• Title/Summary/Keyword: SATELLITE IMAGE

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A Technique for Mixed Pixel Extraction by Canonical Vector Analysis (정준벡터분석에 의한 혼합화소 해석기법에 관한 연구)

  • 박민호
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.1
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    • pp.75-84
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    • 1998
  • To achieve more accurate information from satellite image data, a research on a technique for mixed pixel ex-traction has been produced. The mixed pixels with only two land covers have been experimented. By analyzing canonical vector in canonical correlation classification, the mixed pixels have been classified. The ratio of the two canonical weighted values-the elements of canonical vector have been used as a threshold to discriminate mixed pixels. In case of the classification for the mixed pixels of bridge and water class in TM data before or after the 1st of September, the threshold for the optimal classification of the mixed pixels is 4.0. That is, if the ratio of the two canonical weighted values is less than 4.0, the pixel is a mixed pixel. Also, using the distribution of canonical weighted values, the constitution percentages of land covers within one mixed pixel can be approximately deducted. The accuracy of mixed pixel extraction for experimental area is 90% and quite acceptable. Conclusively, a technique for mixed pixel extraction by canonical vector analysis is effective.

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Characteristics of Ocean Scanning Multi-spectral Imager (OSMI)

  • Cho, Young-Min;Yong, Sang-Soon;Woo, Sun-Hee;Lee, Sang-Gyu;Oh, Kyoung-Hwan;Paik, Hong-Yul
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.319-324
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    • 1998
  • Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-purpose SATellite (KOMPSAT) to perform worldwide ocean color monitoring for the study of biological oceanography. The instrument images the ocean surface using a whisk-broom motion with a swath width of 800 km and a ground sample distance (GSD) of < 1 km over the entire field-of-view (FOV). The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The instrument also performs sun calibration and dark calibration for on-board instrument calibration. The OSMI instrument is a multi-spectral imager covering the spectral range from 400 nm to 900 nm using a CCD Focal Plane Array (FPA). The ocean colors are monitored using 6 spectral channels that can be selected via ground commands after launch. The instrument performances are fully measured for 8 basic spectral bands centered at 412nm, 443nm, 490nm, 510nm, 555nm, 670nm, 765nm and 865nm during ground characterization of instrument. In addition to the ground calibration, the on-board calibration will also be used for the on-orbit band selection. The on-orbit band selection capability can provide great flexibility in ocean color monitoring.

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Sea Surface Cold Water near the Southeastern Coast of Korea: Wind Effect (한국(韓國) 남동해안(南東海岸)부근의 해표면(海表面) 냉수(冷水) : 바람의 영향(影響))

  • Byun, Sang-Kyung
    • 한국해양학회지
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    • v.24 no.3
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    • pp.121-131
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    • 1989
  • Cold water observed at sea surface near the southeastern coast of Korea in summers 1982 and 1983 was studied by using data of hydrography, sea level, wind and satellite image. In summer season when water column shows 3-layered structure a "full" upwelling occurs by southwesterly transient wind continuing for several days. During upwelling event, surface water of high temperature moved offshore, middle water of low temperature outcropped to the sea surface, and sea level was lowered, however, equilibrium depth of surface layer was not changed. It may be concluded that cold water at the surface originates from middle layer and strong surface front is a result of surfacing of seasonal thermocline. In order to see the relationship between position of surface front and wind input, a model of Csanady (1982) was applied in a rigid lid approximation. The results show that frontal position can be determined by wind input and water structure near the southeastern coast of Korea. Cold water in summer can appear at the sea surface only when there is wind larger than a minimum wind impulse of order $10m^2/sec$.

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Land Generated Waste Load Unit Estimation Based on Land Use Map with LP Optimization (LP 최적화에 의한 토지피복도 기반 토지계 발생부하 원단위 산정)

  • Park, Kyung Ok;Lee, Chang Hee
    • Journal of Wetlands Research
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    • v.18 no.3
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    • pp.226-231
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    • 2016
  • Land Generated Waste Load Unit(LGWLU) estimation based on land use data is required to understand the impact of land use on water quality. The method of estimating LGWLU based on the monitoring data requires a lot of time and manpower. In this study, we propose a method of land pollution unit load estimation based on land use data with LP optimization. Optimization is the process to obtain the best possible optimal solution in a given condition. This study carried out optimization by using excel solver in Microsoft Excel. This study derived LGWLU of BOD, T-N, T-P in Gongju-Si and Seocheon-Gun by using the 2012 land use map made by ministry of environment based on 2010 satellite image. This study about LGWLU estimation is expected to be able to determine more clearly the water pollution caused by land use changes.

Soil Erosion Assessment Using RS/GIS for Watershed Management in Dukchun River Basin, a Tributary of Namgang and Jinyang Lake

  • Cho Byung Jin;Yu Chan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.7
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    • pp.3-12
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    • 2004
  • The need to predict the rate of soil erosion, both under existing conditions and those expected to occur following soil conservation practice, has been led to the development of various models. In this study Morgan model especially developed for field-sized areas on hill slopes was applied to assess the rate of soil erosion using RS/GIS environment in the Dukchun river basin, one of two tributaries flowing into Jinyang lake. In order to run the model, land cover mapping was made by the supervised classification method with Landsat TM satellite image data, the digital soil map was generated from scanning and screen digitizing from the hard copy of soil maps, digital elevation map (DEM) in order to generate the slope map was made by the digital map (DM) produced by National Geographic Information Institute (NGII). Almost all model parameters were generated to the multiple raster data layers, and the map calculation was made by the raster based GIS software, IL WIS which was developed by ITC, the Netherlands. Model results show that the annual soil loss rates are 5.2, 18.4, 30.3, 58.2 and 60.2 ton/ha/year in forest, paddy fields, built-up area, bare soil, and upland fields respectively. The estimated rates seemed to be high under the normal climatic conditions because of exaggerated land slopes due to DEM generation using 100 m contour interval. However, the results were worthwhile to estimate soil loss in hilly areas and the more precise result could be expected when the more accurate slope data is available.

Development study of ground water management system making use of GIS ( Well analysis program, connection program of ground water modeling ) (GIS를 이용한 지하수관리시스템 개발 연구 (관정분석 프로그램, 지하수모델링 연계프로그램))

  • 이병호;김양빈;설민구;송양권;송무영
    • Proceedings of the KSEG Conference
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    • 2002.04a
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    • pp.235-248
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    • 2002
  • Ground water development skill growth and life circumstances improvement increase ground water use. So managerial difficulties and various problems about ground water occur. Poor ground water management organization, lack of management person, thoughtless development add ground water pollution and lack of water volume. And local excessive developments or abandoned well occur. This paper presents ground water management system model making use of GIS and helps effective management by realizing necessary analysis functions in ground water management system and ground management methods. Local information of ground water recorded and development data, site examination data made D/B. And linearment analysis data making use of a satellite image data, hydraulic test data, the quality of water examination data, these local characteristic values made out thematic maps and making use of these data can form elementary data of ground water modeling It makes easy to understand environmental development conditions and pollution source conditions about new ground water development location, linearment growth, DRASTIC, the quality of water examination. Ground water management system making use of these functions can choose right location of ground water.

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Feasibility on Generating Topographic Map Using KOMPSAT (다목적 실용위성(KOMPSAT)을 이용한 지형도 제작의 가능성 분석)

  • 조우석
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.2
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    • pp.281-289
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    • 1998
  • Korea is developing a Korea Multi-Purpose Satellite I (KOMPSAT-1) as one of Korea National Space Program, which will be launched in 1999. The EOC (Electro-Optical Camera) is the primary payload for KOMP-SAT-1. The main mission of EOC is to provide the images for the production of scale maps of Korean territory. This research is focused on methodology and possibility for the production of topographic maps using EOC sensor. Since the imagery from EOC is not yet available, SPOT Level 1A image data which are quite similar to those of EOC, and Intergraph Imagestation (Digital Photogrammetric Workstation) are implemented in the process of sample digital map generation. The sample digital maps generated from SPOT stereoimages were compared and analyzed with the existing 1:50,000 scale digital map produced by National Geography Institute. The feasibility and problem encountered in 1:50,000 scale digital mapping using SPOT stereoimages were presented. Based on results, the feasibility and further research areas for KOMPSAT-EOC in the line of 1:25,000 and 1;50,000 digital mapping were discussed.

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GIS Application for Site Planning

  • Han, Seung-Hee;Lee, Jin-Duk
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.1
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    • pp.53-59
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    • 2009
  • The general urban plan is the plane plan which limits general and uniformed constructions; however, the district unit plan is the solid plan that can leads various constructions by discriminating by plot, housing area and lot. Therefore, for the zone plan, not only the two-dimensional plot information such as plot usage plan, but also the three-dimensional plot information needs to be used to analyze lighting, sewerage and directions. To fulfill such requirements, the information can be gathered using GIS and photogrammetric method for the reasonable and efficient zone plan. In this research, the information about the testing area for the zone plan has been gathered using GIS method, and the three-dimensional model about the area has been built using the satellite image and DEM. As the result, plot usage analysis, direction analyst, water system analysis, and slope analysis has been done and used efficiently to build the district unit plan. Also, after the result after applying the analyzed result to the actual area says this is very appropriate and efficient.

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A Trace of Landcover Change in a Landslide Vulnerable Area (산사태 취약지에서의 토지피복상태 변화 추적)

  • Chun, Ki-Sun;Park, Jae-Kook
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.3
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    • pp.69-76
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    • 2007
  • Kangwondo area is mountainous and landslide is easily happened easily during the rainy period in summer time. Especially, when there is torrential downpour caused by the unusual weather change, there will be greater possibility to see landslide. Another reason behind landslide is the continuous forest fire in these several years. Since the surface of the earth has been changed by the fire, when rainfall comes, landslide just happens easily. Also, it is reported that landcover condition, excepted rainfall condition, is the most effect for determining landslide susceptibility area. In this study, it is determined a landslide vulnerable area and landcover information is extracted from four satellite image(Landsat TM), about the landslide vulnerable area, which is pictured for each year. And which distribution change is analyzed. also, NDVI picture is made and distribution change of vegetation vitality is analyzed to study that change of landcover have a effect on landslide. As a result, could know that forest and NDVI are decreasing in landslide vulnerable area.

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Ship Detection by Satellite Data: Radiometric and Geometric Calibrations of RADARS AT Data (위성 데이터에 의한 선박 탐지: RADARSAT의 대기보정과 기하보정)

  • Yang, Chan-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.10 no.1 s.20
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    • pp.1-7
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    • 2004
  • RADARSAT is one of many possible data sources that can play an important role in marine surveillance including ship detection because radar sensors have the two primary advantages: all-weather and day or night imaging. However, atmospheric effects on SAR imaging can not be bypassed and any remote sensing image has various geometric distortions, In this study, radiometric and geometric calibrations for RADARSAT/SAT data are tried using SGX products georeferenced as level 1. Even comparison of the near vs. far range sections of the same images requires such calibration Radiometric calibration is performed by compensating for effects of local illuminated area and incidence angle on the local backscatter, Conversion method of the pixel DNs to beta nought and sigma nought is also investigated. Finally, automatic geometric calibration based on the 4 pixels from the header file is compared to a marine chart. The errors for latitude and longitude directions are 300m and 260m, respectively. It can be concluded that the error extent is acceptable for an application to open sea and can be calibrated using a ground control point.

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