• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.32 no.6
• /
• pp.625-635
• /
• 2014

Multiple strips are required for large area mapping using ALS (Airborne Laser Scanner) system. LiDAR (Light Detection And Ranging) data collected from the ALS system has discrepancies between strips due to systematic errors of on-board laser scanner and GPS/INS, inaccurate processing of the system calibration as well as boresight misalignments. Such discrepancies deteriorate the overall geometric quality of the end products such as DEM (Digital Elevation Model), building models, and digital maps. Therefore, strip adjustment for minimizing discrepancies between overlapping strips is one of the most essential tasks to create seamless point cloud data. This study implemented area-based matching (ABM) to determine conjugate features for computing 3D transformation parameters. ABM is a well-known method and easily implemented for this purpose. It is obvious that the exact same LiDAR points do not exist in the overlapping strips. Therefore, the term "conjugate point" means that the location of occurring maximum similarity within the overlapping strips. Coordinates of the conjugate locations were determined with sub-pixel accuracy. The major drawbacks of the ABM are sensitive to scale change and rotation. However, there is almost no scale change and the rotation angles are quite small between adjacent strips to apply AMB. Experimental results from this study using both simulated and real datasets demonstrate validity of the proposed scheme.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.301-306
• /
• 2010

Recently GIS is not only displaying and servicing data on the 2D, but also is changing rapidly to display and service 3D data. Also 3D related technology is developing actively. For display of 3D data, terrain DTM has become a basis. Generally, to acquire DTM, users are using LIDAR data or digital map's contour line. However, if using these data for producing DTM, users need to additional cost and data lead time. And hard to update terrain data. For possibility of solving these problem, this study did DTM extraction with automatic matching for aerial photograph, and analysed the result with measurement of Orthometric height and excuted accuracy through DTM(which extracted from digital photogrammetric technique). As a result, we can get a high accuracy of RMSE (0.215m).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.34 no.1
• /
• pp.71-78
• /
• 2016

In the paper, we predict the number of multi-GNSS satellites and visible satellites with the navigation satellite launch plans and their nominal orbit parameters. Based on the methodology, the multi-GNSS navigation performance and DOP (Dilution of Precision) variation from 2015 to 2020 were forecasted by the Matlab simulation. To calculate the position using the multi-GNSS constellation, we determined the time-offset between the two different systems. Two different algorithms were considered for the sake of time-offset determination; that of each was applied to system level and user side. Also, the results from two algorithms were compared for evaluating each performance. For the reality, we applied the 3D map information to the simulation, which is expected to contribute for predicting the future navigation performance in urban canyon.

• Journal of Korean Society for Geospatial Information Science
• /
• v.11 no.2 s.25
• /
• pp.39-45
• /
• 2003

Roads have been developed throughout the history of mankind, and play a significant role among many traffic facilities for the economy, politics and cultures of our lives. However, the management of roads has not been fully scientific or systematic due to governmental policies focused on construction resulting in damages, and the loss of drawings for existing roads. In this case, it is difficult to manage roads using normal cadastre due to its time consuming work. And, when applying satellite surveying to rapidly extract the centerline of roads, it is impossible to obtain data about the status of internal tunnels. Therefore, this study can be used to extract optimum alignment data of tunnels using the data from satellite surveying, and is a practical paper which can contribute to efficient management and usage of alignment data and road facilities in establishing a HMS(Highway Management System) for the renewal and management of the alignment data of roads, by comparing the data from satellites with the alignment data in existing drawings.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.26 no.6
• /
• pp.591-598
• /
• 2008

Recently, the government has improvement projects of dangerous road for the site that has very high accident rate due to bad geometric structures of the road. Although, route selecting of the road is a basic and important process, but the process of route selecting must consider the technical, safety and environment factor together. Also, the technology for the 3-dimensional terrain model can be used as an important factor in planning and designing for selecting alternative route projects. In the course of experimenting with the 3-dimensional topography generated by the combination of the digital map and drawing of route, the technology as been developed to offer the multi-dimensional access to the potential construction sites from the nearby main roads. This 3-dimensional digital elevation model has made it possible to make various terrain analysis base on GIS, which provides real-time virtual access to the designated construction sites for development planning and construction projects. Therefore, this study presents a reasonable plan for route selecting from some alternative routes through subjective evaluation and classify the methods linked basic design of road construction.

• Korean Journal of Remote Sensing
• /
• v.24 no.2
• /
• pp.153-164
• /
• 2008

According to the economic growth, many highways are constructed for increasing need of better life style. Especially roads and roadside facilities are used for accident prevention and offering mobility for drivers. For these purpose, roads and roadside facilities should be well maintained and managed. Now, many roads and roadside facilities are constructed in many areas. Because of traditional surveying method requires much time and surveying efforts, we designed and developed mobile mapping system for highway maintenance and management purpose using multi sensors. We tested our mobile mapping system and data management process. Using developed database, road managers can easily check the information of facility conditions, positions, and attributes. We are expecting low cost and efficient road maintenance process by using our system.

• Korean Journal of Remote Sensing
• /
• v.33 no.6_1
• /
• pp.971-980
• /
• 2017

In this research, it was presented that the strategic approach for the long-term shoreline changes using historic digital aerial images can be effective for the analysis on the bangameori beach, west coast of South Korea. For this purpose, we collected several historic digital aerial images over 9 years in the research filed and conducted GPS-VRS surveying for GCP (Ground Control Point) acquisition. Also we collected existing two dimensional shoreline digital map which was published by KHOA (Korea Hydrographic and Oceanographic Agency) in the year 2013. With these multi data sets, we provided quantitative analysis on coastal erosion using the long-term shoreline changes in the beach. Also, As the results it was found that 2m sea level was retreated in the research period with maximum 0.31m length.

• Korean Journal of Geomatics
• /
• v.3 no.2
• /
• pp.81-86
• /
• 2004

In recent years, the importance of geospatial data have been emphasized not only for the national GIS programs and but also in the value added commercial and industry markets. There is no doubt that GIS, GPS, aerial and satellite imagery data were provided powerful tools to support national information infrastructure for geospatial database. While great emphasis has been laid on the geospatial data, there has been little analysis or evaluation of how to maximize the benefits of using these information sources. Also, with the proliferation of geographic data and information sources such as satellite imagery, digital aerial photograph, digital topographic and vector data, there is a great need to inform professionals from all disciplines as to the benefits of these information sources and how to best put them to use within any given application. From the first publication of KSGPC(Korean Society of Geodesy, Photogrammetry and Cartography) papers in 1981, our objective was, and is, to help develop the wider spectrum of GIS in the academy and industry by exposing new users to the benefits of GIS, remote sensing, mapping, GPS and photogrammetry. In this presentation, we will introduce KSGPC works and will evaluate GIS-related governmental policies and programs in Korea for the past and the future to present different status between Korea and Russia. It is now important to investigate lessons learnt from two countries' experiences and developed an empirical framework to combine outcome from GIS-related researches in Korea and Russia. This may enable GIS professionals to gain a wider range of experiences in the international context, and consequently, help them to develop new markets for GIS. Therefore, we arranged the possible action items and interesting points to corporate and to promote the academic growth in the practice of GIS.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.21 no.3
• /
• pp.127-137
• /
• 2018

Recently, UAVs and Drones have been used for various applications. In particular, in the field of surveying, there are studies on the technology for monitoring the terrain based on the high resolution image data obtained by using the UAV-equipped digital camera or various sensors, or for generating high resolution orthoimage, DSM, and DEM. In this study, we analyzed the accuracy of GCP(Ground control point) matching using UAV and VRS-GPS. First, we used VRS-GPS to pre-empt the ground reference point, and then imaged at a base altitude of 150m using UAV. To obtain DSM and orthographic images of 646 images, RMSE was analyzed using pix4d mapper version As a result, even if the number of GCP matches is more than five, the error range of the national basic map(scale : 1/5,000) production work regulations is observed, and it is judged that the digital map revision and gauging work can be utilized sufficiently.

• Journal of Korean Society for Geospatial Information Science
• /
• v.14 no.4 s.38
• /
• pp.27-36
• /
• 2006

Conventionally, in order to get accurate geolocation of satellite images we need a set of ground control points with respect to individual scenes. In this paper, we tested the possibilities of modeling satellite orbits from individual scenes by establishing a sensor model for one scene and by applying the model, which was derived from the same orbital segment, to other scenes that has been acquired from the same orbital segment. We investigated orbit-attitude models with several interpolation methods and with various parameter sets to be adjusted. We used 7 satellite images of SPOT-3 with a length of 420km and ground control points acquired from GPS surveying. Results of the conventional individual scene modeling hardly introduced differences among different interpolation methods and different adjustment parameter sets. As the results of orbit modeling, the best model was the one with Lagrange interpolation for position/velocity and linear interpolation for attitude and with position/angle bias as parameter sets. The best model showed that it is possible to model orbital segments of 420km with ground control points measured within one scene (60km).