• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.497-505
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• 2021

Due to recent underground space accidents, are a frequent occurence in Korea, the government established the basic plan for the construction of the IUGIM (Integrated Underground Geospatial Information Map) in 2015 as a measure for safety management of underground spaces. The development of IUGIM was partially completed as of 2021. The underground space management entity and related organizations are utilizing it. This study is being carried out as part of a plan to improve the usability of IUGIM, and to build a visualization system that compares real-time field data with stored data. A system, equipped with a visualization function for borehole data and 6 types of underground facilities built and managed on IUGIM; a tool capable of comparative analysis with real-time data measured in the field, is being built. The 6 types of underground facilities are water supply pipe, sewage pipe, power pipe, gas pipe, communication pipe, and heating pipe. The completed system was demonstrated at three locations in Seocho-gu, Gangnam-gu in Seoul. The field demonstration was carried out by accessing the mobile center and downloading IUGIM data, visualizing IUGIM data (surface creation, borehole information, underground facilities), and visualizing the GPR(Ground Penetrating Radar)-based data acquired at the field. As a result of the empirical results of IUGIM data and GPR-based field data, it was judged to be suitable. As a result of this study, it is judged that it can be helpful for safe construction at the excavation site.

• 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.38 no.4
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• pp.345-352
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• 2020

To preserve and restore tidal flats and prevent safety accidents, it is necessary to construct tidal flat topographic information including the exact location and shape of tidal creeks. In the tidal flats where the field surveying is difficult to apply, airborne LiDAR surveying can provide accurate terrain data for a wide area. On the other hand, we can economically obtain relatively high-resolution data from UAV (Unmanned Aerial Vehicle) surveying. In this study, we proposed the methodology to generate high-resolution topographic information of tidal flats effectively by integrating airborne LiDAR and UAV point clouds. For the purpose, automatic ICP (Iterative Closest Points) registration between two different datasets was conducted and tidal creeks were extracted by applying CSF (Cloth Simulation Filtering) algorithm. Then, we integrated high-density UAV data for tidal creeks and airborne LiDAR data for flat grounds. DEM (Digital Elevation Model) and tidal flat area and depth were generated from the integrated data to construct high-resolution topographic information for large-scale tidal flat map creation. As a result, UAV data was registered without GCP (Ground Control Point), and integrated data including detailed topographic information of tidal creeks with a relatively small data size was generated.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.401-408
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• 2017

GNSS(Global Navigation Satellite System) is positioning and navigation system using satellites. Accurate positioning is possible in all regions of the world using satellite signals. In Korea, GPS was introduced in the late 1980s. GPS is used in research and work in various fields such as navigation, surveying, and GIS. Since 1995, NGII(National Geographic Information Institute) has installed and operated CORS(Continuously Operating Reference Station) for the practical use of GNSS surveying, RINEX download and VRS(Virtual Reference Station) service was provided for precise positioning. Demand for these services is explosively increasing in the field of surveying. Therefore, there is a need for research to provide good service. In this study, status of national surveying infra structure was researched focused on CORS and its services. As a results, current status of CORS and service were presented. Users of VRS service has increased greatly. In order to provide stable service and advanced surveying, it is necessary to continuously upgrade services such as providing services for various GNSS satellites and securing stability through server redundancy in the data center.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.931-936
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• 2008

Surveying by using terrestrial LiDAR(Light Detection And Ranging) is more rapid than by using total station which enables tunnel section profile surveying to be done in suitable time and minimize centerline error, occurrence of overcut and undercut. Therefore, utilization of terrestrial LiDAR has increased more and more in section profile survey and measurement field Moreover, studies of terrestrial LiDAR for accurate and efficient utilization is now ongoing vigorously. Average end area formula, which was generally used to calculate overcut and undercut, was compared with existing methods such as total station survey and photogrammetry. However, there are no criteria of spacing distance for calculating overcut and undercut through terrestrial LiDAR surveying which can acquire 3D information of whole tunnel. This research performed reverse engineering to decide optimal spacing distance when surveying tunnel section profile by comparing whole tunnel volume and tunnel volume in difference spacing distance. This result was utilized to produce CAD drawing for the test tunnel site where there is no design drawings. In addition to this, efficiency of LiDAR and accuracy of CAD drawing was compared with targetless total station surveying of tunnel section profile. Finally, error analysis of target coordinate's accuracy and incidence angle was done in order to verify the accuracy of terrestrial LiDAR technology.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.131-138
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• 2006

Recently, data gathering and algorithm developing are in progress for the GIS application using point feature. Several researches prove that verification of the spatial clustering and evaluation of inter-dependencies between event and control are possible. On the other hand, most of the point features as GIS data are gathered by indirect method, such as address geo-coding, rather than by direct method, such as field surveying. Futhermore, lots of statistics by administrative district based on the point features have no coordinates information of the points. In this study, calculating the K-index in GIS environment, to evaluate the effect of aggregation of raw data on K-index, K-indices estimated from raw data (parcel unit), topographically aggregated data (block unit), administratively aggregated data (administrative district unit) are compared and evaluated. As a result, point feature, highly clustered in local area, is largely distorted when aggregated administratively. But, the K-indices of topographically aggregated data is very similar to the K-indices of raw data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.401-408
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• 2005

Presently many constructions establish in underwater, but approaching to underwater constructions are difficult, for comparing with ground, underwater environment is different in media. Usually measurement methods for underwater constructions are using tapes, using depth gauges, using acoustic positioning systems. But, tapes are hard to measure the correct distance, for applying a right tension is not easy in underwater. Depth gauges have a weakness in settling, for it takes long time to do it. Acoustic positioning systems don't work well in confined spaces and cost a lot. Hence, the purpose of this study is, at first, to understand rays path in multimedia like water, glass and air. The second thing is to perform a camera calibration at the field to compare with the interior orientation parameter. And the third thing is to find out whether photogrammetry is applied for underwater object in using cube for accuracy examination. The last thing is to perform underwater photogrammetry about underwater object, which is pier model and riverbed. We came to the conclusion through this experiment that the applying underwater photogrammerty for underwater constructions and underwater ground is possible.

• Spatial Information Research
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• v.17 no.1
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• pp.89-102
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• 2009

The information of ocean topology is the fundamental source which is necessary for understanding the ocean, producing nautical charts and delimiting maritime boundaries. An echo sounder is being used generally to collect undersea bathymetric data, but an indirect method such as geophysical data acquired by satellites is being used recently. In this study, the outputs of ocean surveying for the production of the Basic Maps of the Sea in 1996 and 1997 in the East Sea and the bathymetric data produced by geophysical data are compared and analyzed. The study areas are Ulleung Plateau, Ulleung Basin and the southern area of Ulleung Basin which have different geophysical characteristics. Through this study, we found that the bathymetric data acquired by an indirect method using satellite is similar to the field surveying results in general configuration of ocean floor and average depth. However, the minimum square error is about 100m in 1700m depth, and it has been observed a local error up to 1000m. In addition, it has been found that the detailed undulation of ocean topology is shown on the gravity data which is acquired by the research vessel.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.2
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• pp.137-143
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• 2004

The electronic distance measurement(EDM) instrument, introduced first in the 1950s since those early days has, undergone continual refinement. Rapid advances established in related technologies have made it lighter, smaller and more precise equipment. Understanding for the principle, the standardized observation technique and the precision of EDM instrument is mostly important to improve the quality and the reliability of by-product in the field of engineering and industrial surveying. Periodical and accurate calibration is necessary to maintenance the precision of EDM instrument. This paper describes the calculated example of zero error and scale error as a correction of EDM by applying the least square method to baseline observations in test area. Also here we deal with the testing criteria for precision instrument testing according to different types of EDM instruments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.3
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• pp.299-304
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• 2010

Depending on the progress of the surveying and information processing technology, the rapidly developing field of spatial information and the 3D real world spatial information for a variety of content on the computer was able to easily access. In this research, to study on the spot or to use aerial photographs to measure trees of the acquired data, calculate the trees height, forest area and capacity, determine the distribution of the density of acquired points in the forest and analyze accurate and objective information was acquired. The United States, Canada and so on through the capacity of trees biomass, forest resource analysis, time series monitoring, wildfire behavior modeling and applied research and has been declared. During worldwide is increasing interest in forest resources. In nationally, extensive research and analysis of the forest consists of the correct management and protection of forest resources to be effective.