• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.74-88
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• 2010

In this study, the points of LiDAR were modified in order to generate various DEM resolutions by applying LiDAR data in Ulsan. Since the LiDAR data have points with 1m intervals, the number of points for each resolution was modified to the size of 1, 5, 10, 30, 50, 100m by uniformly eliminating the points. A runoff analysis was performed on Taehwa river and its tributary, Dongcheon, with 200 year rainfall exceedance probability. 2-dimensional inundation analysis was performed based on the density of LiDAR data using FLUMEN, which was used to establish domestic flood risk map. Once DEM data obtained from LiDAR survey are used, it is expected that the study results can be used as data in determining optimal grid spacing, which is economical, effective and accurate in establishing flood defence plans including the creation of flood risk map.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.203-210
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• 2004

A new research of geographic information system has been focused on an open architecture, interoperability and extensibility in their design. In order to process huge data, multidimensional data and heterogeneous geographic format data, these research move away from monolithic system to open structure system managing application layer and user interface layer. Nowadays, many developers have used CORBA middleware for the OGIS systems. However, CORBA middleware has some problems that support only a point-to-point communication and takes a long time to transfer sever data to client. Thus, in this paper, we propose a method on modifying a point-to-point communication and implement the efficient communication method. The proposed method that transfer data from sever to client in one connection support a group communication and reduce a transfer time delay.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.71-80
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• 1999

The aim of the present study is to define and tentatively to interpret the distribution of polluted water released from Lake Sihwa into the Yellow Sea using Landsat TM. Since the region is an extreme Case 2 water, empirical algorithms for detecting concentration of chlorophyll-a and suspended sediments have limitations. This work focuses on the use of multi-temporal Landsat TM data. We applied PCA to detect evolution of spatial feature of polluted water after release from the lake Sihwa. The PCA results were compared with in situ data, such as chlorophyll-a, suspended sediments, Secchi disk depth(SDD), surface temperature, remote sensing reflectance at six channel of SeaWiFS. Also, the in situ remote sensing reflectance obtained by PRR-600(Profiling Reflectance Radiometer) was compared with PCA results of Landsat TM data sets to find good correlation between first Principal Component and Secchi disk depth($R^2$=0.7631), although other variables did not result in such a good correlation. Therefore, Problems in applying PCA techniques to multi-spectral remotely sensed data were also discussed in this paper.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.22-34
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• 2007

The purpose of this study is to assess agricultural drought using modified SWSI(Surface Water Supply Index) in Ango and Anseo agricultural district. Precipitation, reservoir inflow and storage data were used for input data of modified SWSI. Precipitation data was obtained from KMA(Korea Meteorological Administration) and reservoir storage data was obtained from KARICO(Korea Agricultural & Rural Infrastructure Corporation) and reservoir inflow data was simulated by SLURP(Simple LUmped Reservoir Parametric). SWSI based agricultural drought index was evaluated for the period of 1983 and 2001. As results, for the drought periods(July-1994, June-1995, May-2001) agricultural drought indices represented extremely drought states. The result was compared with PDSI and SWSI and checked the applicability of the suggested index in our agricultural drought situation.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.1
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• pp.59-66
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• 2013

When the typhoons are passing over the ocean, the ocean environment has both physical and biological impacts on the East, South sea and Yellow sea of Korea. As a result of typhoon path, vertical mixing and upwelling injured colder subsurface water, and leaded to phytoplankton blooming along the typhoons. The ocean environment before and after a typhoon played an important role in the biological effect of sea surface. Although the magnitude of sea surface temperature (SST) gets cooler because of typhoon path, other physical and biophysical responses are quite different such as chlorophyll, K490 and SST. The purpose of this study is to compare with the typhoon path that influenced the Korean Peninsula and ocean environment parameters which were observed by ocean color remotely-sensed data. The MODIS data were used to assess the parameters of ocean environments such as K490 and chlorophyll data from 2002 to 2005. Mean chlorophyll from MODIS data increased by about 1-4% in the East sea after the typhoon. Mean concentration of MODIS chlorophyll in the post-typhoon period increased along the typhoon passage. However, Jeju coastal area has different patterns from those of the East sea.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.1-14
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• 2004

In this study, we propose Linktable based on extended TB-Tree(LTB-Tree) which can improve the performance of existing TB (Trajectory-Bundle)-tree proposed for indexing the trajectory of moving objects in GIS Applications. In addition, in order to evaluate proposed indexing scheme, we take into account as follows. At first, we select existing R*-tree, TB-tree, and LTB-tree as the subject of performance evaluation. Secondly, we make use of random data set and real data set as experimental data. Thirdly, we evaluate the performance with respect to the variation of size of memory buffer by considering the restriction of available memory of a given system. Fourth, we test them by using the experimental data set with a variation of data distribution. Finally, we think over insertion and retrieval performance of trajectory query and range query as experimental measures. The experimental results show that the proposed indexing scheme, LTB-tree, gains better performance than traditional other schemes with respect to the insertion and retrieval of trajectory query.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.383-388
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• 2006

Most of GIS services have been operated in single applications, and as data processing and computer and mobile technologies have developed rapidly, users request for efficient sharing between each GIS's own data and various different GIS's. However, since many GIS applications maintain their own data formats, they are incapable of processing data formats different with each other, and do not have a filtering function for mobile GIS. This paper designs an integrated preprocessor, SMP to accept features of various current formats of geographic information such as DXF(Drawing eXchange Format), DWG(DraWinG), SHP(SHaPefile), etc., and to extract core information for describing maps. The geographic information extracted by SMP(Synthetic Map Preprocessor) shows consistency in various formats by visualizing through the integrated view. By generating the extracted core data in GML, it supports rapid access to mobile devices and extensibility of file formats overcoming heterogeneity.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.136-147
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• 2021

Autonomous driving-related technologies are developing step by step by applying the degree of driving. It is essential that operational management technology for roads where autonomous vehicles move should also develop in line with autonomous driving technology. However, in the case of road operation management, it is currently managed using only two-dimensional information, showing limitations in the systematic operation management of lane and facility information and maintenance. This study proposed a plan to construct an operation management system architecture capable of 3D spatial information-based operation management by designing a convergence database that can process real-time big data with high-definition road map data. Through this study, when using a high-definition road map based operation management system for lane and facility maintenance in the future, it is possible to visualize and manage facilities, edit and analyze data of multiple users, link various GIS S/W and efficiently process large scale of real-time data.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.705-708
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• 2005

Mobile Mapping Systems using the vehicle equipped the GPS, IMU, CCD Cameras is the effective system for the management of the road facilities, update of the digital map, and etc. They must provide users with the sensor data which is acquired by Mobile Mapping Systems in real-time so that users can process what they want by using the latest data. But it' s not an easy process because the amount of sensor data is very large, particularly image data to be transmitted. So it is necessary to reduce the amount of image data so that it is transmitted effectively. In this study, the effective method was suggested for the compression/decompression image data using the Wavelet Transformation and Huffman Coding. This technique will be possible to transmit of the geographic information effectively such as position data, attitude data, and image data acquired by Mobile Mapping Systems in the wireless internet environment when data is transmitted in real-time.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.676-678
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• 2003

Recently, in according as rapid improvement of telecommunication markets and wireless internet technology, Location- Based Services (LBS) have been discussed as new 'Killer' application. The purpose of LBS is to determine location of user through mobile handset and to offer location information service to end-user. This paper has suggested an efficient transmission scheme of maps data as one of the important content services relating to data transmission of LBS in mobile environment. The basic system consists of three parts : (1) GIS (Geographic Information System) Server for storing, processing and handling map data, (2) Middleware Server for transmitting of map data by request of client, and (3) Client for requesting map data to Server and displaying them on handset. Also, in order to transmit map data, we are to expand WKB (Well Known Binary) in conformance to Simple Feature Specification of OGC (Open GIS Consortium), and increase efficiency of data transmission by developing trans mission data format to be able to transmit lightweight data and considering data compression technology.