• Title/Summary/Keyword: Geo-spatial analysis

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Arsenic Distribution and Solubility in Groundwater of Okcheon Area (옥천군 북부 지역 지하수의 비소 분포와 비소 광물의 용해도 특성)

  • Chon, Chul-Min;Kim, Kue-Young;Koh, Dong-Chon;Choi, Mi-Jung
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.4
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    • pp.331-342
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    • 2009
  • Groundwater samples were collected from the bedrock aquifers related with Okcheon metasedimentary rocks. Arsenic (As) concentrations in the samples varied between 0.0051 and 0.887 mg/L, with an average of 0.0248. Cations and anions of groundwaters had no relationship with As contents as well as with spatial distribution of geology in the area. Pyrite, chalcopyrite and arsenopyrite in the core samples of the monitoring wells were identified in thin section, X-ray diffraction (XRD) and electron probe microscope analysis (EPMA). It was suggested that these minerals are responsible for the As in groundwater. The groundwater showed saturations with respect to calcite $(CaCO_3)$, dolomite (CaMg$(CO_3)_2$) and Magnesite $(MgCO_3)$. $HAsO_4{^{2-}}$ activities in the groundwater samples were close to $Ca_3(AsO_4)_2(c)$ and $Mn_3(AsO_4)_2(c)$ solubility isotherms, indicating that the maximum As contents in groundwater are secondly controlled by the precipitation and dissolution of carbonate minerals due to alkaline and oxic nature of the groundwater (pe+pH>10).

Detection of Plastic Greenhouses by Using Deep Learning Model for Aerial Orthoimages (딥러닝 모델을 이용한 항공정사영상의 비닐하우스 탐지)

  • Byunghyun Yoon;Seonkyeong Seong;Jaewan Choi
    • Korean Journal of Remote Sensing
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    • v.39 no.2
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    • pp.183-192
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    • 2023
  • The remotely sensed data, such as satellite imagery and aerial photos, can be used to extract and detect some objects in the image through image interpretation and processing techniques. Significantly, the possibility for utilizing digital map updating and land monitoring has been increased through automatic object detection since spatial resolution of remotely sensed data has improved and technologies about deep learning have been developed. In this paper, we tried to extract plastic greenhouses into aerial orthophotos by using fully convolutional densely connected convolutional network (FC-DenseNet), one of the representative deep learning models for semantic segmentation. Then, a quantitative analysis of extraction results had performed. Using the farm map of the Ministry of Agriculture, Food and Rural Affairsin Korea, training data was generated by labeling plastic greenhouses into Damyang and Miryang areas. And then, FC-DenseNet was trained through a training dataset. To apply the deep learning model in the remotely sensed imagery, instance norm, which can maintain the spectral characteristics of bands, was used as normalization. In addition, optimal weights for each band were determined by adding attention modules in the deep learning model. In the experiments, it was found that a deep learning model can extract plastic greenhouses. These results can be applied to digital map updating of Farm-map and landcover maps.

Land Cover Classification of Coastal Area by SAM from Airborne Hyperspectral Images (항공 초분광 영상으로부터 연안지역의 SAM 토지피복분류)

  • LEE, Jin-Duk;BANG, Kon-Joon;KIM, Hyun-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.1
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    • pp.35-45
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    • 2018
  • Image data collected by an airborne hyperspectral camera system have a great usability in coastal line mapping, detection of facilities composed of specific materials, detailed land use analysis, change monitoring and so forh in a complex coastal area because the system provides almost complete spectral and spatial information for each image pixel of tens to hundreds of spectral bands. A few approaches after classifying by a few approaches based on SAM(Spectral Angle Mapper) supervised classification were applied for extracting optimal land cover information from hyperspectral images acquired by CASI-1500 airborne hyperspectral camera on the object of a coastal area which includes both land and sea water areas. We applied three different approaches, that is to say firstly the classification approach of combined land and sea areas, secondly the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas, and thirdly the land area-only classification approach using atmospheric correction images and compared classification results and accuracies. Land cover classification was conducted respectively by selecting not only four band images with the same wavelength range as IKONOS, QuickBird, KOMPSAT and GeoEye satelllite images but also eight band images with the same wavelength range as WorldView-2 from 48 band hyperspectral images and then compared with the classification result conducted with all of 48 band images. As a result, the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas is more effective than classification approach of combined land and sea areas. It is showed the bigger the number of bands, the higher accuracy and reliability in the reclassification approach referred above. The results of higher spectral resolution showed asphalt or concrete roads was able to be classified more accurately.

The Cross-Sectional Characteristic and Spring-Neap Variation of Residual Current and Net Volume Transport at the Yeomha Channel (경기만 염하수로에서의 잔차류 및 수송량의 대조-소조 변동과 단면 특성)

  • Lee, Dong Hwan;Yoon, Byung Il;Woo, Seung-Buhm
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.5
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    • pp.217-227
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    • 2017
  • The object of this study is to estimate the net volume transport and the residual flow that changed by space and time at southern part of Yeomha channel, Gyeonggi Bay. The cross-section observation was conducted at the mid-part (Line2) and the southern end (Line1) of Yeomha channel for 13 hours during neap and spring-tides, respectively. The Lagrange flux is calculated as the sum of Eulerian flux and Stokes drift, and the residual flow is calculated by using least square method. It is necessary to unify the spatial area of the observed cross-section and average time during the tidal cycle. In order to unify the cross-sectional area containing such a large vertical tidal variation, it was necessary to convert into sigma coordinate system by horizontally and vertically for every hour. The converted sigma coordinate system is estimated to be 3~5% error when compared with the z-level coordinate system which shows that there is no problem for analyzing the data. As a result, the cross-sectional residual flow shows a southward flow pattern in both spring and neap tides at Line2, and also have characteristic of the spatial residual flow fluctuation: it northwards in the main line direction and southwards at the end of both side of the waterway. It was confirmed that the residual flow characteristics at Line2 were changed by the net pressure due to the sea level difference. The analysis of the net volume transport showed that it tends to southwards at $576m^3s^{-1}$, $67m^3s^{-1}$ in each spring tide and neap tide at Line2. On the other hand, in the control Line1, it has tendency to northwards at $359m^3s^{-1}$ and $248m^3s^{-1}$. Based on the difference between the two observation lines, it is estimated that net volume transport will be out flow about $935m^3s^{-1}$ at spring tide stage and about $315m^3s^{-1}$ at neap tide stage as the intertidal zone between Yeongjong Island and Ganghwa Island. In other words, the difference of pressure gradient and Stokes drift during spring and neap tide is main causes of variation for residual current and net volume transport.

CAS 500-1/2 Image Utilization Technology and System Development: Achievement and Contribution (국토위성정보 활용기술 및 운영시스템 개발: 성과 및 의의)

  • Yoon, Sung-Joo;Son, Jonghwan;Park, Hyeongjun;Seo, Junghoon;Lee, Yoojin;Ban, Seunghwan;Choi, Jae-Seung;Kim, Byung-Guk;Lee, Hyun jik;Lee, Kyu-sung;Kweon, Ki-Eok;Lee, Kye-Dong;Jung, Hyung-sup;Choung, Yun-Jae;Choi, Hyun;Koo, Daesung;Choi, Myungjin;Shin, Yunsoo;Choi, Jaewan;Eo, Yang-Dam;Jeong, Jong-chul;Han, Youkyung;Oh, Jaehong;Rhee, Sooahm;Chang, Eunmi;Kim, Taejung
    • 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.

A Basic Study on Spatial Recognition through Poet in Soswaewon Garden (시문을 통해 본 소쇄원의 공간인식에 관한 기초연구)

  • Lee, Won-Ho;Kim, Dong-Hyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.3
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    • pp.38-49
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    • 2015
  • This study aims to contemplated spatial recognition in Soswaewon Garden through garden visitors poetry. It was content analysis in poetry and extract frequency from words based on relationship of author. The results were as follows. First, relationship of authors who wrote Soswaewon Garden poetry was formed in companionship. In the Yang, San-Bo(梁山甫), poetry was written by Song, Soon(宋純), Kim, Un-Geo(金彦据) and Kim, In-Hu(金麟厚) as the central figure. Especially Kim, In-Hu was playing an important role in Soswaewon Garden poetry. He was wrote many of poetry and keep friends with Yang, Ja-Jeong(梁子渟) too. In the Yang, Ja-Jung, relationship of previous generation was sustained. In addition, Ko, Gyeong-Myeong(高敬命) and Kim, Seong-Won and Jeong, Chul(鄭澈) is more closely related than others. Because blood relationship by marriage. In the Yang, Jin-Tae(梁晋泰), He formed a relationship with a celebrity and attend to international activity. Since then Yang, Jin-Tae periord, Yang, Gyeong-Ji(梁敬之) and Yang, Chae-Ji(梁采之) formed relationship of previous generation was sustained. And surrounding people was written poetry as hold a banquet. Second, plant and ornament is a popular object for writing poetry. Bamboo grove and Fine tree with a high frequency of plant element in poetry. Bamboo grove is a typical species of trees in Soswaewon Garden. It was enclosed the Soswaewon Garden. Fine tree was often used target of poetry as a single tree. Meanwhile, ornament of the wall has been used most frequently. Descendants wrote a poem to see it because Kim, In-Hu's poetry was left. This phenomenon is involves respect for the ancient sages with high frequency. In addition, behavior of viewing the landscape was mainly appeared. Third, spatial recognition of Soswaewon Garden can be divided into landscape cognition, behavior cognition and emotional cognition. In a aspect of landscape cognition, early Soswaewon Garden was recognized as a pavilion. That was used garden name to 'Soswaewon Garden' since Yang, Ja-Jung's period. That is to say, Soswaewon Garden expanded from pavilion area surrounded by trees into the whole appearance is equipped garden area. Behavior cognition was consisting drink and enjoys a landscape. In the Yang, San-Bo, authors enjoyed drinking and viewing a landscape besides walking, writing poetry, viewing the moon. But after Yang, San-Bo's period other than drinking and enjoy a landscape has appeared a low frequency. These results were changed from internal place to blood relationship into external place to companionship. In the Yang, San-Bo's emotional cognition was sorrow and yearning about leave to Soswaewon Garden with an idly atmosphere. Pleasant emotion was sustained all generation. And emotion of respect for the ancient sages was appeared since Yang, Cheon-un.

A Way for Creating Human Bioclimatic Maps using Human Thermal Sensation (Comfort) and Applying the Maps to Urban and Landscape Planning and Design (인간 열환경 지수를 이용한 생기후지도 작성 및 도시·조경계획 및 디자인에의 적용방안)

  • Park, Soo-Kuk
    • Journal of the Korean Institute of Landscape Architecture
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    • v.41 no.1
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    • pp.21-33
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    • 2013
  • The purpose of this study is to find applicabilities of human bioclimatic maps, using human thermal sensation(comfort) in summer, with microclimatic in situ data and computer simulation results at the study site of downtown Daegu. This includes the central business district(CBD) area and two urban parks, the Debt Redemption Movement Memorial Park and the 2.28 Park, for urban and landscape planning and design. Climatic data and urban setting information for the analysis of human thermal sensation were obtained from in situ measurement and the geographic information system data. As a result, the CBD had higher air temperature than the parks when the wind speed was low. Relative humidities were opposite to the air temperature. Especially, same directional streets with local wind direction had lower air temperature than streets perpendicular to the wind direction. The most important climatic variable of human thermal sensation in summer was direct beam solar radiation. Also, creating shadow areas would be the most relevant method for modifying hot thermal environments in urban areas. The most effective method of creating shadow patterns was making a tree shadow over a pergola, and the second best one was making a tree shadow on the front of north directional building walls. Moreover, how to plant trees for creating shadow patterns was important as well as what kind of trees should be planted. The results of human thermal sensation were warm to very hot at sunny areas and neutral to warm at shaded ones. At the sunny areas, wide, squared shape areas had a little bit higher thermal sensation than those of narrow streets. The albedo change of building walls 0.15 and ground surface 0.1 could change 1/6 of a sensation level at the shaded areas and 1/3 at the sunny ones. These microclimatic approaches will be useful to find appropriate methods for modifying thermal environments in urban areas.