• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.137-143
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• 2014

Recently, as new paradigm for government operation called government 3.0, government is actively operating policy opening and sharing public data. In addition, the Ministry of Land are operating an open platform integrated map service (the VWorld) which provides a variety of video contents such as the country's national spatial information, traffic information and three-dimensional building for the public. According to W3C Foundation's Open Data Status Report(2013), our country has the evaluated results that the part of the government's policy support and planning is good while the part of the data management is vulnerable. So our country needs the quality improvement for the data management. In addition, a digital aerial photograph image data is required to be up-to-date for the three-dimensional spatial object data. In this paper, we present the method for enhancement of the accuracy of vertical position and for maintainment of up-to-date vertical position. Our methods evaluate the data quality and analyze the cause of error of measurement utilizing the national standard quality assessment method. The result of research shows that the accuracy of vertical position is improved if the height of the building captain is adjusted by the quality assessment values and a three-dimensional model has up-to-date data if reconstruction and extension information of construction register is utilized.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.113-119
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• 2014

The positioning accuracy of GNSS surveys deteriorates due to various error factor, and many users sometimes ignore Phase Center Variation (PCV) of antennas. IGS provides an ANTEX file which contains PCV correction information to correct for PCVs. But it is not directly applicable because PCV correction information is provided at 5-degree intervals in the azimuth and elevation directions for the case of receiver antennas, and at 1-degree intervals in the nadir angle for the case of satellite antennas. So, we devised new and optimal ways of interpolating PCV in any desired line of sight to the GNSS satellite. We used spherical harmonics fitting methods in terms of the azimuth and elevation angle for interpolation, and found an optimal degree and order. It is shown that the best accuracy was obtained from the 8 by 8 spherical harmonics. If one requires lower burden on computing resources, the order and degree less than 8 could produce resonable accuracy except for 1st and 5th order.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.39-46
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• 2014

Network RTK positioning, one of GNSS positioning systems, is currently very popular due to its easy operation and low cost. However, the network RTK positioning unquestioningly accepts observation result acquired with an ambiguity fixed-solution regardless of different field conditions and situations, and then it is applied to the practice. This paper, therefore, has investigated the effects of field conditions obtained network RTK survey data for the area with obstacles on the variation of positioning accuracy. Being explained in detail, after conducting survey by GPS-only positioning and combined GPS/GLONASS observations giving changes to the distance from obstacles and elevation angles, and then accuracy results of each positioning method were compared each other. As a result, while GPS-only point positioning method showed more stable results than combined GPS/GLONASS method in the areas with no obstacles, combined method gave better result than GPS-only for the areas with presence of obstacles. Based on the results of this experiment, when the further study is conducted with a variety of different field conditions affecting the survey accuracy, it can be expected that the accuracy of network RTK survey method would become to more popular.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.21-30
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• 2014

Waste landfill site which is the facility usually rejected by communities is generally perceived as one of the serious social problems. It causes serious conflicts between interested parties from the beginning of the site selection process and produces various difficulties throughout the installation process. This study suggests the systematization and standardization of the landfill site selection process to reduce those problems and to objectify the process. The study process and results are as follows. First, the landfill site selection process was divided into 4 general phases rather than more specific fragmented phases and the requirements for each phase were suggested accordingly. This can make the process clearly organized and bring the standardization of the process by increasing the applicability of each phase for various situations. Second, the utilization of GIS(Geographic Information System) and PAPRIKA (Potentially All Pairwise RanKings of all possible Alternatives) among the various MCDA(Multi-Criteria Decision Analysis) methods was suggested as the objective and scientific method. Third, the hypothetical case study on the landfill site selection process of Cheongju city was conducted based on the information above and the results show the practicability and objectivity of the newly defined landfill site selection process in this study.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.27-38
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• 2015

In this study, the 3D position coordinates were calculated for the targets using DLT and self-calibration bundle adjustment with additional parameters in close-range photogrammetry. And then, the accuracy of the results were analysed. For this purpose, the results of camera calibration and orientation parameters were calculated for each images by performing reference surveying using total station though the composition of experimental conditions attached numerous targets. To analyze the accuracy, 3D position coordinates were calculated for targets that has been identically selected and compared with the reference coordinates obtained from a total station. For the image coordinate measurement of the stereo images, we performed the ellipse fitting procedure for measuring the center point of the circular target. And then, the results were utilized for the image coordinate for targets. As a results from experiments, position coordinates calculated by the stereo images-based photogrammetry have resulted out the deviation of less than an average 4mm within the maximum error range of less than about 1cm. From this result, it is expected that the stereo images-based photogrammetry would be used to field of various close-range photogrammetry required for precise accuracy.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.17-26
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• 2015

River corridors facilitate dispersal and movement and prevent local extinction of species. As a result of stream restoration projects, which include installation of waterfront and flood control structures, the number of animals, which rely on river corridor, is decreasing. For the study, factors affecting fish assembly were extracted by a species distribution model with the fish data collected from the Seom River in Hoengseong County and City of Wonju, Ganwon Province, Korea between March to October 2013. The riparian connectivity was assessed using species richness and rarity. According to result of the field survey, there were 38 species and 7,061 individuals for fish. The analysis suggests the following. Firstly, factors affecting fish richness in species distribution model results are shown to be velocity, riffle, riparian width, and water width. The accuracy of the model proves to be suitable with the correlation coefficient of 0.83 and MAPE of 19.2%. Secondly, the low rarity area is shown to be straight streams in Jeon river near to Hongseong County and the high rarity area to be streams with large width, existing alluvial area at channel junction between Jeon river and Seom river. Thirdly, according to connectivity results, areas where weirs are installed or riparian buffer area is removed showed low connectivity. The areas where farmland near riparian and forest areas showed high connectivity. The results of this study can be utilized to improve current facilities and enhance connectivity as a restoration guide.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.1
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• pp.105-113
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• 2011

Since existing thematic maps have been made with medium- to low-resolution satellite images, they have several shortcomings including low positional accuracy and low precision of presented thematic information. Digital aerial photo image taken recently can express panchromatic and color bands as well as NIR (Near Infrared) bands which can be used in interpreting forest areas. High resolution images are also available, so it would be possible to conduct precision land cover classification. In this context, this paper implemented object-based land cover classification by using digital aerial photos with 0.12m GSD (Ground Sample Distance) resolution and IKONOS satellite images with 1m GSD resolution, both of which were taken on the same area, and also executed qualitative analysis with ortho images and existing land cover maps to check the possibility of object-based land cover classification using digital aerial photos and to present usability of digital aerial photos. Also, the accuracy of such classification was analyzed by generating TTA(Training and Test Area) masks and also analyzed their accuracy through comparison of classified areas using screen digitizing. The result showed that it was possible to make a land cover map with digital aerial photos, which allows more detailed classification compared to satellite images.

• Journal of Korean Society for Geospatial Information Science
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• v.1 no.1 s.1
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• pp.127-140
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• 1993

The purpose of this paper is to examine the possible benefits of combining transportation planning models with geographic information systems (GIS) in the hope that intergrating these systems can alleviate the inherent problems of transportation planning models such as user unfriendliness, labor intensiveness, and theoretical limitations. Specially, this paper focuses on the issue of incompatiblity between GIS and the conventional transportation planning models in dealing with network topologies. Resolving this conflict in topologies is a conerstone for eliminating the user-unfriendliness and labor-intensiveness issues. This paper presents the development of an algorithm that converts GIS topology into transportation network topology. The FORTRAN-based topology conversion algorithm generates transportation networks from the GIS cartographic file and establishes a communication charmel between the two systems.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.1 s.9
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• pp.147-157
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• 1997

A national program for GIS Training had been established by a feasibility study which was performed during the period of from July, 1995 through April, 1996 initiated by Ministry of Science and Technology (MOST). Systems Engineering Research Institute (SERI), one of government-supported institutes in the fields of software development, have taken in charge of Korean GIS training program with emphases on short courses since July, 1996. To distinguish these national programs from those of major commercial GIS software vendor, GIS training programs by executing staffs within SERE have been established with the basis of its own educational paradigm; therefore, they was composed of several specific training curricular developed by executing staffs. In this paper, the practical aspects during execution and progress of these programs are described, and all courses named after decision maker course, GIS manager course, and user course in the first year of GIS training program are evaluated with questionnaire result riven to the trainees. As results, the satisfaction-rate after the decision maker, the GIS manager, and the user course is 84.8%, 81.2%, and 66.7% respectively These whole results are shown as more affirmative ones than expected, and each result, as a kind of feedback of this executing program, plays an important role to flourish Korean GIS training project in future.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.2 s.25
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• pp.17-28
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• 2003

Since 1970s, Seoul Metropolitan Area has been growing in physical and demographic aspect. A number of new urban fringes, New City, had been particularly developed from the early of 1990s. To examine the urban growth, the population density maps are generally used to the efficient urban management tool. The density maps from political boundaries, however, were traditionally used to estimate an urban concentration, there is problems to apply directly to urban management decision making due to (i) the abrupt changes between boundaries and (ii) the inclusion of green areas and forests in these areas. The mass-preserving interpolation method, the Pycnophylactic interpolation, could provide more realistic density maps. In addition, the classified urban areas from satellite images corresponding years would turn out to be more reliable results since populations were only applied to urbanized areas. Even though the Pyconophylactic method makes the density larger, it would be useful to produce a general urban growth trend at large scale. Consequently, four different density maps are compared and reviewed for this study, and the cross-sectional analysis provided to glimpse of population density around the city center.