• Korean Journal of Geomatics
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• v.5 no.1
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• pp.7-19
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• 2005

Photogrammetric mapping procedures have gone through major developments due to significant improvements in its underlying technologies. The availability of GPS/INS systems greatly assist in direct geo-referencing of the acquired imagery. Still, photogrammetric datasets taken without the aid of positioning and navigation systems need control information for the purpose of surface reconstruction. Point features were, and still are, the primary source of control for the photogrammetric triangulation although other higher-order features are available and can be used. LIDAR systems supply dense geometric surface information in the form of three dimensional coordinates with respect to certain reference system. Considering the accuracy improvement of LIDAR systems in the recent years, LIDAR data is considered a viable supply of photogrammetric control. To exploit LIDAR data, new challenges are poised concerning the representation and reference system by which both the photogrammetric and LIDAR datasets are described. In this paper, registration methodologies will be devised for the purpose of integrating the LIDAR data into the photogrammetric triangulation. Such registration methodologies have to deal with three issues: registration primitives, transformation parameters, and similarity measures. Two methodologies will be introduced that utilize straight-line and areal features derived from both datasets as the registration primitives. The first methodology directly incorporates the LIDAR lines as control information in the photogrammetric triangulation, while in the second methodology, LIDAR patches are used to produce and align the photogrammetric model. Also, camera self-calibration experiments were conducted on simulated and real data to test the feasibility of using LIDAR patches for this purpose.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.4
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• pp.79-87
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• 2008

There has been a strong demand for low altitude UAV development in rapid mapping not only to acquire high resolution image with much more low cost and weather independent, compared to satellite surveying or traditional aerial surveying, but also to meet many needs of the aerial photogrammetry. Especially, efficient geocoding of UAV imagery is the key issue. Contrary to high UAV potential for civilian applications, the technology development in photogrammetry for example direct georeferencing is in the early stage and it requires further research and additional technical development. In this study, two approaches are supposed for automatic geocoding of UAV still images by simple affine transformation and block adjustment of affine transformation using minimal ground control points and also evaluated the applicability and quality of geometric model compared to geocoded images generated by commercial S/W.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.4
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• pp.211-218
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• 2019

The Ministry of Land, Infrastructure and Transport is planning to launch CAS-500 (Compact Advanced Satellite 500) 1 and 2 in 2019 and 2020. Satellite image information collected through CAS-500 can be used in various fields such as global environmental monitoring, topographic map production, analysis for disaster prevention. In order to utilize in various fields like this, it is important to get the location accuracy of the satellite image. In order to establish the precise geometry of the satellite image, it is necessary to establish a precise sensor model using the GCP (Ground Control Point). In order to utilize various fields, step - by - step automation for orthoimage construction is required. To do this, a database of satellite image GCP chip should be structured systematically. Therefore, in this study, we will analyze various techniques for automatic GCP extraction for precise geometry of satellite images.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.179-188
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• 2021

Biodiversity informatics applies information technology methods in organizing, accessing, visualizing, and analyzing primary biodiversity data and quantitative data management through the scientific names of accepted names and synonyms. We reviewed the GBIF data published by China, Japan, Taiwan, and internal institutes, such as NIBR, NIE, and KNA of the Republic of Korea, and assessed data in diverse aspects of data quality using BRAHMS software. Most data from four Asian countries have quality problems with the lack of data consistency and missing information on georeferenced data, collectors, collection date, and place names (gazetteers) or other invalid data forms. The major problem is that biodiversity management institutions in East Asia are using unstructured databases and simple spreadsheet-type data. Owing to the nature of the biodiversity information, if data relationships are not structured, it would be impossible to secure the data integrity of scientific names, human names, geographical names, literature, and ecological information. For data quality, it is essential to build data integrity for database management and training systems for taxonomists who are continuous data managers to correct errors. Thus, publishers in East Asia play an essential role not only in using specialized software to manage biodiversity data but also in developing structured databases and ensuring their integration and value within biodiversity publishing platforms.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.945-954
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• 2019

Cultural property is a valuable asset that connects the past with the present, and cultural heritage is now included in the international agenda of disaster risk reduction. Accordingly, the importance of building resilience of cultural assets has been on the rise, and the necessity of spatial information has been emphasized in building resilience. Therefore, in this study, A methodology for studying the resilience contained in cultural assets through linkage with historical map and time series spatial information is proposed and the proposed methodology was applied to cultural assets located in Gongju area. Georeferencing was performed on time-series images of aerial images and topographical map, and the changes in cultural assets and surrounding areas were found. The width of the river has changed due to the installation of the Keum River Estuary Dam and the dammed pool for irrigation. Nevertheless, the main cultural assets and monuments are located in the high-altitude area and thus have been well preserved. In this study, cultural property resilience was extracted using only map data and in future, it is necessary to conduct research to extract cultural property resilience through analysis of historical records such as geography.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.1
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• pp.19-27
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• 2019

This study is to measure the length of the Demilitarized Zone and the Military Demarcation Line(MDL) on the Korean Peninsular. For this purpose, maps of the Armistice Agreement Volume II were used. These maps are nine sheets. In order to extract the MDL shown on the map, coordinates were assigned to the scanned image maps using the georeferencing module of ArcGIS based on the sheet line coordinates. The accuracy of the extracted vectors was checked by overlaying them on the maps of the Armistice Agreement Volume II. And I tried to validate these vectors through comparative analysis with vectors extracted from Kim(2007). Vectors extracted from Kim(2007) had errors in the curvilinear parts of the MDL, but the vectors extracted from this study exactly matched the MDL in the Armistice Agreement Volume II. The measured length is 239.42km(148.77miles). This means that the expression '155mile MDL' or '248km DMZ' in papers, reports or mass media has so far been inappropriate. I think this study will be able to provide information on the exact length of the DMZ in studies related with DMZ or in policy decisions by the national and local government. However, it is deemed necessary to verify this result by national organizations such as the NGII(National Geographic Information Institute). After these verification procedures, I hope that the national government will inform the people of the exact length of DMZ and MDL.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.1
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• pp.19-28
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• 2019

Images captured by drone have the advantage of quickly constructing spatial information in small areas and are applied to fields that require quick decision making. If an image registration technique that can automatically register the drone image on the ortho-image with the ground coordinate system is applied, it can be used for various analyses. In this study, a methodology for geo-referencing of a single image and sequential images using drones was proposed even if they differ in spatio-temporal resolution using linear features and distinct points. Through the method using linear features, projective transformation parameters for the initial geo-referencing between images were determined, and then finally the geo-referencing of the image was performed through the template matching for distinct points that can be extracted from the images. Experimental results showed that the accuracy of the geo-referencing was high in an area where relief displacement of the terrain was not large. On the other hand, there were some errors in the quantitative aspect of the area where the change of the terrain was large. However, it was considered that the results of geo-referencing of the sequential images could be fully utilized for the qualitative analysis.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.59-66
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• 2007

The digital working environment and its related technology have been rapidly expanding. In the surveying field, we have changed from using optical film cameras and plotters to digital cameras, multi sensors like GPS/INS etc,. The old analog work flow is replaced by a new digital work flow. Accurate data of the land is used in various fields, efficient utilization and management of land, urban planning, disaster and environment management. It is important because it is an essential infrastructure. For this study, LiDAR surveying was used to get points clouds in the study area. It has a high vegetation penetrating advantage and we used a digital process from planning to the final products. Contour lines were made from LiDAR data and compared with national digital base maps (scale 1/1,000 and 1/5,000). As a result, the accuracy and the economical efficiency were evaluated. The accuracy of LiDAR contour data was average $0.089m{\pm}0.062\;m$ and showed high ground detail in complex areas. Compared with 1/1,000 scale contour line production when surveying an area over $100\;km^2$, approximately 48% of the cost was reduced. Therefore we prepose LiDAR surveying as an alternative to modify and update national base maps.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.379-388
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• 2012

The Road Name Address system has begun to be applied and widely used since 2011. However, the Digital Map, or the national representative basic map, has no reference to the Road Name Address system. It causes some difficulties to use the Digital Map under the Road Name Address system. In this paper, we suggest a method for generating the expanded Digital Map by adding information about Road Name Address system into the objects of the Digital Map. First, object matching pairs between the road section layer from the Road Name Address Map and the road centerline layer from the Digital Map are found. Then attributes to be copied from the Road Name Address map to the Digital Map are extracted by comparing their attribute tables. Finally the extracted attributes are copied from the Road Name Address Map to the Digital Map. The expanded road centerline layer of the Digital Map then has attributes about road name according to the Road Name Address system, so that the georeferencing of the Digital Map according to the Road Name Address system becomes possible.

• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.407-418
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• 2018

The frequency and risk of disasters are increasing due to environmental and social factors. In order to respond effectively to disasters that occur unexpectedly, it is very important to quickly obtain up-to-date information about target area. It is possible to intuitively judge the situation about the area through the image-map generated at high speed, so that it can cope with disaster quickly and effectively. In this study, we propose an image-map generation and visualization system from UAV images for real-time disaster monitoring. The proposed system consists of aerial segment and ground segment. In the aerial segment, the UAV system acquires the sensory data from digital camera and GPS/IMU sensor. Communication module transmits it to the ground server in real time. In the ground segment, the transmitted sensor data are processed to generate image-maps and the image-maps are visualized on the geo-portal. We conducted experiment to check the accuracy of the image-map using the system. Check points were obtained through ground survey in the data acquisition area. When calculating the difference between adjacent image maps, the relative accuracy was 1.58 m. We confirmed the absolute accuracy of the image map for the position measured from the individual image map. It is confirmed that the map is matched to the existing map with an absolute accuracy of 0.75 m. We confirmed the processing time of each step until the visualization of the image-map. When the image-map was generated with GSD 10 cm, it took 1.67 seconds to visualize. It is expected that the proposed system can be applied to real - time monitoring for disaster response.