• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.5
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• pp.109-126
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• 2017

Universal soil loss equation (USLE) is used to estimate soil loss solely or employed in any hydrologic models. Since soil erosion has been an issue in South Korea for decades, the Ministry of Environment enacted a law to regulate soil erosion in 2012, which is the Notification of topsoil erosion status. The notification is composed of preliminary and field investigations, the preliminary investigation suggests to use USLE and provides USLE factors. However, the USLE factors provided in the notification was prepared at least 10 years ago, therefore it is limited to reflect recent climate changes. Moreover the current yearly USLE approach does not provide an opportunity to consider seasonal variation of soil erosion in South Korea. A GIS-based model was therefore applied to evaluate the yearly USLE approach in the notification. The GIS-based model employs USLE to estimate soil loss, providing an opportunity to estimate monthly soil loss with monthly USLE factor databases. Soil loss was compared in five watersheds, which were Geumgang, Hangang, Nakdonggang, Seomjingang, and Yeongsangang watersheds. The minimum difference was found at Seomjingang watershed, the yearly potential soil loss were 40.15 Mg/ha/yr by the notification approach and 34.42 Mg/ha/yr by the GIS-based model using monthly approach. And, the maximum difference was found at Nakdonggang watershed, the yearly potential soil loss were 27.01 Mg/ha/yr by the notification approach and 10.67 Mg/ha/yr by the GIS-based model using monthly approach. As a part of the study result, it was found that the potential soil loss can be overestimated in the notification approach.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.1 s.15
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• pp.27-42
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• 2000

In this study, a GIS-supported system is used to measure the effect of social infrastructure improvements. Benefit evaluation approach is based on two types of approaches -the simple hedonic approach and Rosen's two step approach. The land attribute data for both approaches are efficiently collected and generated in a GIS-supported environment. Moreover, it conveys more objective and correct data. The benefits are estimated on real locations by using GIS. The potentiality of the developed system for practical application has been verified by its application to Joban New Line in Tokyo metropolitan area. By incorporating benefit evaluation routines into GIS, the proposed system will be a useful tool for decision making on the improvements of social infrastructure.

• Spatial Information Research
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• v.16 no.4
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• pp.489-497
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• 2008

Currently, GIS has been widely used in the hedonic analyses of urban apartment housing markets in Korea. In those analyses, the apartment complexes are typically represented as the points or the polygons on the GIS maps and the location variables of the analyses are measured based on the points or the polygons. In this study, the relative performance of the point based approach and the polygon based approach in a GIS based hedonic analysis was compared using the apartment housing market data from the north eastern part of the city of Seoul and Davidson and MacKinnon Test. The results from this study indicate two things. First, two approaches can produce substantially different results in a hedonic price model estimation. Second, the polygon based approach produces a hedonic price model which explains the price variations better than the point based approach. These findings suggest that Korean researchers who are interested in improving quality of hedonic price model estimations and use GIS to measure the location variables for hedonic price models should consider using the polygon based approach with the point based approach. This is because the polygon based approach can produce the location variables with the shortest straight line distances and can explain the housing price variations well.

• Korean Journal of Remote Sensing
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• v.3 no.2
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• pp.115-119
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• 1987

After the introduction of the topologically structured geographic information system(GIS) with relational DBMS, the attribute data can be handled without considering locational data. By utilzing of the characteristic of the relational DBMS, it can be used as an expert system building tool in GIS. The relational DBMS of the GIS furnishes the data needed to perform deductive functions of the expert system, and the rule based approach provides the decision rules. Therefore, rule based approach with the expert judgement can be easily combined with relational DBMS.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.3-5
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• 2009

The matching process is not simple, since the identified features from different sources do not always match in their location, extent, and description. We present a new approach to matching GIS features from disparate sources. A graph theoretic approach is used to model the geographic context and to determine the matching features from multiple sources.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.753-758
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• 2005

This study attempts at building an integrated GIS computing framework for evaluating space-time accessibility of an individual with the approach of time geography model. The proposed method is based on the integration of mobile GIS and object-relational spatio-temporal database. Three components are central to our system: ( i ) mobile GIS application that transmits spatio-temporal trajectory data of an individual; ( ii ) spatio-temporal database server that incorporates the time geography model; and (iii) geovisualization client that provides time geographic queries to the spatio-temporal database. As for the mobile GIS application, spatio-temporal trajectory data collected by GPS-PDA client is automatically transmitted to the database server through mobile data management middleware. The spatio-temporal database server implemented by extending a generic DBMS provides spatio-temporal objects, functions and query languages. The geovisualization client illustrates 3D visual results of the queries about space-time path. space-time prism and space-time accessibility. This study shows a method of integrating mobile GIS and DBMS for time geography application, and presents an appropriate spatio-temporal data model for evaluating space-time accessibility of an individual.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.39-44
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• 2003

Recently, GIS has been increasing its applicability in water resource field. The GIS based modeling process can generally be used for extracting channel network and watershed delineation. Through the overlay analysis, the extracted channel network can be overlayed with topographic and landuse maps to generate the input files for running a hydrologic model. This lead to consider GIS as a tool which can include subjective factors of the model designers in hydrologic analysis. Therefore, this study has compared GIS based HEC-GEOHMS with the classical approach. In general, both approaches have similar results, however, HEC-GROHMS has showed some errors. Based on the results, a GIS based approach could be more effective method with better credibility to obtain input parameters from topographic information as subsequent efforts were made to lessen the errors.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.542-542
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• 2002

Geometric correction is a critical step to remove geometric distortions in satellite images. For correct geometric correction, Ground Control Points (GCPs) have to be chosen carefully to guarantee the quality of corrected satellite images. In this paper, we present an automatic approach for geometric correction by constructing GCP Chip database (GCP DB) that is a collection of pieces of images with geometric information. The GCP DB is constructed by exploiting Landsat's nadir-viewing property and the constructed GCP DB is combined with a simple block matching algorithm for efficient GCP matching. This approach reduces time and energy for tedious manual geometric correction and promotes usage of Landsat images.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.107-109
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• 2004

High-resolution remotely sensed data such as SPOT-5 imagery are employed to study the effectiveness of the watershed segmentation algorithm. Existing problems in this approach are identified and appropriate solutions are proposed. As a case study, the panchromatic SPOT-5 image of part of Beijing urban areas has been segmented by using the MATLAB software. In segmentation, the structuring element has been firstly created, then the gaps between objects have been exaggerated and the objects of interest are converted. After that, the intensity valleys have been detected and the watershed segmentation have been conducted. Through this process, the objects in an image are divided into separate objects. Finally, the effectiveness of the watershed segmentation approach for high-resolution imagery has been summarized. The approach to solve the problems such as over-segmentation has been proposed.

• 한국지형공간정보학회:학술대회논문집
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• 2005.08a
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• pp.21-25
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• 2005

A GIS application for assessment of carrying capacity for national parks was developed and presented in this study. Three criteria--ecological factors, facilities, and institutions--were employed as determining factors for assessing the carrying capacity. Using the GIS-based approach, the site-specific carrying capacity for the Chi-Ri National Park was assessed and a carrying capacity map was prepared. This carrying capacity map can be helpful in making policies for decentralizing visitors and keeping the park environmentally stable.