The 100-year frequency design flood discharge was applied in the channel sections of the small stream. As a result of D-RGB surveying 2.30 m and D-LiDAR 1.80 m in the average bed elevation, and D-RGB surveying 4.73 m and D-LiDAR 4.25 m in the average flood condition. It is recommended that the performance of D-LiDAR surveying is efficient method and useful as the surveying technique of the geospatial information using the drone equipment in stream channel.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.191-196
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• 2019

The development of open-pit mines leads to large-area topographical changes in highland forests and can lead to severe deterioration of forests, requiring continuous monitoring. The drone photogrammetry is performed at a lower altitude than the existing manned aerial photogrammetry, and thus has a relatively high accuracy. The purpose of this study is to construct spatial information of large open pit mine using drone photogrammetry and to evaluate the accuracy and utilization of the results. The accuracy of the drone photogrammetric results was 0.018 ~ 0.063m in the horizontal direction and 0.027m ~ 0.088m in the vertical direction. These results satisfy the permissible accuracy of 1: 1,000 digital topographic map and it can be used for open mine monitoring. The geospatial information of the open pit mine can be used in various ways, and it can be used to monitor the quantitative change of a specific area for time series change through data management by periodic data acquisition. If drone photogrammetry is applied to open-pit mine monitoring in the future, work time and cost can be greatly reduced compared to the conventional GNSS or total station method, and the work efficiency can be greatly improved because more visible data can be generated.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.79-95
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• 2021

This study evaluates the applicability of determining cadastral surveying results using drone photogrammetry during the phase of determining cadastral surveying results, which is the most important stage of cadastral surveying, but known to be hardly objective and highly probable in causing a subjective misjudgment or mistake made by a surveyor. In the experiment to analyze the accuracy of boundary point extraction from drone photogrammetry results, by comparing the coordinate area of 22 parcels extracted from 2D and 3D images with the coordinate area measured from ground survey, the difference could be quantified as RMSE of 1.44m² for 2D and 0.32m² for 3D images. In addition, experiments to evaluate the determination of cadastral surveying result based on drone photogrammetry survey showed the RMSE measure of 0.346m towards N direction and 0.296m towards Y direction in comparison to the existing surveying results through data investigation. Based on these experiments, it is judged that cadastral surveying result based on drone photogrammetry can be determined without needing to conduct a location survey with an accuracy of approximately 0.3m in the graphical area, which also leads to possibility of reducing individual errors if drones images are used along with ground survey by objectifying the process of cadastral surveying results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.3
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• pp.195-202
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• 2017

Ortho images created by aerial photogrammetry have been used in large areas but they are uneconomical for small areas and continuous change observation. The drones have been developed for military purposes, and recently they are being used crop management and analysis, broadcast relay, meteorological observation and disaster investigation and so on. Also there were a lot of studies of expensive commercial drone. In this paper, lower price self-assembly drone usable for in small areas, Obtained images and produced Orthomosaic and DSM using mission planner which is a normal digital camera and open source program, and postprocessing was used Pix4d software. GCP errors are X-coordinate 3.4cm, Y-coordinate 2.4cm, Z-coordinate 4.2cm. It seems like the self-assembly drone can be used for various fields.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.401-408
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• 2021

With the proposal of amendments to the Pedestrian Safety Act in 2021, when the amendment bill is passed in the near future, a general dimensional investigation of the sidewalks' physical condition, which is the basis of pedestrian safety, is expected to be legislated and made mandatory. Therefore, this study presented a affordable methodology for street environment survey using entry-level drones and examined the feasibility of conducting a complete survey of pedestrian paths by local governments nationwide. To this end, various street facilities in the experimental site were measured to compare and analyze the accuracy of the point cloud data. As a result of the analysis, it was found that the measurement error range satisfies the public surveying guidelines. If the methodology presented in this study is applied, it is expected that individual local governments will be able to make a significant contribution to monitoring the physical conditions of streets to improve the pedestrian environment in the near future.