• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.1-9
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• 2014

The interest group and corporation in Korea have cultivated Suaeda grass in the source area every year as a plan to prevent the yellow dust due to Chinese desertification. It needs the afforestation analysis about the research area to plan the greenbelt environment development in the region of yellow dust origin. Thus, this research analyzed the greenbelt environment based on Landsat 5 TM satellite image and Landsat 8 image to grasp and analyze the present of greenbelt environment development. And this research analyzed the inside of the salt desert to understand the detailed greenbelt environment and vegetation index. As a result, it represents that the afforestation was accomplished efficiently between 2009 and 2011, while the greenbelt area was decreased rapidly and bare soil was increased between 2011 and 2013. Through these results, we could recognize that it is in trouble about the greenbelt environment development after 2011 and it needs the project implementation using satellite image when the next afforestation project is planned henceforth.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.7
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• pp.723-728
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• 2016

This study is analyzed the optical property of red tide pixel by using Landsat-7 ETM+, Landsat-8 OLI and COMS/GOCI image. In order to sample red tide pixel, Landsat-7, 8 true color image were used and obtained coordinate of red tide pixel in the true color image. Normalized water leaving radiance(nLw) and absorption coefficient were obtained from GOCI image in the same coordinate of the true color image. When red tide was not occurred the main absorption range was 412nm and 660nm but when red tide occurred it was 660nm and absorption coefficient in 412nm are drastically reduced. It made no difference of nLw spectrum between red tide pixel and non red tide pixel in nLw, but the absolute value of nLw was low than non red tide pixel, especially 660nm and 680nm wavelength sharply decrease.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.2 s.36
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• pp.63-68
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• 2006

Although it is more recommended to use satellite images for an accurate understanding of the natural environment over a large area, what should proceed obtaining such satellite images is to make basic model equations based firmly upon the on-land experiments and field experiments. It may be more accurate and objective to investigate correlations between satellite images and actual water quality factors obtained for the same area. Thus, this study was conducted in order to determined which band of Landsat ETM+ images is appropriate to estimate the density of chlorophyll-a in a closed laboratory without atmospheric interference, using pure water and sea water. As a result of this study, it was found that the best band that exhibited the highest degree of correlations among the compounded bands rated (B3-B4)/B2 in pure water and (B2+B4)/B3 in sea water. The correlation coefficient here is 0.9747 and 0.9892 respectively. Thus, compounding this band ran be quite useful for estimation density of Chlorophyll-a using Landsat ETM+ image data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.219-225
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• 2008

There are many problems in monitering environmental change around of nuclear power station, because interesting area is coastal and relatively large. The ground resolution of Landsat ETM+ imagery is high (30 m), but this imagery does not have enough informations for conducting atmospheric correction in evaluating sea surface temperatures. On the other hand, while it is possible to conduct atmospheric correction using MODIS imagery with it's two infrared bands, it's resolution is relatively low (1 km). Therefore, atmospheric corrected high resolution temperature information can be obtained from these two satellite images. In this study, digital numbers of Landsat ETM+ data in interesting area are georeferenced, converted to effective temperatures based on radiance value, and then the atmospheric correction is conducted using MODIS data. As a result, about $3.5^{\circ}C$ temperature differences were detected in comparing sea surface temperature of the surrounding area of Uljin nuclear power station with it of the same area located 5km far east.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.2
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• pp.98-106
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• 2016

Remote sensing is an efficient technology for observing and monitoring the land surfaces inaccessible to humans. This research proposes a methodology for improving the accuracy of the land cover classification using the Landsat-8 operational land imager(OLI) image. The proposed methodology consists of the following steps. First, the normalized difference vegetation index(NDVI) and normalized difference water index(NDWI) images are generated from the given Landsat-8 OLI image. Then, a new image is generated by adding both NDVI and NDWI images to the original Landsat-8 OLI image using the layer-stacking method. Finally, the maximum likelihood classification(MLC), and support vector machine(SVM) methods are separately applied to the original Landsat-8 OLI image and new image to identify the five classes namely water, forest, cropland, bare soil, and artificial structure. The comparison of the results shows that the utilization of the layer-stacking method improves the accuracy of the land cover classification by 8% for the MLC method and by 1.6% for the SVM method. This research proposes a methodology for improving the accuracy of the land cover classification by using the layer-stacking method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3B
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• pp.233-242
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• 2010

SEBAL (Surface Energy Balance Algorithm for Land) developed by Bastiaanssen (1995) is an image-processing model comprisedof twenty-five sub models that calculates spatial evapotranspiration (ET) and other energy exchanges at the surface. SEBAL uses image data from Landsat or other satellites measuring thermal infrared radiation, visible and near infrared. In this study, the model was applied to Gyeongancheon watershed, the main tributary of Han river Basin. ET was computed on apixel-by-pixel basis from an energy balance using 4 years (2001-2004) Landsat and MODIS images. The scale effect between Landsat (30 m) and MODIS (1 km) was evaluated. The results both from Landsat and MODIS were compared with FAO Penman-Monteith ET. The absolute errors between satellite ETs and Penman-Monteith ET were within 12%. The spatial and temporal characteristics of ET distribution within the watershed were also analyzed.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.322-322
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• 2011

지표에서의 토양수분은 작은 구성비를 가짐에도 불구하고 여러 수문 현상을 연계하는 매우 중요한 인자로써 최근 연구가 활발하게 진행되고 있다. 토양수분은 침투나 침루를 통하여 강우와 지하수를 연결하는 기능을 함과 동시에 강우사상에 따른 유출특성에 직접적인 영향을 미치며 증발산을 통하여 에너지 순환을 연결하는 기능을 하는 인자로 기후변화와 인간의 활동에 의해 영향을 받는다. 지난 수십 년간 산림개간과 도시화는 토지이용의 변화를 초래하여 토지피복의 변화를 초래하였다. 도시화는 불투수층을 증가시켰고, 산림개간으로 산림이 농장으로 변하여 침투율을 감소시켜 유출률의 증가를 초래하였다. 이처럼 토지피복의 변화는 토양수분의 변화에 직접적인 영향을 미친다. 본 연구에서는 토지피복 분류를 위해 구름의 영향이 적은 Landsat TM 영상을 사용하여 청미천 유역의 토지피복을 분류하여 토지피복도를 작성하였다. 청미천 유역은 현재 국제수문관측사업(IHP)의 일환으로 체계적인 수문관측이 진행되고 있는 지점으로, 추후 인공위성 영상을 통해 산정한 토양수분 자료를 비교할 수 있는 유역이다. Landsat TM 영상은 2009년 5월 23일에 관측된 115-34(path row) 영상으로 구름이 거의 없는 날의 자료를 사용하였다. 다중 스펙트럴 위성영상인 Landsat TM 영상은 30m 공간해상도로써 토지피복분류와 식생 등의 정보를 추출하는데 적합한 것으로 알려져 있다. 청미천 유역의 위성영상에 대하여 영상의 전처리 과정을 거쳐 무감독분류와 감독분류기법을 적용하여 토지피복을 분류하였다. 분류한 토지피복도는 국토해양부에서 국가수자원관리 종합정보시스템(WAMIS) 을 통하여 제공되는 토지피복도와 비교하였다.

• Proceedings of the KSRS Conference
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• 2001.03a
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• pp.9-14
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• 2001

오랜 기간동안 진행되는 사회간접자본 건설의 진행 상황을 관측하는 것은 대규모 공사의 종합적인 관리를 위해 필수불가결한 요소이다. 동북아 지역의 중추 공항 기능을 담당할 영종도 국제공항의 공사진행 과정을 관측하기 위하여 인공위성 영상 자료가 활용되었다. 바다위에 건설되는 공항의 특성으로 인하여 방조제 건설과 매립공사가 수행되었다. 활주로, 유도로, 여객터미널과 복합교통센터 등이 건설되었으며, 공항의 건설로 산림이 훼손되고 양식장과 염전이 매립되는 것이 관측되었다. 이러한 공항공사의 진척상태를 분석하기 위해서 시계열 Landsat TM 영상을 사용하였으며, 타 위성영상에서는 공항의 공사현황이 어느정도 분석가능한지를 가늠하기 위해서 KOMPSAT EOC, IRS-1C PAN, RADARSAT SAR 영상이 활용되었다. 시계열 Landsat TM 영상에서는 공항 부지의 매립 진척 현황과 산림의 벌채 등을 잘 분석할 수 있었다. KOMPSAT EOC 과 IRS-1C PAN 영상은 높은 공간해상력으로 건설에 사용된 가건물과 같은 세부적인 시설물을 관측할 수 있었다. 15m PAN 영상을 제공하는 Landsat ETM은 IHS 합성 후 분석하였는데, 기존의 TM 영상에서 분류하지 못했던 방조제의 도로와 성토를 구분할 수 있었다. RADARSAT SAR 영상에서는 광학영상에서 볼 수 없었던 독특한 정부 를 얻을 수 있었다.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.735-743
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• 2001

CN procedure has been proven to be useful method for evaluating the effects of changes in land-use and treatment on hydrology. In this study, the use of Landsat multi-spectral image was investigated for analyzing the land-use distribution. From the Landsat data, forest areas were classified according to the density of trees. Watershed CN's were calculated to analyze the effects of the density of trees and soil cover types on direct runoff. According to the results, the density of trees had a little effect while soil cover types had a large effect on CN, From the comparison of estimated runoffs from CN method with observed runoffs, detailed soil cover map provides improved results.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.399-406
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• 2013

The quality of satellite imagery should be improved and stabilized to satisfy numerous users. The radiometric characteristics of an optical sensor can be a measure of data quality. In this study, a band aggregation technique and spectral response function of hyperspectral images are used to simulate multispectral images. EO-1 Hyperion and Landsat-8 OLI images acquired with about 30 minutes difference in overpass time were exploited to evaluate radiometric coefficients of OLI. Radiance values of the OLI and the simulated OLI were compared over three subsets covered by different land types. As a result, the index of agreement shows over 0.99 for all VNIR bands although there are errors caused by space/time and sensors.