• Title/Summary/Keyword: aerial photographs

Search Result 298, Processing Time 0.023 seconds

CROSS-VALIDATION OF ARTIFICIAL NEURAL NETWORK FOR LANDSLIDE SUSCEPTIBILITY ANALYSIS: A CASE STUDY OF KOREA

  • LEE SARO;LEE MOUNG-JIN;WON JOONG-SUN
    • Proceedings of the KSRS Conference
    • /
    • 2004.10a
    • /
    • pp.298-301
    • /
    • 2004
  • The aim of this study is to cross-validate of spatial probability model, artificial neural network at Boun, Korea, using a Geographic Information System (GIS). Landslide locations were identified in the Boun, Janghung and Youngin areas from interpretation of aerial photographs, field surveys, and maps of the topography, soil type, forest cover and land use were constructed to spatial data-sets. The factors that influence landslide occurrence, such as slope, aspect and curvature of topography, were calculated from the topographic database. Topographic type, texture, material, drainage and effective soil thickness were extracted from the soil database, and type, diameter, age and density of forest were extracted from the forest database. Lithology was extracted from the geological database, and land use was classified from the Landsat TM image satellite image. Landslide susceptibility was analyzed using the landslide­occurrence factors by artificial neural network model. For the validation and cross-validation, the result of the analysis was applied to each study areas. The validation and cross-validate results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations.

  • PDF

Analysis of Temporal River Change Using Aerial Photographs and a GIS (항공사진과 GIS기반의 하천 시계열 분석)

  • Park, Eun-Ji;Kim, Kye-Hyun
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
    • /
    • 2008.10a
    • /
    • pp.7-12
    • /
    • 2008
  • 근래에 들어 급속한 산업화에 따라 하천 고유의 특성을 간과한 채 개발 위주의 하천 정비사업이 시행되고 있으며 이는 하천의 인공화 및 생태계의 교란 등 많은 문제점을 낳고 있다. 이에 따라 하천 및 하도 환경에 미치는 영향이 심각할 뿐만 아니라 홍수 피해 또한 급격히 증가하고 있다. 지금까지의 치수 위주의 하천 정비를 벗어나 친환경적인 하천으로의 복원 사업이 필요한 실정이며, 이는 새로운 하천 관리 기술의 도입이 필요함을 의미한다. 따라서 본 연구에서는 항공사진과 GIS기반의 하천 시계열 분석을 수행하여 새로운 하천 관리 기술 도입에 응용할 수 있는 방안을 제시하고자 하였다. 분석을 위하여 댐 하류의 하천교란 및 적응현장 시범지역을 선정한 후 대상 지역의 항공사진을 GIS화하여 하천 교란 실태를 분석하는 데에 필요한 저수로와 제방 및 기타 자료를 shape 파일 형태로 생성하였다. 생성된 자료를 바탕으로 하천의 사행도 및 유로 변동 현황 분석을 실시함에 따라 하천의 변화 양상을 확인하였으며 대상 하천의 사행도 및 저수의 구체적인 제반 수치를 제시할 수 있었다. 또한 분석 결과를 바탕으로 현재 이루어지고 있는 하천의 정비 및 복원 사업이 하천의 흐름에 어떠한 영향을 미치는 지 예측을 가능하게 하였다. 본 연구에서 규명된 경년별 하천 형태의 변화 추세와 하천 부지의 물리적 특성 변화 양상을 기본 자료로 한다면 하천 관리에 있어 수리 수문학적 분석이 용이하리라 사료된다. 향후 연구에서는 GIS기반의 하천 관리 방안 수립에 대한 심층 연구가 뒤따라야 할 것이다.

  • PDF

Spatial Distribution and Casual Causes of Shallow Landslides in Jinbu Area of Korea

  • Park, Jin Woo;Choi, Byoung Koo;Kim, Myung Hwan;Cha, Du Song
    • Journal of Forest and Environmental Science
    • /
    • v.33 no.2
    • /
    • pp.130-135
    • /
    • 2017
  • In temperate monsoon regions, extensive shallow landslides triggered by heavy rainfall are recurrent phenomena in mountainous areas. 1,357 landslides over Jinbu area, Korea that totaled 127 km2 were identified from aerial photographs and field survey. We examined characteristics of rainfall-induced shallow landslides and casual factors affecting landslide distribution with respect to topographic and forest settings, and land use. Most landslides occurred in the study area were the results of a complex combination of precondition, preparatory factors and triggering factors. Cumulative rainfall and high intensity rainfall during short period of time made the study area very sensitive to landslides and played as catalysts to enable other factors including topographic and forest settings, and land use to act more effectively. In addition, some landslides at lower elevation involved channel incision or bank erosion influenced by land use changes such as deforestation and intensification of agriculture surrounding riparian forests or hillslopes. The results suggest that most of landslide were triggered by heavy rainstorms while topographic, forest settings, and land use affected landslide distribution occurred in the study area.

The Analysis of 3D Position Accuracy of Multi-Looking Camera (다각촬영카메라의 3차원 위치정확도 분석)

  • Go, Jong-Sik;Choi, Yoon-Soo;Jang, Se-Jin;Lee, Ki-Wook
    • Spatial Information Research
    • /
    • v.19 no.3
    • /
    • pp.33-42
    • /
    • 2011
  • Since the method of generating 3D Spatial Information using aerial photographs was introduced, lots of researches on effective generation methods and applications have been performed. Nadir and oblique imagery are acquired in a same time by Pictometry system, and then 3D positioning is processed as Multi-Looking Camera procedure. In this procedure, the number of GCPs is the main factor which can affect the accuracy of true-orthoimage. In this study, 3D positioning accuracies of true-orthoimages which had been generated using various number of GCPs were estimated. Also, the standard of GCP number and distribution were proposed.

Characteristics of woodland changes in an agricultural landscape - The case of Gwangju (농촌경관지역의 산림변화 특성)

  • Lee, Young-Chang;Jung, Woon-Joo;Kim, Keun-Ho
    • Korean Journal of Agricultural Science
    • /
    • v.38 no.3
    • /
    • pp.429-436
    • /
    • 2011
  • Recent landscape changes from human activities, such as agricultural development and urbanisation frequently result in the loss of habitats, the reduction in habitat patch size and an increasing isolation of habitat patches. However, there is little information on woodland changes in agricultural landscapes. Therefore, the aim of this research was to assess spatial characteristics and changes of woodland in an agricultural landscape and how these may have had an impact on ecological process for 33 years. One of the agricultural landscape character units was analysed based on aerial photographs from 1976, 1983, 1994, 2002 and 2009 in Gwangju city. The results indicated that landscape ecological metrics clearly showed that they could be used to monitor changes of woodland ecological conditions during the past 33 years. The results imply that particularly human activities have been leading to the decrease of the mean size of woodland patches and finally result in woodland isolation. These changes may have a negative impact on woodland bird species in the study area. This woodland information can be used to identify the potential and specific needs for setting priorities for conservation planning.

Determination of the latest fault movement by trench survey at Galgok-Chisil site in the northern Ulsan fault system (울산단층북부 갈곡리 치실 지점의 마지막 단층 운동시기 결정)

  • Choi, Weon-Hack;Chang, Chun-Joong;Inoue, D.;Tanaka, T.
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 2005.03a
    • /
    • pp.11-17
    • /
    • 2005
  • Along the Ulsan Fault System, many Quaternary faults have been reported and investigated with outcrop observation and trench excavation to clarify the neotectonic movements and fault parameters such as length, displacement, slip rate and recurrence interval. In the northern part of the Ulsan fault system, we have interpreted small scale(1:10,000) aerial photographs and extracted lineaments by geomophological features to select trench site. After precise field survey and tracing for lineaments, two trench sites at Galgokri, Gyeongju were selected on the lineament to elucidate the fault movement history. One is successful in finding faults but the other is not. In the Galgok-Chisil trench(3m(w) x 1.5m(d) x 10m(l)), very closed two Quaternary faults cut the alluvial deposits of which age shows about 10-3ka. More than three times of fault movements can be inferred by geologic structures and C-14 dating. Repeatedly fault movements had been occurred before 10 ka, between 10ka-4.9 ka, between 4.9-1.4 ka at Galgok-Chisil trench section.

  • PDF

Implementation of Digital Image Processing for Coastline Extraction from Synthetic Aperture Radar Imagery

  • Lee, Dong-Cheon;Seo, Su-Young;Lee, Im-Pyeong;Kwon, Jay-Hyoun;Tuell, Grady H.
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.25 no.6_1
    • /
    • pp.517-528
    • /
    • 2007
  • Extraction of the coastal boundary is important because the boundary serves as a reference in the demarcation of maritime zones such as territorial sea, contiguous zone, and exclusive economic zone. Accurate nautical charts also depend on well established, accurate, consistent, and current coastline delineation. However, to identify the precise location of the coastal boundary is a difficult task due to tidal and wave motions. This paper presents an efficient way to extract coastlines by applying digital image processing techniques to Synthetic Aperture Radar (SAR) imagery. Over the past few years, satellite-based SAR and high resolution airborne SAR images have become available, and SAR has been evaluated as a new mapping technology. Using remotely sensed data gives benefits in several aspects, especially SAR is largely unaffected by weather constraints, is operational at night time over a large area, and provides high contrast between water and land areas. Various image processing techniques including region growing, texture-based image segmentation, local entropy method, and refinement with image pyramid were implemented to extract the coastline in this study. Finally, the results were compared with existing coastline data derived from aerial photographs.

The Land Surface Temperature Analysis of Seoul city using Satellite Image (위성영상을 통한 서울시 지표온도 분석)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
    • /
    • v.22 no.1
    • /
    • pp.19-26
    • /
    • 2013
  • The propose of this study is to analyze the optimum spatial resolution of the urban spatial thermal environment structure and to evaluate of the possibility detection using aerial photographs and thermal satellite images. The proper techniques of the optimum spatial resolution for the urban spatial thermal environment structure were analyzed. Thermal infrared satellite image of Seoul city were used for the change rate of surface temperature variation and suggested to the spatial extent and effects of urban surface characteristics and spatial data was interpreted as regions. To extract the surface temperature, Landsat thermal infrared satellite image compared with an automatic weather station data and in the field of the measured temperature and surface temperature by thermal environment affects, the spatial domain has been verified. The surface temperature of the satellite images to extract after adjusting surface temperature isotherms were constructed. The changes in surface temperature from 2008 to 2012 the average surface temperature observation images of changing areas were divided into space. The results of this study are as follows: Through analysis of satellite imagery, Seoul city surface temperature change due to extraction comfort indices were classified into four grades. The comfort index indicative of the temperature of Gangnam-gu, $23.7{\sim}27.2(^{\circ}C)$ range and Songpagu, a $22.7{\sim}30.6(^{\circ}C)$ respectively, the surface temperature of Yeouido $25.8{\sim}32.6(^{\circ}C)$ were in the range.

Automatic Building Reconstruction with Satellite Images and Digital Maps

  • Lee, Dong-Cheon;Yom, Jae-Hong;Shin, Sung-Woong;Oh, Jae-Hong;Park, Ki-Surk
    • ETRI Journal
    • /
    • v.33 no.4
    • /
    • pp.537-546
    • /
    • 2011
  • This paper introduces an automated method for building height recovery through the integration of high-resolution satellite images and digital vector maps. A cross-correlation matching method along the vertical line locus on the Ikonos images was deployed to recover building heights. The rational function models composed of rational polynomial coefficients were utilized to create a stereopair of the epipolar resampled Ikonos images. Building footprints from the digital maps were used for locating the vertical guideline along the building edges. The digital terrain model (DTM) was generated from the contour layer in the digital maps. The terrain height derived from the DTM at each foot of the buildings was used as the starting location for image matching. At a preset incremental value of height along the vertical guidelines derived from vertical line loci, an evaluation process that is based on the cross-correlation matching of the images was carried out to test if the top of the building has reached where maximum correlation occurs. The accuracy of the reconstructed buildings was evaluated by the comparison with manually digitized 3D building data derived from aerial photographs.

Evaluation of a Land Use Change Matrix in the IPCC's Land Use, Land Use Change, and Forestry Area Sector Using National Spatial Information

  • Park, Jeongmook;Yim, Jongsu;Lee, Jungsoo
    • Journal of Forest and Environmental Science
    • /
    • v.33 no.4
    • /
    • pp.295-304
    • /
    • 2017
  • This study compared and analyzed the construction of a land use change matrix for the Intergovernmental Panel on Climate Change's (IPCC) land use, land use change, and forestry area (LULUCF). We used National Forest Inventory (NFI) permanent sample plots (with a sample intensity of 4 km) and permanent sample plots with 500 m sampling intensity. The land use change matrix was formed using the point sampling method, Level-2 Land Cover Maps, and forest aerial photographs (3rd and 4th series). The land use change matrix using the land cover map indicated that the annual change in area was the highest for forests and cropland; the cropland area decreased over time. We evaluated the uncertainty of the land use change matrix. Our results indicated that the forest land use, which had the most sampling, had the lowest uncertainty, while the grassland and wetlands had the highest uncertainty and the least sampling. The uncertainty was higher for the 4 km sampling intensity than for the 500 m sampling intensity, which indicates the importance of selecting the appropriate sample size when constructing a national land use change matrix.