• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.735-747
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• 2020

Recent advanced UAV (Unmanned Aerial Vehicle) technology supply new opportunities for estimating crop condition using high resolution imagery. We analyzed the diurnal change of reflectance and NDVI (Normalized Difference Vegetation Index) in UAV imagery for crop monitoring in clear day condition. Multi-spectral images were obtained from a 5-band multi-spectral camera mounted on rotary wing UAV. Reflectance were derived by the direct method using down-welling irradiance measurement. Reflectance using UAV imagery on calibration tarp, concrete and crop experimental sites did not show stable by time and daily reproducible values. But the CV (Coefficient of Variation) of diurnal NDVI on crop experimental sites was less than 5%. As a result of comparing NDVI at the similar time for two day, the daily mean average ratio of error showed a difference of 0.62 to 3.97%. Therefore, it is considered that NDVI using UAV imagery can be used for time series crop monitoring.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.92-106
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• 2008

The purpose of this study is to identify land use types and to develop and evaluate biotope maps for Gangseo-Gu (ward) in Busan Metropolitan City, South Korea, using the Degree of Hemeroby. Hemeroby is a measurement concept or tool to assess the magnitude of human impact on ecosystems. Gangseo-Gu is the second largest Gu in Busan and is under strong development pressure. Before the field survey, biotopes were pre-classified based on digital maps, aerial photos and high-resolution satellite images. The method employed in biotope survey and mapping was adopted from the modified method used in Seoul, which carried out the first biotope mapping in Korea in 2000. In the field survey, a comprehensive biotope mapping method was used. The results showed that the total surface area of biotopes in Gangseo-gu was $172,620,207m^2$(42,655 acres) and there were 29 biotope types with 13,631 polygons. The ratio of urban or built-up area 22.6% and the remaining areas were forest and open spaces, of which 22.6% were actual forest areas and 35.6% were paddy fields and other field areas. The Hemeroby Index of Gangseo-gu was 54.7, which suggests that Gangseo-gu has not yet been developed extensively and needs a long-term conservation and coordinated development plan.

• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.867-879
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• 2020

As the era of space technology utilization is approaching, the launch of CAS (Compact Advanced Satellite) 500-1/2 satellites is scheduled during 2021 for acquisition of high-resolution images. Accordingly, the increase of image usability and processing efficiency has been emphasized as key design concepts of the CAS 500-1/2 ground station. In this regard, "CAS 500-1/2 Image Acquisition and Utilization Technology Development" project has been carried out to develop core technologies and processing systems for CAS 500-1/2 data collecting, processing, managing and distributing. In this paper, we introduce the results of the above project. We developed an operation system to generate precision images automatically with GCP (Ground Control Point) chip DB (Database) and DEM (Digital Elevation Model) DB over the entire Korean peninsula. We also developed the system to produce ortho-rectified images indexed to 1:5,000 map grids, and hence set a foundation for ARD (Analysis Ready Data)system. In addition, we linked various application software to the operation system and systematically produce mosaic images, DSM (Digital Surface Model)/DTM (Digital Terrain Model), spatial feature thematic map, and change detection thematic map. The major contribution of the developed system and technologies includes that precision images are to be automatically generated using GCP chip DB for the first time in Korea and the various utilization product technologies incorporated into the operation system of a satellite ground station. The developed operation system has been installed on Korea Land Observation Satellite Information Center of the NGII (National Geographic Information Institute). We expect the system to contribute greatly to the center's work and provide a standard for future ground station systems of earth observation satellites.