• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.145-157
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• 2018

Mountainous areas are 64% in Korea and are allowed to be used by the permission standards of the "Mountainous Districts Management Act". In the act, slope and elevation criteria are defined to regulate the use of vulnerable land parcels to disaster. However, the standards cannot represent topographical variation in a land parcel such as terrain relief. Therefore, the applicability of slope type standard as a permission standard was tested using Catena in this study. Based on the theoretical grounds, two slope types were analyzed as 'risky slope' with disaster risk. The slope types of landslides in Namwon City were analyzed that 'risky slope' types were distributed about 57%. This study analyzed the forestland parcels that could be used when applying the current permission standards and the parcels that were already used in Namwon City. The ratio of the 'risky slope' in the parcels was more than 50%. Therefore, it is necessary to prevent the mountain development in 'risky slope' by establishing permission standard related to slope types. In addition, this study suggested the ratio of 'risky slope' in the parcel for the permission standard for forestland use conversion.

• Journal of Korean Society of Forest Science
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• v.97 no.6
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• pp.617-626
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• 2008

Recently, it has been issued whether the current permission standards for forest land-use conversion is adequate or not. This study was aimed at evaluating the propriety of the current permission standards using the Delphi technique, which is one of survey techniques regarding experts's opinions. The results of the survey indicated that the standards related to the connection development restriction and the height of the first berm were underrated in most of the evaluation factors. The size limit and the altitude restriction of the land-use conversion also have a low propriety or applicability due to their vagueness. In case of average slope, its applicability was rated as significantly low because there is no standardized method for estimating or verifying the average slope. A statistical analysis based on coefficient of variation and one-way ANOVA were conducted to examine whether each group of experts agree with these survey results. It is appeared that the survey using Delphi technique could successfully achieved an agreement from each group of experts. Overall, evaluation factors considered in this study seems to be effective to verify the problems of each standards and to guide to improvement of the standards.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.59-71
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• 2019

In Mountainous Districts Management Act of Korea Forest Service, slope and elevation criteria are operated to regulate the indiscriminate use of risky land parcels when forestland is converted to other land use types. However, there is a limitation in considering topographical variation with only such two indices in the land parcel. Therefore, in order to supplement insufficient criteria, the slope type standard was developed using Catena, and the ecological condition improved terrain standards. Firstly, the ratio of 'risky slope' in a target forestland parcel was defined to decrease the risk of disasters such as landslides. Secondly, the standard of the ecological location condition was proposed as ecological score by integrating age, diameter and soil depth classes in the target forestland parcels. Thereby, we could prepare reasonable standards that can reduce forestland disasters and ecological damages, as suggesting new topographical and ecological assessment methods for forestland use conversion.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.87-96
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• 2007

In this study, a Ridge Distinction Program was developed to improve the elevation standard, which is one of standards for mountainous districts conversion permission regulated by the Management of Mountainous Districts Act. To distinguish mountainous districts from other land types, this program assumed that the lower end of the mountainous districts is the outlet points where catchment size is 30ha. Also the program used the halfway line between the ridge and the lower end of the mountainous districts to recognize the upper slope areas. To prevent potential errors within the classification process, the areas that were classified as non-mountainous districts by the current forest type map were removed. According to the classification results by using the developed program, the 58% of the mountainous districts ($696,300m^2$) was classified into the upper slope area, while the only 3% of the mountainous districts ($30,956m^2$) were classified by adopting the current standards for the mountainous districts conversion permission. This result shows that the size of the upper slope areas tends to be altered by the standards defining the area. Therefore, for better acceptance of the Ridge Distinction Program in the associated fields, it is necessary to prove the effectiveness of the program and to revise the current standards for the mountainous districts conversion permission.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.3
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• pp.85-92
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• 2016

Slope is one of the most important factor in land development permission standards. In guideline of "Land Suitability Assessment" or "Forest Land Conversion Standard", average slope can be measured using digital map and GIS for target area. Inputs in slope calculation are 1/5,000 digital map of NGII(National Geographic Information Institute) or digital information of Korea Land Information System. Many confusions occur in the field, as there is no standard for slope calculation and are lots of slope calculation methods using contour lines or DEM derived from them. Avoiding these confusions, this study was intended to propose a standardized method for slope calculation and a selection method for a suitable resolution. In this study, using DEM of optimum grid size according to the complexity of topography with finite difference method is suggested as improved slope calculation method, after comparing several representative slope calculation methods.

• Journal of The Geomorphological Association of Korea
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• v.25 no.3
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• pp.1-18
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• 2018

In Korea, 64% of the land is known as mountain area, but the definition and classification standard of mountain are not clear. Demand for utilization and development of mountain area is increasing. In this situation, the unclear definition and scope of the mountain area can lead to the destruction of the mountain and the increase of disasters due to indiscreet permission of forestland use conversion. Therefore, this study analyzed the variables and criteria that can extract the mountain boundaries through the questionnaire survey and the terrain analysis. We developed a mountain boundary extraction algorithm that can classify topographic mountain by using selected variables. As a result, 72.1% of the total land was analyzed as mountain area. For the three catchment areas with different mountain area ratio, we compared the results with the existing data such as forestland map and cadastral map. We confirmed the differences in boundary and distribution of mountain. In a catchment area with predominantly mountainous area, the algorithmbased mountain classification results were judged to be wider than the mountain or forest of the two maps. On the other hand, in the basin where the non-mountainous region predominated, algorithm-based results yielded a lower mountain area ratio than the other two maps. In the two maps, we was able to confirm the distribution of fragmented mountains. However, these areas were classified as non-mountain areas in algorithm-based results. We concluded that this result occurred because of the algorithm, so it is necessary to refine and elaborate the algorithm afterward. Nevertheless, this algorithm can analyze the topographic variables and the optimal value by watershed that can distinguish the mountain area. The results of this study are significant in that the mountain boundaries were extracted considering the characteristics of different mountain topography by region. This study will help establish policies for stable mountain management.