• Title/Summary/Keyword: topographical survey

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A Study on the Development of Topographical Variables and Algorithm for Mountain Classification (산지 경계 추출을 위한 지형학적 변수 선정과 알고리즘 개발)

  • Choi, Jungsun;Jang, Hyo Jin;Shim, Woo Jin;An, Yoosoon;Shin, Hyeshop;Lee, Seung-Jin;Park, Soo Jin
    • 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.

Construction of Sea-Floor Topographic Survey System Based on Echosounder and GNSS (Echosounder와 GNSS 기반 해저지형측량시스템의 구축)

  • Jin-Duk LEE;Yong-Jin CHOI;Jae-Bin LEE
    • Journal of the Korean Association of Geographic Information Studies
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    • v.26 no.1
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    • pp.56-68
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    • 2023
  • A system that extracts seabed topographic information by simultaneously and continuously observing the horizontal position and water depth in the sea by combining a single beam echosounder and GNSS was constructed. By applying the developed system to actual measurements of small-scale sea areas, the effectiveness of bathymetry and sea-floor topographic data acquisition using GNSS and echosounder was examined. By using the developed outdoor program DS-NAV and indoor program DS-CAD and applying the tide level data at the time of actual measurement of the target sea area, it was possible to derive bathymetry results based on the datum level i.e. approximate lowest low water level(A.L.L.W). By using the developed outdoor program DS-NAV and indoor program DS-CAD and applying the tide level data at the time of actual measurement of the target sea area, it was possible to derive the results of bathymetric survey based on the datum level. From database built through the actual measurement. it was possible to create 3D model of the sea-floor topography and extract cross-sections. The results of this study are expected to be economically useful for extracting seabed topographical information from small sea areas or in dredging sites for offshore construction.

The Topographical Factors Affecting the Water Quality of Iwonchon Basin (이원천 유역의 하천수질에 미치는 지형요인)

  • 이호준;방제용
    • The Korean Journal of Ecology
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    • v.22 no.3
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    • pp.101-108
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    • 1999
  • This survey was performed from March 1993 to March 1998, in order to clarify the relationships between water quality and topographical factor. The study sites were two reservoir basins; Kaesim and Jangchan in Iwon-myon, Okchon-gun, Chungcho'ngbukdo Province. Basin shape factors of Kaesim reservoir were at 0.030∼0.210 (mean value 0.090), those of Jangchan reservoir were at 0.217∼0.452 (mean value 0.325). The mean basin shape factor of Jangchan reservoir was 3.61 times larger than that of Kaesim reservoir because its stream width was narrower and mean stream length was shorter. In the correlation between distance from the source of stream (L) and basin area (A), Iwonchon basin was calculated as L=1.44A/sup 0.6/. Circularity ratio was 17.114 in Kaesim (22% of Kum River), and 7.444 in Jangchan. Elongation ratio was 0.357 in Kaesim, 0.636 in Jangchan and 0.282 in Kum River. Precipitation summation period of Jangchan was 1.54 times slower than that of Kaesim. Rainfall reaching time in each small basin was 337.53 min. in A'(Jangchan-ri) basin of Jangchan and 49.26 min in H (Iwon-ri) basin of Kaesim. In the relationship between watershed frequency (Df) and drainage density (Dd), the regression equation was Df=0.023Dd² in Kaesim and Df=0.189Dd² in Jangchan reservoir. As slope degree increased, DO became higher (Y/sub DO/=0.19X+6.5927, r=0.8l), but COD(Y/sub COD/=-0.2092X+9.7104, r=0.52) became lower. Total nitrogen was increased with the increase of basin shape factor and circularity ratio. Ratio of B/sub OD/ to COD was 1/1.2(Y/sub BOD/ = 1.2984 X/sub COD/-3.2004, r=0.9l).

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A Study on the Characteristics of Garden Architecture in Italian Renaissance Villa d'Este (빌라 데스테의 정원건축적 특성에 관한 연구)

  • Kim, Eun-Young;Kim, Kyu-Yeon;Choi, Jong-Hee
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.40 no.4
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    • pp.49-57
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    • 2022
  • This study was conducted with the aim of investigating the garden architectural characteristics of Villa d'Este, which occupies a major role in the exploration of the contrasting background, location, and spatial composition characteristics of Italian Renaissance gardens. The survey for the study was divided into a literature survey and a field survey, and the details are as follows. First, in the mid-to-late 16th century, the villa was built under the direction of Cardinal Ippolito d'Este, and afterwards, the ownership of the villa was restored to the Italian government in 1850 due to financial difficulties. The Villa d'Este, which suffered another damage, is now operated with many visitors after going through the restoration process. Second, in the case of location, it has the characteristics of Urbana located in the city center and has valley-type topographical conditions located at the foot of the mountain.Third, in the case of spatial composition, it is orthogonal to the axis, and each part of the garden is developed, influenced by the contrast principles such as the installation of the Cortile del Belvedere and Villa Madama in the early 16th century. The main building is located in the hills so that you can see the garden and the surrounding scenery at a glance. Fourth, among the components, there were stairs, logia, courtyard, and grotto, fountains, cascades, ponds, and vegetation such as laurels, thorn trees.

Development of Optimal Evacuation Model using Civil Defense Evacuation Facilities Survey Data (민방위 대피시설 실태 분석을 통한 최적의 대피모형 개발에 관한 연구)

  • Yeo, Wookhyun;Park, Namhee;Kim, Taewhan;Koo, Wonyong
    • Journal of the Society of Disaster Information
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    • v.8 no.1
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    • pp.71-80
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    • 2012
  • It is necessary to establish guidelines when we selecting the civil defense evacuation facilities through quantitative analysis by civil defense evacuation facilities volume. The purpose of this study is to evaluate according to population density and distribution of the capacity of evacuation facilities. The results of this study are as follows. First, it is necessary to consider the capacity of evacuation facilities in order to set up the exact districts of civil defense evacuation facilities. Second, basic data based on to compare the condition of civil defense evacuation facilities is produced by an analysis on evacuation status of the target region. Third, it is proved to consider topographical conditions which do not move the shortest distance. Fourth, in order to create a realistic model, it is necessary to consider the model set various parameters.

Deforestation Patterns Analysis of the Baekdudaegan Mountain Range (백두대간지역의 산림훼손경향 분석)

  • Lee, Dong-Kun;Song, Won-Kyong;Jeon, Seong-Woo;Sung, Hyun-Chan;Son, Dong-Yeob
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.4
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    • pp.41-53
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    • 2007
  • The Baekdudaegan Mountain Range is a backbone of the Korean Peninsula which carries special spiritual and sentimental signatures for Koreans as well as significant ecological values for diverse organisms. However, in spite of importance of this region, the forests of Baekdudaegan have been damaged in a variety of human activities by being used as highland vegetable grower, lumber region, grass land, and bare land, and are still undergoing destruction. The existing researches had determined the details of the damage through on-site and recent observations. Such methods cannot provide quantitative and integrated analysis therefore could not be utilized as objective data for the ecological conservation of Baekdudaegan forests. The goal of this study is to quantitatively analyze the forest damage in the Baekdudaegan preservation region through land cover categorization and change detection techniques by using satellite images, which are 1980s, and 1990s Landsat TM, and 2000s Landsat ETM+. The analysis was executed by detecting land cover changed areas from forest to others and analyzing changed areas' spatial patterns. Through the change detection analysis based on land cover classification, we found out that the deforested areas were approximately three times larger after the 1990s than from the 1980s to the 1990s. These areas were related to various topographical and spatial elements, altitude, slope, the distance form road, and water system, etc. This study has the significance as quantitative and integrated analysis about the Baekdudaegan preservation region since 1980s. These results could actually be utilized as basic data for forest conservation policies and the management of the Baekdudaegan preservation region.

Structural Characteristics and Maintenance Mechanism of Ulmus pumila Community at the Dong River, Gangwon-do, South Korea

  • Choung, Heung-Lak;Kim, Chul-Hwan;Yang, Keum-Chul;Chun, Jae-In;Roh, Huan-Chuen
    • The Korean Journal of Ecology
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    • v.26 no.5
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    • pp.255-261
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    • 2003
  • To analyze ecological characteristics of the Ulmus pumila community, an on-the-spot survey was conducted in August, 1998 in the Dong River, Gangwon-do, South Korea. The Ulmus pumila community is partially distributed in Dong River's midstream and upper stream. Topographical characteristics of this community are significant in the point bar or sandbank of the river. The community is classified into two types, disturbed and non-disturbed types, by the effect of flooding. The Ulmus pumila community (bush forests of Siberian elms) is a representative community which forms riparian forests, but its distribution is rare in South Korea. Only in Dong River is the Ulmus pumila distributed enough to form a community, and none is known that is lager than this community in South Korea. The non-disturbance type progresses more homogeneously than the disturbance type because it is formed on riverside banks where it is affected less by flooding. We concluded that the Ulmus pumila community in this study area has characteristics of riparian forests. In South Korea, Ulmus pumila community can be regarded as important element of vegetation landscape constituting riparian forests. Specifically, these riparian forests are evaluated as high in conservation value due to their being formed spontaneously. Moreover, Dong River is regarded as the southern limit of Ulmus pumila, which has a northern origin. The species or community needs continuous interests and conservation countermeasures because there are limitations in its spread of distribution by natural or artificial efforts.

Study about the Standard of Anti-icing System Based on Geography and Geometric Designs (기하구조 및 지형적 요소를 고려한 융설시스템 설치 기준 정립에 관한 연구)

  • Lee, Dong-Hyun;Jeong, Won-Seok;Kim, Ji-Won;Ko, Seok-Beom
    • International Journal of Highway Engineering
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    • v.13 no.2
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    • pp.95-102
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    • 2011
  • Anti-icing system can immediately respond when snowing is expected or the snow comes down on the road surface. It has been recognized that the system can reduce traffic accidents and congestion by quickly removing the frozen road surface area. However, it is very difficult to implement this system due to the expensive equipment installation and operation cost, Recently, there was a developed program for predicting the freezing area using three-dimensional model and tracking the sun path. But, there is no objective analysis method and all developed approaches are different so that the general standard of anti-icing system is needed. In this study, we proposed the decision criteria for determining application priorities of the anti-icing system based on weather and road conditions, i.e., geometric and topographic conditions. Regional climate survey, topographical analysis, and dynamic vehicle simulation considered road geometry and skid resistance was conducted to standardize the installation method of anti-icing system.

Test for the TOPMODEL′s Ability to Predict Water Table Depths of the Transient Saturation Zones which Are Formed on the Steep Hillslope (급사면에 형성된 일시적 포화대의 지하수면깊이에 대한 TOPMODEL의 예측능력 검증)

  • An, Jung-Gi
    • Journal of Korea Water Resources Association
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    • v.36 no.6
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    • pp.1035-1046
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    • 2003
  • In order to evaluate the TOPMODEL's prediction ability for spatial distribution of water table depths, two major assumptions and governing equation of water table depth are tested. For the test, data of hydrological observations are used and a soil survey is made in the steep hillslope with thin soils. Responses of water table and hydraulic properties of soil are coincident with two major assumptions of the TOPMODEL's such as water table gradient parallel to the local topographical slope and exponential decline in transmissivity with depths. Soil texture and the decline rate of transmissivity(f) we homogeneous in space at the 0∼0.3m depths of the soil of the hillslope, but they are heterogeneous in space below its 0.3m depths due to the vertical change of soil texture and the ‘f’. It is shown that the TOPMODEL's equation can be used for simulating distribution of water table depth at the depths with uniform values of the 'f'.

A Display System of Realtime 3D Bathymetry Using Remote Sensing Exploration and Cloud Computing Technologies (원격탐사와 클라우드 컴퓨팅 기술을 활용한 실시간 3D 해저지형의 디스플레이 시스템)

  • Lee, Jong-Hoon;Park, Man-Gon
    • Journal of Korea Multimedia Society
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    • v.17 no.2
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    • pp.152-159
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    • 2014
  • Recently. utilization of remote sensing exploration and cloud computing has been extended to efficient measurement, store, and update of bathymetry map data according to cloud computing technology. In the field of real ocean, water depth measurements and measurement data management, distribution, and display equipment for the development and dissemination have generated a lot of time and cost. To improve these problems, through real-time three-dimensional display system at this location, we can determine the importance of measurement activities, and reduce the time and cost of measurement activities. Data measured from marine probe vessels and remote sensing exploration equipments and other various channels can be handled and managed. In this paper, we propose a realtime three-dimensional display system through the depth measurements from remote sensing exploration. The proposed real-time three-dimensional display system can be effectively applied in the field of measurement of the topographical survey of the land as well as bathymetry of the sea.