• 한국농공학회논문집
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• 제56권3호
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• pp.55-64
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• 2014

While utilizing high resolution satellite image for land use classification has been popularized, object-oriented classification has been adapted as an affordable classification method rather than conventional statistical classification. The aim of this study is to extract the paddy field area using object-oriented classification with time series NDVI from high-resolution satellite images, and the RapidEye satellite images of Jaeryung-gun in North Korea were used. For the implementation of object-oriented classification, creating objects by setting of scale and color factors was conducted, then 3 different land use categories including paddy field, forest and water bodies were extracted from the objects applying the variation of time-series NDVI. The unclassified objects which were not involved into the previous extraction classified into 6 categories using unsupervised classification by clustering analysis. Finally, the unsuitable paddy field area were assorted from the topographic factors such as elevation and slope. As the results, about 33.6 % of the total area (32313.1 ha) were classified to the paddy field (10847.9 ha) and 851.0 ha was classified to the unsuitable paddy field based on the topographic factors. The user accuracy of paddy field classification was calculated to 83.3 %, and among those, about 60.0 % of total paddy fields were classified from the time-series NDVI before the unsupervised classification. Other land covers were classified as to upland(5255.2 ha), forest (10961.0 ha), residential area and bare land (3309.6 ha), and lake and river (1784.4 ha) from this object-oriented classification.

• Journal of Forest and Environmental Science
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• 제31권3호
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• pp.177-191
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• 2015

The effect of environmental variables on the presence and abundance of tree species in a tropical lowland undisturbed limestone and non-limestone forest in Ben En National Park, Vietnam was investigated. The relationships between 13 environmental variables and 29 tree species with a DBH ${\geq}10cm$, as well as between six 6 physical variables with 26 species of seedling and sapling communities were assessed by canonical correspondence analysis (CCA). Data concerning all tree species ${\geq}10cm$ DBH were collected from eighteen $400m^2$ sample plots, while the abundance of regeneration (all individuals ${\leq}5cm$ DBH) was counted in fifty $2{\times}20m$ strip-plots. The significance of species-environments correlations were tested by distribution-free Monte Carlo tests. The CCA of the 29 examined tree species and 13 environmental variables indicated that the presence and abundance of the tree species were closely related to topographic factors. We may confirm that soil properties including pH, soil moisture content, and soil textures, were the most crucial factor in tree species composition and their distribution. Several species including Pometia pinnata, Amesiodendron chinense, Gironniera cuspidate, Cinnamomum mairei, and Caryodaphnopsis tonkinensis were not controlled by soil properties and topographic variables. The CCA also indicated that the abundance of regeneration tree species at all sites had positive and significant correlations with soil depth, while the occurrence of several other tree species (such as Koilodepas longifolium and Aglaia dasyclada) was positively correlated with a higher slope and rocky outcrop.

• Spatial Information Research
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• 제20권3호
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• pp.57-66
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• 2012

강원도의 경우 대부분 산지로 이루어져 있어 산사태로 인한 피해가 매우 크다. 이러한 산사태를 예방하기 위해서는 산사태 발생에 영향을 미치는 기초적인 관련 인자를 분석하는 것이 중요하다. 본 연구에서는 강원도 인제군 인제읍 덕산리 지역을 대상으로 재해 직후 촬영된 항공사진을 이용하여 육안판독에 의한 디지타이징 방법으로 산사태 발생 및 미발생 지점을 추출하였으며, GIS를 이용한 지형도, 임상도, 토양도의 중첩분석을 통하여 산사태 관련 인자에 대하여 지형학적, 임상학적, 토양학적 특성을 수량화 2종법을 이용하여 분석하였다. 분석결과 경사도는 $20^{\circ}{\sim}35^{\circ}$ 사이에서 산사태가 많이 발생하였으며, 임상 인자의 경우 침엽수가 산사태 발생 빈도와 더 큰 연관성을 보였다. 토양 인자의 경우 유효 토심이 얕을수록, 토양모재가 산성암일수록 산사태 발생빈도가 높게 나타났다.

• 한국수자원학회논문집
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• 제40권4호
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• pp.287-297
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• 2007

DEM을 이용하여 국부경사와 기여면적 사이의 규모에 따른 거동특성을 조사하여 면적한계기준과 경사-면적한계 기준이 상호보완적인 형태의 수로망 추적절차를 제시하였다. 상기방법과 현장자료에 대한 적용을 통하여 유역의 경사는 공간적으로 대규모의 산포경향을 갖는 지형인자임을 확인할 수 있었다. 양자의 규모에 따른 거동특성권역에 따라 지면의 형상은 발산지형과 수렴지형으로 분류될 수 있었다. 본 연구에서 제시한 수로망 동정 절차를 설마천 시험 유역에 대하여 수행한 결과 유역의 동적 거동을 확인할 수 있었다. 또한 이로부터 지형도를 이용한 수작업에 기초한 방법에 비하여 하천두부의 거동과 수로망의 동적특성을 잘 표현하고 있음을 볼 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.82-84
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• 2003

Watershed boundaries and flow paths within the watershed are the most important factors required in watershed analysis. Most often the derivation of watershed boundaries and stream network and flow paths is based on topographical maps but spatial variation of flow direction is not clearly understandable using this method. Water resources projects currently use 1: 50, 000-scale ground survey or aerial photography-based topographical maps to derive watershed boundary and stream network. In basins, where these maps are not available or not accessible it creates a real barrier to watershed geo-spatial analysis. Such situations require the use of global datasets, like GTOPO30. Global data sets like ETOPO5, GTOPO30 are the only data sets, which can be used to derive basin boundaries and stream network and other terrain variations like slope aspects and flow direction and flow accumulation of the watershed in the absence of topographic maps. Approximately 1-km grid-based GTOPO 30 data sets can derive better outputs for larger basins, but they fail in flat areas like the Karkheh basin in Iran and the Amudarya in Uzbekistan. A new window in geo-spatial hydrology has opened after the launching of the space-borne satellite stereo pair of the Terra ASTER sensor. ASTER data sets are available at very low cost for most areas of the world and global coverage is expected within the next four years. The DEM generated from ASTER data has a reasonably good accuracy, which can be used effectively for hydrology application, even in small basins. This paper demonstrates the use of stereo pairs in the generation of ASTER DEMs, the application of ASTER DEM for watershed boundary delineation, sub-watershed delineation and explores the possibility of understanding the drainage flow paths in irrigation command areas. All the ASTER derived products were compared with GTOPO and 1:50,000-based topographic map products and this comparison showed that ASTER stereo pairs can derive very good data sets for all the basins with good spatial variation, which are equal in quality to 1:50,000 scale maps-based products.

• 한국수자원학회논문집
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• 제55권spc1호
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• pp.1223-1234
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• 2022

기후변화에 대처하기 위한 온실가스 저감 노력은 상하수도 분야에서도 활발하게 진행되어 왔으며, 특히, 상수도 생산 및 공급과정에서 많은 에너지를 소비하는 상수관망의 에너지를 절감하기 위한 많은 기술개발이 이루어져왔다. 상수관망의 에너지 절감은 지형의 기복으로 발생되는 구조적 손실의 저감과 누수 및 마찰손실로 인한 운영 상 손실의 효율화를 통해 성취될 수 있음에도 실제 상수관망의 에너지 수지를 분석하는 단계에서 이들 인자들 상호간의 복합적 작용으로 인해 해석적인 접근뿐 아니라 수치모형을 이용한 모의에서도 한계를 노출하여 왔다. 본 연구에서는 지형의 기복, 누수 및 마찰손실의 유무에 따라 변화하는 유량, 압력수두 및 에너지를 5가지의 상수관망 상태(가설적 상태, 이상적 상태, 누수가 포함된 이상적 상태, 누수가 배제된 실제 상태, 실제 상태)에 대하여 수리 물리적 방정식을 도출하고, 이를 단순한 형태의 상수관망에 적용함으로서 에너지의 정량적 분석 및 분류, 각종 에너지 수지 구성요소별 분석과 이를 이용한 상수도 시스템의 에너지 진단이 가능하도록 하였다.

• 한국지형학회지
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• 제27권2호
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• pp.1-17
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• 2020

This study evaluated a debris landform distribution potential area map in the southwest region of the Korean peninsula. A GIS spatial integration technique and logistic regression method were used to produce a distribution potential area map. Seven topographic and environmental factors were considered for analysis and 28 different data set were combined and used to get most effective results. Moreover, in an accuracy assessment, the extracted results of the Distribution Potential area were evaluated by conducting a cross-validation module. Block stream showed the highest accuracy in the combination No. 6, and that DEM (digital elevation model) and TWI (topographic wetness index) have relatively high influences on the production of the Block stream Distribution Potential area map. Talus showed the highest accuracy in the combination No. 13. We also found that slope, TWI and geology have relatively high influences on the production of the Talus Distribution Potential area map. In addition, fieldwork confirmed the accuracy of the input data that were used in this study, and the slope and geology were also similar. It was also determined that these input data were relatively accurate. In the case of angularity, the block stream was composed of sub-rounded and sub-angular systems and Talus showed differences according to the terrain formation. Although the results of the rebound strain measurement using a Schmidt's hammer did not shown any difference in topographic conditions, it is determined that the rebound strain results reflected the underlying geological setting.

• Geosciences Journal
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• 제22권6호
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• pp.1053-1067
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• 2018

This paper uses a probability-based approach to study the spatial relationships between landslides and their causative factors in the Mingchukur area, Bostanlik districts of Tashkent, Uzbekistan. The approach is based on digital databases and incorporates methods including probability analysis, spatial pattern analysis, and interactive mapping. First, an object-oriented conceptual model for describing landslide events is proposed, and a combined database of landslides and environmental factors is constructed by integrating various databases within a unifying conceptual framework. The frequency ratio probability model and landslide occurrence data are linked for interactive, spatial evaluation of the relationships between landslides and their causative factors. In total, 15 factors were analyzed, divided into topography, hydrology, and geology categories. All analyzed factors were also divided into numerical and categorical types. Numerical factors are continuous and were evaluated according to their $R^2$ values. A landslide susceptibility map was constructed based on conditioning factors and landslide occurrence data using the frequency ratio model. Finally, the map was validated and the accuracy showed the satisfactory value of 83.3%.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.430-433
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• 2005

In this study, weight of evidence(WOE) technique based on the bayesian method was applied to estimate the groundwater yield characteristics in the Pocheon area in Kyungki-do. The ground water preservation depends on many hydrogeologic factors that include hydrologic data, landuse data, topographic data, geological map and other natural materials, even with man-made things. All these data can be digitally collected and managed by GIS database. In the applied technique of WOE, The prior probabilities were estimated as the factors that affect the yield on lineament, geology, drainage pattern or river system density, landuse and soil. We calculated the value of the Weight W+, W- of each factor and estimated the contrast value of it. Results by the ground water yield characteristic calculations were presented in the form of posterior probability map to the consideration of in-situ samples. It is concluded that this technique is regarded as one of the effective technique for the feasibility mapping related to detection of groundwater bearing zones and its spatial pattern.

• 대한공간정보학회지
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• 제11권1호
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• pp.39-44
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• 2003

최근에, GIS는 수자원 분야에서 그 적용성이 증가 되고 있다. 수문모형에서 GIS 모델링은 일반적으로 하도망, 그리고 유역의 구분, 분기점의 추출을 위해서 사용된다. 추출된 하도망 위에 지형도와 토지이용도를 overlay 시킴으로써, 수문모형에 요구되는 입력파일을 만든다. 이는 GIS가 수문해석을 하는데 있어서 설계자의 주관적인 요소를 객관적으로 발전시킬 수 있는 방안이라 해석되기 때문이다. 따라서 본 연구에서는 HEC-GEOHMS에서 추출된 수문지형인자와 기존의 방법을 비교하였다. 전반적으로 유사한 결과를 나타내었으나 평지지역에 대한 프로그램상의 오류가 나타났다. 향후 오류를 보완한다면 입력매개변수로서 중요 요소인 지형정보를 기존의 방법을 탈피하여 GIS기법을 이용하여 기존방법과 다른 신뢰성 있는 정보를 획득하여 실무에 적용에 있어 기본적인 자료로 활용할 수 있을것이다.