• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제4권3호
• /
• pp.149-156
• /
• 2000

This study presents an investigation of the changes that have occurred in the coastal ocean area of Kwangyang Bay located in the South Coastal region of Korea using remote sensing data based on Landsat Thematic Mapper (TM) multispectral digital data from 1988 and 1996. The coastal changes were detected using the digital histogram method and vector trace method. All the images were preprocessed, i.e. geometrically corrected, before the training set selection. when comparing the histograms of 7-band TM data, it was found that the band 5 image exhibited two critical Digital Number(DN) peaks, thereby indicating new coastal water and coastal land data. Based on this information, the coastal ocean area of the band 5 image was calculated using the vector tracing method supported by a CAD program. The result shows that the coastal ocean area decreased by about 5 % between 1988 to 1994. Accordingly, this gives a strong indication that the continuing land development will have a serious impact on the ecosystem of Kwangyang Bay.

• 대한원격탐사학회지
• /
• 제28권6호
• /
• pp.597-609
• /
• 2012

Leaf area index (LAI) is important in explaining the ability of the crop to intercept solar energy for biomass production and in understanding the impact of crop management practices. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of IKONOS, Landsat TM, and MODIS satellite images using empirical models and demonstrates its use with data collected at Missouri field sites. LAI data were obtained several times during the 2002 growing season at monitoring sites established in two central Missouri experimental fields, one planted to soybean (Glycine max L.) and the other planted to corn (Zea mays L.). Satellite images at varying spatial and spectral resolutions were acquired and the data were extracted to calculate normalized difference vegetation index (NDVI) after geometric and atmospheric correction. Linear, exponential, and expolinear models were developed to relate temporal NDVI to measured LAI data. Models using IKONOS NDVI estimated LAI of both soybean and corn better than those using Landsat TM or MODIS NDVI. Expolinear models provided more accurate results than linear or exponential models.

• 한국측량학회지
• /
• 제21권3호
• /
• pp.261-267
• /
• 2003

두 시기의 분류영상으로부터 추출된 각각의 정보를 지리정보의 속성정보로 입력하여 지리정보시스템의 한 매개변수로 이용함으로써 두 시기의 지표변화정보를 동시에 추출할 수 있다. 따라서 본 연구에서는 지표피복 정보를 획득할 수 있는 원격탐사기법과 지리정보시스템의 장점을 활용하여 토지이용 변화양상과 더불어 지표의 효율적인 관리 및 개발을 위한 기초자료를 제시하고자 하였다 지표변화정보 추출에 관한 연구를 수행한 결과 기존의 영상분류방법보다 영상정보처리를 쉽게 할 수 있어 각 화소에 대한 지표의 변화과정을 쉽게 알 수 있었다.

• 한국농공학회논문집
• /
• 제58권2호
• /
• pp.53-63
• /
• 2016

Monitoring of cyanobacteria bloom in reservoir systems is important for water managers responsible of water supply system. Cyanobacteria affect the taste and smell of water and pose considerable filtration problems at water use places. Harmful cyanobacteria bloom in reservoir have significant economic impacts. We develop a new method for estimating the cyanobacteria bloom using Landsat TM and ETM+ data. Developed model was calibrated and cross-validated with existing in situ measurements from Daecheong Reservoir's Water Quality Monitoring Program and Algae Alarm System. Measurements data of three stations taken from 2004 to 2012 were matched with radiometrically converted reflectance data from the Landsat TM and ETM+ sensor. Stepwise multiple linear regression was used to select wavelengths in the Landsat TM and ETM+ bands 1, 2 and 4 that were most significant for predicting cyanobacteria cell number and bio-volume. Based on statistical analysis, the linear models were that included visible band ratios slightly outperformed single band models. The final monitoring models captured the extents of cyanobacteria blooms throughout the 2004-2012 study period. The results serve as an added broad area monitoring tool for water resource managers and present new insight into the initiation and propagation of cyanobacteria blooms in Daecheong reservoir.

• 환경영향평가
• /
• 제6권1호
• /
• pp.55-66
• /
• 1997

This study summarizes the use of satellite data to detect the change of southwestern coastal wetlands in Korea. The images used for this study were two Landsat Thematic Mapper(TM) images (June 12, 1984 & June 2, 1992). TM images were used to classify such different types of wetlands as aquatic bed, nonaquatic bed and other land use in the region. Then it, was possible to a) determine the status of wetlands using image classification products, and b) detect the changes of various types of wetlands influenced by both human and nature. The results from spatiotemporal analysis showed that approximately 120 lad of coastal wetlands were lost from the year of 1984 to 1992. 71 % of the lost wetlands were converted to the reclaimed land. This loss of wetlands has been causing the profound environmental impacts. It has been successfully proved that satellite data are very effective for spatiatemporal change analysis, especially for that of coastal wetlands.

• 대한원격탐사학회지
• /
• 제3권1호
• /
• pp.1-10
• /
• 1987

The study was performed to recognize the most preferable spectral chennels for discriminating geological materials using the portable radiometer. The portable radiometer covers the visible and short infrared regions from approximately 0.4 to 2.5 microns which are coincided with Landsat TM, and the rock samples used for the study are pyrophylites, andesites, granite, granodiorite and silicified sedimentary rocks which are collected in Yangsan-Dongrae fault area. The analysis of the rock sample provides a preliminary basis for determining the wavelength regions showing diagnostic spectral features and for discriminating hydrothermal altered rocks from the unaltered rocks. The measurement of spectral of spectral reflectance for the rock samples was carried out in the laboratory which environment condition such as temperature, light sources, and humidity are constant. The analysis of the measured data was based on correlation between the reflectance value of the rock samples, and the follow discriptions are output of the study. 1) Pyrophyllite shows absorption at 0.83 $\mu\textrm{m}$ due to the oxidation of pyrite, and absorption at 2.22 $\mu\textrm{m}$ due to OH. 2) The altered rocks have generally higher reflectance than the unaltered rocks. 3) The ratio mesurement of pyrophyllites shows strong absorption at band 5/6 and band 6/4(in Landsat TM 5/7, 7/4). The ratio 1/5(Landsat TM 1/5) may be useful to discriminate andesite from the granite.

• 전자공학회논문지B
• /
• 제31B권8호
• /
• pp.147-159
• /
• 1994

The performance of the improvement method of spatial resolution for satellite images based on the generalized inverse matrix is superior to the conventional methods. But, this method calculates the coefficient values for extracting the spatial information from the relation between a small pixel and large pixels. Accordingly it has the problem of remaining the blocky patterns at the result image. In this paper, a new generalized inverse matrix method is proposed which is different in the calculation method of coefficient values for extracting the spatial information. In this proposed metod, it calculates the coefficient values for extracting the spatial information from the relation between a small pixel and small pixels. Consequently it can improve the spatial resolution more efficiently without remaining the blocky patterns at the result image. The effectiveness of the proposed method is varified by simulation experiments with real TM image data.

• 한국측량학회지
• /
• 제11권1호
• /
• pp.55-60
• /
• 1993

자연 생태계의 일부분으로 발생한 삼림은 공기를 맑게하고 수자원을 보존하며, 번식과 멸종의 방지, 휴식공간 제공 그리고 인간생활 환경을 형성하고 보존시키는 역할을 수행한다. 본 연구에서 원격탐사 자료를 이용하여 삼림식생을 분류한 것은 침염수, 활엽수, 농경지 및 초지, 물의 네 가지로 삼림식생정보를 분류하였다. TM 수치영상을 컴퓨터를 이용하여 분류할 경우, 물지역의 특성 값은 제 4밴드에서 7-13 D.N으로 나타났다. 그러나 침엽수, 활엽수, 농경지 및 초지는 모두 비슷한 특성 값이 나타나므로 화상처리를 해야했다. 화상처리를 제 2밴드와 제 3밴드를 합성한 영상을 비연산처리한 결과, 제 3밴드로부터 활엽수 지역은 72-91의 D.N으로 나타나고, 제 1밴드에서의 침엽수 지역은 l18∼136, 제 3밴드에서의 농경지 및 초지는 96-120의 D.N에서 일치하였다. 또한 최대 우도법으로 분류한 결과와 TM 수치영상의 현지답사에 대한 비교오차를 구한 결과 침엽수, 활엽수, 농경지와 초지 및 물에서 각각 －7.43%, ＋1.89%, ＋7.58%, -2.04%의 분류 정확도를 얻었다. 결론적으로 이 결과는 원격탐사 자료를 이용한 삼림식생분류가 매우 유용한 것임이 입증되었다.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2003년도 International Symposium on Clean Environment
• /
• pp.33-36
• /
• 2003

Principal component analysis (PCA) was used to improve image classification by the unsupervised classification techniques, the K-means. To do this, I selected a Landsat TM scene of Jeju Island, Korea and proposed two methods for PCA： unstandardized PCA (UPCA) and standardized PCA (SPCA). The estimated accuracy of the image classification of Jeju area was computed by error matrix. The error matrix was derived from three unsupervised classification methods. Error matrices indicated that classifications done on the first three principal components for UPCA and SPCA of the scene were more accurate than those done on the seven bands of TM data and that also the results of UPCA and SPCA were better than those of the raw Landsat TM data. The classification of TM data by the K-means algorithm was particularly poor at distinguishing different land covers on the island. From the classification results, we also found that the principal component based classifications had characteristics independent of the unsupervised techniques (numerical algorithms) while the TM data based classifications were very dependent upon the techniques. This means that PCA data has uniform characteristics for image classification that are less affected by choice of classification scheme. In the results, we also found that UPCA results are better than SPCA since UPCA has wider range of digital number of an image.

• 한국지리정보학회지
• /
• 제17권4호
• /
• pp.1-9
• /
• 2014

중국의 사막화로 인해 발생된 황사 방지대책의 일환으로 우리나라의 전문시민단체와 기업에서는 2008년부터 매년 황사발생 원인지역에 나문재를 파종하고 있다. 이와 관련하여 황사발생 원인지역의 녹지 환경 조성 계획을 위해서는 대상지의 녹지화 현황 분석이 요구된다. 따라서 본 연구에서는 녹지 환경의 조성 현황을 파악하고 분석하기 위해 Landsat 5 TM 위성영상과 Landsat 8 위성영상을 기반으로 영상분류를 통한 녹지 환경을 분석하였으며, 소금사막 내부의 상세한 녹지 환경 및 식생지수를 파악하기 위해 NDVI를 이용한 분석을 수행하였다. 그 결과, 2009년에서 2011년 사이에는 소금사막과 나대지가 대폭 감소하고 녹지가 증가하는 녹지화가 효율적으로 진행된 반면, 2011년에서 2013년 사이에는 녹지 면적이 급격히 감소하고 나대지가 증가한 것으로 나타났다. 이를 통해 2011년 이후 녹지 환경 조성에 어려움이 있는 것을 알 수 있었으며, 향후 녹지화 사업 시 위성영상을 이용한 사업 수행이 필요할 것으로 판단된다.