• 제목/요약/키워드: Land-cover Types

검색결과 255건 처리시간 0.032초

Assessment of Vegetation Recovery after Forest Fire

  • Yu, Xinfang;Zhuang, Dafang;Hou, Xiyong
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.328-330
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    • 2003
  • The land cover of burned area has changed dramatically since Daxinganling forest fire in Northeastern China during May 6 ? June 4, 1987. This research focused on determining the burn severity and assessment of forest recovery. Burned severity was classified into three levels from June 1987 Landsat TM data acquired just after the fire. A regression model was established between the forest canopy closure from 1999 forest stand map and the NDVI values from June 2000 Landsat ETM+ data. The map of canopy closure was got according to the regression model. And vegetation cover was classified into four types according to forest closure density. The change matrix was built using the classified map of burn severity and vegetation recovery. Then the change conversions of every forest type were analyzed. Results from this research indicate: forest recovery status is well in most of burned scars; and vegetation change detection can be accomplished using postclassification comparison method.

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Change Detection of the Tonle Sap Floodplain, Cambodia, using ALOS PALSAR Data

  • Trung, Nguyen Van;Choi, Jung-Hyun;Won, Joong-Sun
    • 대한원격탐사학회지
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    • 제26권3호
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    • pp.287-295
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    • 2010
  • Water level of the Tonle Sap is largely influenced by the Mekong River. During the wet season, the lacustrine landform and vegetated areas are covered with water. Change detection in this area provides information required for human activities and sustainable development around the Tonle Sap. In order to detect the changes in the Tonle Sap floodplain, fifteen ALOS-PALSAR L-band data acquired from January 2007 to January 2009 and examined in this study. Since L-band is able to penetrate into vegetation cover, it enables us to study the changes according to water level of floodplain developed in the rainforest. Four types of images were constructed and studied include 1) ratio images, 2) correlation coefficient images, 3) texture feature ratio images and 4) multi-color composite images. Change images (in each 46 day interval) extracted from the ratio images, coherence images and texture feature ratio images were formed for detecting land cover change. Two RGB images are also obtained by compositing three images acquired in the early, in the middle and at the end of the rainy season in 2007 and 2008. Combination of the methods results that the change images present the relationship between vegetation and water level, leaf fall forest as well as cultivation and harvest crop.

항공 LiDAR 및 RGB 정사 영상을 이용한 딥러닝 기반의 도시녹지 분류 (Classification of Urban Green Space Using Airborne LiDAR and RGB Ortho Imagery Based on Deep Learning)

  • 손보경;이연수;임정호
    • 한국지리정보학회지
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    • 제24권3호
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    • pp.83-98
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    • 2021
  • 도시녹지는 도시 생태계 건강성 증진을 위한 중요한 요소이며, 건강한 도시 생태계 유지 및 관리를 위해서는 도시녹지의 공간적인 현황 파악이 필요하다. 환경부에서는 2010년 이후부터 총 41개의 분류 항목을 갖는 1m 급 해상도의 세분류 토지피복지도를 제공해오고 있으나, 가로수와 같은 도시 내 고해상도 상세 녹지 정보는 기타 초지로 분류되거나 누락되어 오고 있다. 따라서, 본 연구에서는 수원시 지역을 대상으로 1m 이하 급의 고해상도 원격탐사 자료(항공 LiDAR 및 RGB 정사영상)를 이용하여, 기존 세분류 토지피복지도에서는 나타나지 않는 고해상도의 상세 도시 녹지(수목, 관목 및 초지) 정보를 분류하고자 하였다. 분류 기법으로는 딥러닝 기반의 이미지 분할방법인 U-Net 구조의 모델을 활용하였으며, 분류 항목의 수 및 사용하는 자료의 종류에 따라 총 3가지의 모델(LRGB10, LRGB5, 및 RGB5)을 제안하고 성능을 평가하였다. 검증 지역에 대한 세 모델의 평균 전체 정확도는 각 83.40%(LRGB10), 89.44%(LRGB5), 74.76%(RGB5)이며, 항공 LiDAR와 RGB 정사영상을 함께 사용하여 총 5개의 항목(수목, 관목, 초지, 건물, 및 그 외)을 분류하는 LRGB5 모델의 성능이 가장 높게 나타났다. 수원시의 수목, 관목 및 초지 기준의 전체 녹지 현황은 각 45.61%(LRGB10), 43.47%(LRGB5), 및 44.22%(RGB5)로 나타났으며, 세 모델 모두 기존 세분류 토지피복지도와 비교하여 평균 13.40%의 도시 수목 정보를 더 제공할 수 있는 것으로 나타났다. 더불어 이러한 도시녹지 분류 결과는 향후 중분류 토지피복지도와 같은 기존 GIS 정보와의 융합을 통해 가로수 녹지 비율 현황 등 추가적인 상세 녹지 현황 정보를 제공할 수 있어, 다양한 도시녹지 연구 및 정책의 기초 자료로 활용될 수 있을 것으로 기대된다.

Comparison of Fusion Methods for Generating 250m MODIS Image

  • Kim, Sun-Hwa;Kang, Sung-Jin;Lee, Kyu-Sung
    • 대한원격탐사학회지
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    • 제26권3호
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    • pp.305-316
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    • 2010
  • The MODerate Resolution Imaging Spectroradiometer (MODIS) sensor has 36 bands at 250m, 500m, 1km spatial resolution. However, 500m or 1km MODIS data exhibits a few limitations when low resolution data is applied at small areas that possess complex land cover types. In this study, we produce seven 250m spectral bands by fusing two MODIS 250m bands into five 500m bands. In order to recommend the best fusion method by which one acquires MODIS data, we compare seven fusion methods including the Brovey transform, principle components algorithm (PCA) fusion method, the Gram-Schmidt fusion method, the least mean and variance matching method, the least square fusion method, the discrete wavelet fusion method, and the wavelet-PCA fusion method. Results of the above fusion methods are compared using various evaluation indicators such as correlation, relative difference of mean, relative variation, deviation index, peak signal-to-noise ratio index and universal image quality index, as well as visual interpretation method. Among various fusion methods, the local mean and variance matching method provides the best fusion result for the visual interpretation and the evaluation indicators. The fusion algorithm of 250m MODIS data may be used to effectively improve the accuracy of various MODIS land products.

Simulation and validation of flash flood in the head-water catchments of the Geum river basin

  • Duong, Ngoc Tien;Kim, Jeong Bae;Bae, Deg-Hyo
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2021년도 학술발표회
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    • pp.138-138
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    • 2021
  • Flash floods are one of the types of natural hazards which has severe consequences. Flash floods cause high mortality, about 5,000 deaths a year worldwide. Flash floods usually occur in mountainous areas in conditions where the soil is highly saturated and also when heavy rainfall happens in a short period of time. The magnitude of a flash flood depends on several natural and human factors, including: rainfall duration and intensity, antecedent soil moisture conditions, land cover, soil type, watershed characteristics, land use. Among these rainfall intensity and antecedent soil moisture, play the most important roles, respectively. Flash Flood Guidance is the amount of rainfall of a given duration over a small stream basin needed to create minor flooding (bank-full) conditions at the outlet of the stream basin. In this study, the Sejong University Rainfall-Runoff model (SURR model) was used to calculate soil moisture along with FFG in order to identify flash flood events for the Geum basin. The division of Geum river basin led to 177 head-water catchments, with an average of 38 km2. the soil moisture of head-water catchments is considered the same as sub-basin. The study has measured the threshold of flash flood generation by GIUH method. Finally, the flash flood events were used for verification of FFG. The results of the validation of seven past independent events of flash flood events are very satisfying.

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GLCM기법을 이용한 전정색 위성영상에서의 도시경계 추출 (Extraction of Urban Boundary Using Grey Level Co-Occurrence Matrix Method in Pancromatic Satellite Imagery)

  • 김기홍;최승필;육운수;손홍규
    • 대한토목학회논문집
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    • 제26권1D호
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    • pp.211-217
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    • 2006
  • 도시화는 토지 이용과 토지 피복에 많은 변화를 가져오며 토지 이용의 변화는 도시확장과 밀접한 관계를 가지게 된다. 위성영상을 이용하여 도시화에 관한 주제도를 제작하는 것은 토지 이용의 변화에 관한 분석과 자료 제작에 있어서 중요한 방법 중의 하나이다. 과거의 위성영상은 도시정보를 얻을 수 있는 유용한 정보이며 CORONA는 1960년부터 1972년 사이에 운용된 미국의 고해상도 첩보위성영상으로 1995년 일반에 공개가 되었다. 그러나 코로나 위성영상은 파노라마 방식으로 촬영되었기 때문에 여러 가지 형태의 왜곡이 영상에 존재한다. 본 논문에서는 영상의 왜곡을 보정하여 공선조건식을 이용하는 수학적인 모델을 제안하였다. 기하보정 후 서울시 모자이크 영상을 제작하였으며 1972년 CORONA 영상과 1995년 SPOT 영상에 GLCM 기법과 육안판독을 이용하여 도시경계를 추출함으로서 서울시의 변화모습을 정량적으로 관찰할 수 있었다.

Vegetation of the Khogno Khan Natural Reserve, Mongolia

  • Gombosuren, Tsolmon;Kim, Jong-Won
    • The Korean Journal of Ecology
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    • 제24권6호
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    • pp.365-370
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    • 2001
  • The vegetation of the Khogno Khan Natural Reserve of the central Mongolia was studied in terms of the Zurich-Montpellier School's method. Twenty plant communities were identified from the three different landscape types such as mountain areas(63%), plains(32%), and wetlands(5%). Actual vegetation map using five vegetation domains was accomplished in order to understand the spatial distribution of regional vegetation. Steppe vegetation of 88% vegetation cover to the whole area is representative, which is composed of a matrix of landscape. The birch-aspen forests and the elm bush forests are relics as a patch distribution. It is recognized that the whole territory of protected area be under the effects of severe grazing from the phytosociological viewpoint.

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Space Technology in Environmental Health (Emerging Vial Disease)

  • Nakhapakorn, Kanchana;Andrianasolo, Haja
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.411-416
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    • 2002
  • The emergence of viral diseases transmitted is nowadays a central problem in the world. Problem, which is becoming very critical in developing countries, where the health systems are not yet enough developed to face the bursting of such diseases. Emerging viral diseases constitute one of the major threats to human being that are arising in the modern world. Besides bio-chemical and medical researches, new orientations are developed to understand the environmental dimensions of such emergence. Questions concerning the inter-plays between the environmental and disease dynamics are building up new investigations, both in remote sensing and GIS, for the elaboration of levels of organization of space and environment in relation to incidences, to gain understandings in these issues. Environmental attributes attached to land cover types: area, spatial heterogeneity and physical state, are derived from remote sensing and applied to uncover related dimensions of the Dengue disease.

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계층 구조와 텍스쳐 특징을 이용한 위성 영상의 분류 (Classification of satellite image using pyramid structure and texture features)

  • 엄기문;김정호;김정기;이쾌희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1992년도 하계학술대회 논문집 A
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    • pp.449-452
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    • 1992
  • Before performing an adaptive stereo matching using satellite images, classification is needed as a preprocessing step. This paper describes that classification of three land cover types : river, mountain, and agricultural fields. We proposed that classification algorithm using pyramid structure and texture features. Results of applying the proposed algorithm to satellite image improved classification accuracy.

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MAPPING SOIL ORGANIC MATTER CONTENT IN FLOODPLAINS USING A DIGITAL SOIL DATABASE AND GIS TECHNIQUES: A CASE STUDY WITH A TOPOGRAPHIC FACTOR IN NORTHEAST KANSAS

  • Park, Sunyurp
    • Spatial Information Research
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    • 제10권4호
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    • pp.533-550
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    • 2002
  • Soil organic matter (SOM) content and other physical soil properties were extracted from a digital soil database, the Soil Survey Geographic (SSURGO) database, to map the amount of SOM and determine its relationship with topographic positions in floodplain areas along a river basin in Douglas County, Kansas. In the floodplains, results showed that slope and SOM content had a significant negative relationship. Soils near river channels were deep and nearly level, and they had the greatest SOM content in the floodplain areas. For the whole county, SOM content was influenced primarily by soil depth and percent SOM by weight. Among different slope areas, soils on mid-range slopes (10-15%) and ridgetops had the highest SOM content because they had relatively high percent SOM content by weight and very deep soils, respectively. SOM content was also significantly variable among different land cover types. Forest/woodland had significantly higher SOM content than others, followed by cropland, grassland, and urban areas.

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