• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.139-150
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• 2023

Terretial LiDAR surveying is highly useful for maintenance of civil facilities as it can easily detect the temporal deformation of structures or topography. However, for river facilities such as levess, it is difficult to detect the deformation of the topography or structure under vegetations due to the influence of vegetation. Vegetation filters can be divided into color filters and morphological filters. In this study, combined filters with color and morphology are developed to improve the accuracy of vegetation filters. 8 color filters, 6 morphological filters, and 4 combined filters are applied to the vegetation removal on the embankment slope, and their accuracy and calculation time are compared. Color filters show a short calculation time, but the accuracy was low in the vegetation area. Morphological filters show high accuracy in the vegetation area, but low accuracy in places with severe local topographical changes such as heavy rocks. Combined filters also show a tendency similar to morphological filters, but in the case of ExGGM, the accuracy is excellent in both the vegetation and rock area. Considering the accuracy and calculation time, the combined filter ExGGM is suitable for general cases, and the shape filter GrMIn or the complex filter ExGISL is suitable for cases where the local topographical change is not severe.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.1
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• pp.10-18
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• 2017

Korean Red Pine (Pinus densiflora) has been protected and used as the most ecologically and socio-culturally important tree species in Korea. However, as dieback of Korean red pines has occurred in the protected area of the forest genetic resources. The aims of this study is to identify causes for dieback of pine tree by investigating topographical characteristics of pine tree dieback and its correlation to meteorological factors. We extracted the dead trees from the time series aerial images and analyzed geomorphological characteristics of dead tree concentration area. As a result, 1,956 dead pine trees were extracted in the study region of 2,600 ha. Dieback of pine trees was found mostly in the areas with high altitude, high solar radiation, low topographic wetness index, south and south-west slopes, ridgelines, and high wind exposure compared to other living pine forest area. These areas are classified as high temperature and high drought stress regions due to micro-climatic characteristics affected by topographic factors. As high temperature and drought stress are generally increasing with climate change, we can evaluated that a risk of pine tree dieback is also increasing. Based on these geomorphological characteristics, we developed a pine tree dieback risk map using Maximum Entropy Model (MaxEnt), and it can be useful for establishing Korean red pine protection and management strategies.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.259-272
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• 2022

Background: The Korean Peninsula exhibits a characteristic graded floral distribution, with northern (Manchurian flora) and southern (China-Japan-Korea flora) lineage species coexisting according to climatic and topographical characteristics. However, this distribution has been altered by climate change. To identify ecosystem changes caused by climate change and develop appropriate measures, the current ecological status of the entire Korean Peninsula should first be determined; however, analysis of the current floral distribution in North Korea has been hampered for political reasons. To overcome these limitations, this study constructed a database of floral distributions in both South and North Korea by integrating spatial information from the previously established National Ecological Survey in South Korea and geocoding data from the literature on biological distributions published in North Korea. It was then applied to analyze the current status and distribution characteristics of Manchurian and China-Japan-Korea plant species on the Korean Peninsula. Results: In total, 45,877 cases were included in the Manchurian and China-Japan-Korea floral distribution database. China-Japan-Korea species were densely distributed on Jeju-do and along the southern coast of the Korean Peninsula. The distribution density decreased as the latitude increased, and the distributions reached higher-latitude regions in the coastal areas compared with the inland regions. Manchurian species were distributed throughout North Korea, while they were densely distributed in the refugia formed in the high-elevation mountain regions and the Baekdudaegan in South Korea. In the current distribution of biomes classified according to the Whittaker method, subtropical and endemic species were densely distributed in temperate seasonal forest and woodland/shrubland biomes, whereas boreal species were densely distributed in the boreal forest biome Korean Peninsula, with a characteristic gradation of certain species distributed in the temperate seasonal forest biome. Factor analysis showed that temperature and latitude were the main factors influencing the distribution of flora on the Korean Peninsula. Conclusions: The findings reported herein on the current floral distribution trends across the entire Korean Peninsula will prove valuable got mitigating the ecological disturbances caused by ongoing climate change. Additionally, the gathered flora data will serve as a basis for various follow-up studies on climate change.

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.188-200
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• 2000

On the basis of the Landsat TM scenes with 15 year's time differences, the topographic maps with 50 years differences, and the air photos with 25 years differences, we carried out the field survey for geology and forestry and analyzed the topographical change and the variation of the forest resource in Anmyundo. In terms of the discrimination of forest trees in Anmyumdo, the NDVI with larger than 0.5 in the winter season is the indicator of the surface of the pine tree land-cover. The peak values of NDVI appear on the surface of the pine aging 30 through 50 years and decrease a little and grossly stabilized over the more aging trees. The distinction of the deciduous forest and grass land from the pine tree was capable with the correlation with the abrupt seasonal variation of NDVI and the surface aspect. The great change of topography is detected in the region Changgiri due to the continuous tidal erosion since the canal construction about 370 years ago and along the all around coast of Anmyundo due to the reclamation for the paddy field. The surface area of the pine tree land-cover in Anmyundo was estimated 35.91 km$^2$ in 1986 and 33.15 km$^2$ in 1993, which is originated from the grassland development in the southeastern part of Anmyundo where the pine tree dominated by 1986. In the northen part of Anmyundo the surface area of the pine land-cover increased a little in 1993 comparing to 1986.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.64-73
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• 2010

This research collected some multi-image information of Nakdong River Estuary Eulsukdo area in last 30 years, which are used as the basis information in running the qualitative analysis of the topography relief's deformation. First, to obtain the data, this research carried out a field survey and GCP measurement, then classified and collected the image information by analog and digital image. The acquired images which have passed a high-precise scan process and geometric correction is manufactured by Ortho Mosaic image, then divided them into 9 sections time period classification before we run a qualitative analysis. In late of 1980's there are many changes of environmental topography deformation of the Eulsukdo area which caused by large scale building constructions, appeared to be known through this research. And then in late of 1990's, we organized the wild cultivated lands, started the wetland restoration of the artificial ecology, in 2000's we are able to know the existence of topograph relief change which caused by big scale of bridge construction. Hereafter, in this quick process of the environmental and topographical change of this area caused by the 4 major rivers restoration project, the analysis results of this experiment are expected to be something applicable as important basic data.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1164-1172
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• 2012

This study aims to make a "farmland use map" using high-resolution images and to analyze the land use change for about 8 years in Goyang, Namyangju, and Yongin cities. We have made a new numerical map named as a farmland use map using high-resolution images taken mostly in 2007 and digital topographical maps in Goyang, Namyangju, and Yongin cities near metropolitan areas to classify farmland use of paddy, upland, plastic film house, and orchard. We also made a land use map by overlaying the farmland use map and the land registration map of each city made in 2007, and compared the land use map made by RDA (Rural Development Administration) in 1999. Paddy areas decreased at a range of 3,000 to 5,000 ha during 8 years and were changed to residential areas in the cities. Upland and orchard areas also showed similar tendency and were changed to residential areas as well. On the other hand, the areas of the plastic film houses in the cities showed an increase or same in size. It is suggested that farmland use map can be broadly used as a base map for various survey projects including soil survey, statistics, and farmland information management.

• Journal of the Korean association of regional geographers
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• v.15 no.2
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• pp.282-291
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• 2009

This research predicts the spatial discord which relates with a restriction using 1915 and 2005 spatial data. In this research, difference of relative spatial density is measured and predicted the discord which relates with an environmental restriction in Pyeongchang. First, research area Pyeonchang's relative crowding degree of the building was strengthened from 1915 to 2005. When classifies a change type, formed the strong hold with new regulation and grew types and at the strong hold where contiguous concentration is progress types, general the influence weakening types and the change almost nil types. The next is the result which analyzes the long and short terms discord for the environmental restriction which is forecast from the research area. That is forecast with the fact that the discord between of development and preservation will be big with long and short terms in Jinbu-Myeon, Pyeongchang-Eup city center angles and 31 national road circumferences. And in Daegwanryeong-Myeon the discord is big short-term but with the fact that the discord will be weakened long-term. Bangrim-Myeon, now the discord is weak but the discord will be strengthened long-term. This result could be applied with fundamental data for weakening the spatial discord of the area.

• Journal of Korea Water Resources Association
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• v.42 no.5
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• pp.397-406
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• 2009

River is able to change by various environmental factors. In order to conduct restoration design of abandoned river channels, it is necessary to evaluate the river through the analysis of past and present river channels. River evaluation requires various data, such as geometry, hydraulic and hydrology, but there is a lot of difficulty to understand topographical information of river change on time and space due to a lack of past data by domestic conditions. This study analyzes the changes in past and present river channels and examines the applicability of river channel evaluation through image analysis using aerial photographs and 1918 year's map. Aerial photograph analysis was conducted by applying the image analysis method and GIS analysis method on Cheongmicheon. As a result of this analysis, we have quantitatively identified the form and size of abandoned channels, changes in the vertical-section and cross-section length of rivers, and micro-landform changes. More importantly, we verified that morphological changes in sandbars due to artificial straightening are important data in identifying the state of current river channels. In these results, although image analysis technique has limitations in two-dimensional information from aerial photographs, we were able to evaluate the changes in river channel morphology after artificial maintenance of the river.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.99-112
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• 2021

This study was performed to predict spatial change of future forestland area in South Korea at regional level for supporting forest-related plans established by local governments. In the study, land use was classified to three types which are forestland, agricultural land, and urban and other lands. A logistic regression model was developed using transitional interaction between each land use type and topographical factors, land use restriction factors, socioeconomic indices, and development infrastructures. In this model, change probability from a target land use type to other land use types was estimated using raster dataset(30m×30m) for each variable. With priority order map based on the probability of land use change, the total annual amount of land use change was allocated to the cells in the order of the highest transition potential for the spatial analysis. In results, it was found that slope degree and slope standard value by the local government were the main factors affecting the probability of change from forestland to urban and other land. Also, forestland was more likely to change to urban and other land in the conditions of a more gentle slope, lower slope criterion allowed to developed, and higher land price and population density. Consequently, it was predicted that forestland area would decrease by 2027 due to the change from forestland to urban and others, especially in metropolitan and major cities, and that forestland area would increase between 2028 and 2050 in the most local provincial cities except Seoul, Gyeonggi-do, and Jeju Island due to locality extinction with decline in population. Thus, local government is required to set an adequate forestland use criterion for balanced development, reasonable use and conservation, and to establish the regional forest strategies and policies considering the future land use change trends.

• Journal of the Korean association of regional geographers
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• v.14 no.1
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• pp.27-39
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• 2008

The propose of this research paper is to clarify the formative process of the lake-like swamps formed in channels of Nakdong-gang river and its tributary, Gumho-gang river. In order to understand the formative process of lake-like swamps, I compared topographical maps of three years(1918, 1962, 2005), analyzed the outline change of swamps, and draw their cross-sectional view and analyzed the horizontal distribution of particle size. Results of analysis are as follow. First, Saegang swamp and Geumgang swamps are residual swamps which are formed in abandoned distributary channels of braided reach. In braided reach, tributaries wind freely to create a new channel or to eliminate a old channel. Second, the Ssiksil swamp and Nat swamp are yazoo-type swamps. Their stream channels run parallel to the natural levees, as it blocks the waterway of a effluent tributary flowing from backward mountains to main stream. Third, the Secheon, Hochon and Jinchon swamps are backswamp behind natural levee. As main stream overflows, natural levee and back swamp are formed. Later flowing water of next bigger flood enter through natural levee into backswamp, create a channel following backswamp.