• Title/Summary/Keyword: Topographic Analysis

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Analysis for Forest Fire Damage Severity Map in Cheongyang

  • Jung Tae-Woong;Yoon Bo-Yeol;Yoo Jae-Wook;Kim Choen
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.537-540
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    • 2004
  • Space-borne multi-sensor data could provide fire scar and bum severity mapping. This paper will present detail mapping of burnt areas in Cheongyange Yesan of Korea with ETM+ image. Burn severity map based on ETM+ image was found to be affected by strong topographic illumination effects in mountainous forest area. Topographic effect is a factor which causes errors in classification of high spatial resolution image like IKONOS image. Minnaert constants J( in each band of ETM+ image is derived for reduction of mountainous terrain effects. Finally, this paper computes quantitative analysis of forest fire damage by each forest types.

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A Study on the Construction Method of the Zone-Based Land Use Information System using Digital Topographic Maps - The Case of the City of Pohang - (수치지형도를 활용한 계획분석구역별 토지이용 정보시스템 구축방안 - 포항시 사례지역을 중심으로 -)

  • Koo, Ja-Hoon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.3 no.3
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    • pp.77-89
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    • 2000
  • The purpose of this study is to establish a Zone-Based Land Use Information System(ZBLIS) using digital topographic maps and public statistics data with a case for Pohang. The Basic Spatial Units(BSUs) used in ZBLIS is the administrative district units(Dong and Lie), and larger or smaller spatial units than this are brought out from BSUs. In the first step, the structure of ZBLIS is constructed to choose Analysis Zone on the top menu, and in subsequent steps, to choose Analysis Categories on sub-menu in terms of dialog windows, and then to choose Analysis Sub-categories and Analysis Theme. The 11 Analysis Categories are consisted of Population, Land Use, Transportation, Industry and Economy etc.. In this case study, it is found that there occur some technical problems in the process of making base-map from digital topographic maps, and inputting attribute data to this base map. For each of these problems, some handling method are recommended.

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Analysis the Impact of Topographic Factors on the Structure of Forest Vegetation in Deogyusan National Park (덕유산 국립공원 산림식생구조의 지형적 영향 분석)

  • Kim, Tae-Geun;Noh, Il;Jeong, Jong-Chul;Cho, Young-Hwan;Oh, Jang-Geun
    • Korean Journal of Ecology and Environment
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    • v.46 no.1
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    • pp.53-59
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    • 2013
  • The purpose of this study was to analyze the topographic effect of the LAI (Leaf Area Index), which has been widely used as an index that quantifies the structure of forest vegetation in Deogyusan National Park. With this aim, the study was conducted through a regression analysis which took as explanation the following variables: the elevation, slope, aspect, and soil moisture conditions. The LAI was taken as the response variable. Overall, the correlation between the Field-LAI and topographic factors was less than 0.5, which was relatively low. Except for topographic altitude, there was no statistical significance regarding the correlation with other factors. Meanwhile, regarding the orientation of the correlation, the higher the attitude, the steeper slope, the lower the soil moist, the lower the LAI value. The topographic altitude was found as a statistically significant explanation variable. The TWI (Topographic Wetness Index), which was used in this study to explain the soil moisture conditions, was not significantly related to the LAI distribution. The results of this study are expected to be utilized as basic data in more accurate forecasting the LAI distribution using remote sensing data.

Topographic Variability during Typhoon Events in Udo Rhodoliths Beach, Jeju Island, South Korea (제주 우도 홍조단괴해빈의 태풍 시기 지형변화)

  • Yoon, Woo-Seok;Yoon, Seok-Hoon;Moon, Jae-Hong;Hong, Ji-Seok
    • Ocean and Polar Research
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    • v.43 no.4
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    • pp.307-320
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    • 2021
  • Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

Investigation and Analysis of Ground Deformation at a Coal Waste Depot in Dogye (도계 석탄폐석 적치장 주변지반의 지형변화 조사 및 분석)

  • Cho, Yong-Chan;Song, Young-Suk;Kim, Kyeong-Su
    • The Journal of Engineering Geology
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    • v.21 no.3
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    • pp.199-212
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    • 2011
  • To investigate the causes of ground deformation around the Dogye coal waste depot in Samcheok city, Gangwon Province, we undertook a field survey and performed boring tests and a topographic analysis using maps compiled in various years. The results of boring tests and analyses of ground fractures indicate that the thickness of the soil layer ranges from 9 to 28.5 m and that ground deformation has occurred to the $240{\sim}250^{\circ}$ direction. The topographic analysis revealed that the topography of the site has changed continuously due to the dumping of coal waste. The causes of ground deformation, investigated by both field surveys and the topographic analysis, were the thick layer of soil at this site, the loading weight of coal waste, and the excavation at the lower part of the slope.

Comparative Analysis of Terrain Slope Using Digital Map, LiDAR Data (수치지형도와 LiDAR 데이터를 이용한 지형경사도 비교분석)

  • Kang, Joon-Mook;Yoon, Hee-Cheon;Min, Kwan-Sik;Rhee, Won-Yong
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.4
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    • pp.3-9
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    • 2007
  • Recently, the efforts of systematic understanding and utilization of geographic phenomenon for human life as a important factor among activity of mankind are increasing. It is necessary to express topography connected with space. Especially, the technology of geographic analysis using DEM can supply the information rapidly and accurately about elevation and terrain slope of the subject area under the necessity of high 3D quality geographic information. In this study, creating more precise DEM derived from LiDAR data, quantitative analysis on the subject area about elevation and terrain slope is done under comparison with Digital Topographic map Scale 1:1000. LiDAR data is more detailed than Digital Topographic map to express the elevation of the subject area ($39.89{\sim}77.48m$), and terrain slope by analysis using DEM derived from LiDAR data come out minutely about 90%. It can be concluded that the LiDAR data is very applicable and accurate for 3D topographic terrain slope analysis.

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Rainfall Adjustment on Duration and Topographic Elevation (지속시간 및 표고에 따른 강우량 보정에 관한 연구)

  • Um, Myoung-Jin;Cho, Won-Cheol;Rim, Hae-Wook
    • Journal of Korea Water Resources Association
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    • v.40 no.7
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    • pp.511-521
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    • 2007
  • The objective of this study is to develop a method of rainfall adjustment on duration and topographic elevation for rainfall data in Jejudo. The method of rainfall adjustment is based on the polynomial regression analysis for the hourly rainfall data and the distribution of observatories of korea meteorological administration. As the results of modeling have shown, duration and rainfall are more correlated than topographic elevation and rainfall, and the model which considers only an elevation exaggerates the amount of rainfall adjustment. Hence the model of duration-elevation-rainfall is more competitive to the natural rainfall event than the model of topographic elevation-rainfall. However this model require to supplement a small number of rainfall observatories and short observed period.

A Study on Construction of Digital Cadastral Map for the GIS (GIS활용을 위한 지적도 전산화 방안 연구 -지적도 도형자료 제작 지침을 중심으로-)

  • 강영옥;안재영;조태영
    • Spatial Information Research
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    • v.6 no.2
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    • pp.201-216
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    • 1998
  • The :Ministry of Transportation and Construction has a plan to finish up the construction of digital topographic map which is based. on airphoto intepretation method by the end of 1998 as a part of NQS (National Geogaphic Information System) Project. The digital topographic map, especially 1:1,000 scale, is used as a basemap of many local government's GIS projects. The digital topographic map, however, does not include property information such as cadastral and urbanplan data that are essential for the GIS database of many local governments. This study aims to develop a set of technical guidelines for the construction of digital cadastral map, which can be used together with the 1:1,000 scale digital topographic map, through 1) analysis of the inconsistency between topographic map and cadastral map, 2) comparison of technical methods for the integration of GIS data that have different accuracy, and 3) requirement analysis of the departments related to urban planning of Seoul Metropolitan Govemment. For this research, edited digital cadastral map has been experimentally produced in pilot study area, a part of Hwanghak-dong, Shindang-dong, and Soongin-dong in Seoul.

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Analysis of Topographical Factors in Woomyun Mountain Debris Flow Using GIS (GIS를 이용한 우면산 토석류 지형인자 분석)

  • Lee, Hanna;Kim, Gihong
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.5
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    • pp.809-815
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    • 2020
  • A number of investigations and studies have been conducted in various fields regarding the sediment disasters of Mt. Woomyeon that occurred in July 2011. We collected and compared the topographic information of the general points where debris flows did not occur and the collapse points where the debris flow occurred in order to find out the characteristics of the collapse points in Woomyeon mountain. The collected topographic information is altitude, curvature, slope, aspect and TPI(topographic position index). As a result of comparison, there were relatively many collapse points at an altitude of 210m to 250m, and at a slope of 30° to 40°. In addition, the risk of collapse was low in a cell where the curvature was close to 0, and the risk was higher in concave terrain than in convex terrain. In the case of TPI, there was no statistical difference between the general points and the collapse points when the analysis radius was larger than 200m, and there was a correlation with the curvature when the analysis radius was smaller than 50m. In the case of debris flows that are affected by artificial structures or facilities, there is a possibility of disturbing the topographic analysis results. Therefore, if a research on debris flow is conducted on a mountain area that is heavily exposed to human activities, such as Woomyeon mountain, diversified factors must be considered to account for this impact.

Topographic Tourism Resources of Mureung Valley in Donghae-si: Analysis and Valuation (동해 무릉계곡의 지형관광자원 분석과 평가)

  • Kwon, Dong Hi
    • Journal of The Geomorphological Association of Korea
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    • v.20 no.3
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    • pp.65-77
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    • 2013
  • This study investigated and analyzed the topographic landscape resources of Mureung Valley in Donghae-si from the viewpoint of geotourism in order to suggest the tourism contents and tour course. A total of 29 topographic landscapes were observed; these are broadly divided into 4 features including weathering landform, mountainous landform, fluvial landform, and structural landform. Major topographies are fluvial landform (13) and weathering landform (12). At least 19 topographies (14 sites, 19 topographic landscapes) are currently used as tourism resources, with 10 topographies having potential to be developed as new tourism resources. The 10 topographic landscapes are as follows: (1) Jamryong Bawi (Hidden Dragon Rock), (2) Janggipan Bawi (Korean Chessboard Rock), (3) Nurungji Bawi (Parched Rice Rock), (4) Damjang Bawi (Fence Rock), (5) Gyedan Bawi (Stairs Rock), (6) Heundeul Bawi (Rocking Rock), (7) Jeopsi Bawi (Dish Rock), (8) Dol Umul (Stone Well), (9) Jogak Bawi (Carved Rock), and (10) Dubu Bawi (Topu Rock). The topographic tour course can be divided into 3 routes considering accessibility and time. Route 1 is a basic one that anyone can easily use; Route 2 and 3 can be used by visitors who have more time to spare or who are more active.