• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.3
• /
• pp.267-275
• /
• 2007

Nowadays, it grows bigger the importance of water resource management, and so, hydrographic surveying technology in river is important because it serves basic data about river environment. And, also, the application field of GPS has been increased and expected to be more increased because of the change of the geodetic reference system to World Geodetic System. In this study, hydrographic surveying in Hwang river in Geochang is accomplished by RTK GPS and Total Station and they are compared and analyzed the both results. The section profile in river is made by Hec-Ras program and CAD. The results show it can be saved 15.3% in surveying times and the amount of surveying works can be enlarged 42.5%. And the standard error between RTK results with calibration and the results without calibration turned out as 2.1 cm. So we have a conclusion that RTK GPS is more efficient surveying method than total station in hydrographic surveying in river.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.39 no.4
• /
• pp.235-243
• /
• 2021

River surveying is conducted to acquire basic geographic data for river master plans and various river maintenance, and it is also used to predict changes after river maintenance construction. ABL (Airborne Bathymetric LiDAR) system is a cutting-edge surveying technology that can simultaneously observe the water surface and river bed using a green laser, and has many advantages in river surveying. In order to use the ABL data for river surveying, it is prerequisite step to segment and extract the water surface and river bed points from the original point cloud data. In this study, point cloud segmentation was performed by applying the ground filtering technique, ATIN (Adaptive Triangular Irregular Network) to the ABL data and then, the water surface and riverbed point clouds were extracted sequentially. In the Gokgyocheon river area, Chungcheongnam-do, the experiment was conducted with the dataset obtained using the Leica Chiroptera 4X sensor. As a result of the study, the overall classification accuracy for the water surface and riverbed was 88.8%, and the Kappa coefficient was 0.825, confirming that the ABL data can be effectively used for river surveying.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.1
• /
• pp.61-67
• /
• 2021

With the recent development of bathemetry technology, the hydrographic surveying method has been changed from single beam depth device use to multi beam acoustic sounding technology. Also, various studies have been reported to obtain high accuracy and precision in the process of river bed topographic data. Especially south korea is geographically on three sides of the sea and the river topography is very developed. To build information about the underwater, and riverbed status, the public investigations has been continuously progressed. In this study, We investigasted the riverbed topography near Baeckma river leisure park. for this purpose, In this study, as the first preliminary survey, location of navigational dangerous objects and reefs and the dangerous areas are identified. Also, ground control points is selected for the optimal GPS surveying. Secondary, through test surveying the Gain, TVG, and pulse length are determined. In addition, the investigation of dangerous objects for navigation is also conducted. As the last step, the error analysis are conducted for the acquired data, and this process involves the removal and adjustments of errors. This section includes the analysis of tide level and navigational contributions, and finally generates a submarine topographic map.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.185-185
• /
• 2011

Mapping of artificial levee lines, one of major tasks in river zone mapping, is critical to prevention of river flood, protection of environments and eco systems in river zones. Thus, mapping of artificial levee lines is essential for management and development of river zones. Coastal mapping including river zone mapping has been historically carried out using surveying technologies. Photogrammetry, one of the surveying technologies, is recently used technology for national river zone mapping in Korea. Airborne laser scanning has been used in most advanced countries for coastal mapping due to its ability to penetrate shallow water and its high vertical accuracy. Due to these advantages, use of LiDAR data in coastal mapping is efficient for monitoring and predicting significant topographic change in river zones. This paper introduces a method for construction of a 3D artificial levee line using a set of LiDAR points that uses normal vectors. Multiple steps are involved in this method. First, a 2.5-dimensional Delaunay triangle mesh is generated based on three nearest-neighbor points in the LiDAR data. Second, a median filtering is applied to minimize noise. Third, edge selection algorithms are applied to extract break edges from a Delaunay triangle mesh using two normal vectors. In this research, two methods for edge selection algorithms using hypothesis testing are used to extract break edges. Fourth, intersection edges which are extracted using both methods at the same range are selected as the intersection edge group. Fifth, among intersection edge group, some linear feature edges which are not suitable to compose a levee line are removed as much as possible considering vertical distance, slope and connectivity of an edge. Sixth, with all line segments which are suitable to constitute a levee line, one river levee line segment is connected to another river levee line segment with the end points of both river levee line segments located nearest horizontally and vertically to each other. After linkage of all the river levee line segments, the initial river levee line is generated. Since the initial river levee line consists of the LiDAR points, the pattern of the initial river levee line is being zigzag along the river levee. Thus, for the last step, a algorithm for smoothing the initial river levee line is applied to fit the initial river levee line into the reference line, and the final 3D river levee line is constructed. After the algorithm is completed, the proposed algorithm is applied to construct the 3D river levee line in Zng-San levee nearby Ham-Ahn Bo in Nak-Dong river. Statistical results show that the constructed river levee line generated using a proposed method has high accuracy in comparison to the ground truth. This paper shows that use of LiDAR data for construction of the 3D river levee line for river zone mapping is useful and efficient; and, as a result, it can be replaced with ground surveying method for construction of the 3D river levee line.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.5
• /
• pp.592-597
• /
• 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 Forest and Environmental Science
• /
• v.13 no.1
• /
• pp.81-89
• /
• 1997

Urban river needs continuous observation for the river conservation because river surrounding environment sensitivly is changed by human activity. In order to grasp the effect of human activity against Taebaek river in Chunchon city, this research analysed the channel shape change, fluctuation volume and bias degree over five times, for June, 1993 to June, 1996. The results were as follows : 1. The change of channel shape on each surveying time mainly occurred in June, 1996 and maximum deposition. $1,247m^3$ occurred on 19~20 section, maximum scouring, $340m^3$ occurred on 6~7 section, 2. When comparing with June, 1993, increased deposition volume of channelbed was about $4,600m^3$ in June, 1996, 3. The bias degree of channel mainly occurred in June, 1996 of surveying times and at 6, 7, 15, 16, 17, 18, 19, 20 line of surveying lines.

• Journal of Korean Society for Geospatial Information Science
• /
• v.22 no.2
• /
• pp.25-32
• /
• 2014

The river plan executes the role for prevention of disaster and protection of environment, and requires the surveying results with high accuracies for managing river, dam, reservoir which will be the major infrastructures. The purpose of this study is for comparing and analyzing the results of river surveying which is used widely for disaster management and construction industry support. The results are gathered by using LiDAR which is being used in Korea recently and by using Total station. Study area is chosen at upper area of Bukhan River which is located at Gangwon-do. Total 2 cross-sections of the two methods are extracted from the study area. The standard deviation of land part is about 0.017m which shows little difference between two methods, but the Airborne LiDAR results cannot survey the heights of the points accurately at the singular points with vertical structure and water body part. To overcome the problems through this study, there should be ways to survey the bottom river through transmission of water level within the same margin scope as land part and to survey detailed facilities used by laser exactly through continuous research and experiment. When implementation stage comes, this study expect that this document will be utilized variously for making decision in the area of planning and drawing of business and engineering not just for river regarding the major area or the area that people cannot access.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.38 no.2
• /
• pp.87-95
• /
• 2020

South korea has been developing and managing the complete dimensions, around the rivers to rapid economic growth. In Korea, where water resources are scarce, administration and work are complicated and diversified in the computerization of related facilities and hydrologic data due to the indiscriminate development of river facilities. In general, dividing the water system based on object in remote sensing is relatively accurate in the image with the same spectral characteristics. However, the distinction between the reservoir and the river must be made manually due to the characteristics of remote sensing. Therefore, this study performed three classifications using GIS (Geographic Information System) to classify reservoirs and rivers. For the purpose of accuracy analysis, the land cover map provided by EGIS (Environmental Geographic Information Service) was used to evaluate the accuracy, and the average of 85.63% was found to be 75.40% of rivers, 89.50% of reservoirs, and 92.00% of others.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2009.04a
• /
• pp.19-21
• /
• 2009

Updating in Digital Map 2.0 using as-built drawings required for correcting spatial conflicts due to data acquired at different time. In this paper, we defined the type of spatial conflicts and logical expression between river and contours.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.47-50
• /
• 1999

From 1997 irrigation water withdraws has been surveyed for the purpose of river operation and management . Recently , the River Law was revised (1999.2.8) and obligate to water users to report their proposed and actual water withdrawals. If we can save more water from rice paddy area, we can use more water for municipal and industrial activity and we can expect water quality should be improved in the river. So the role of irrigation water use efficiency is more and more important.