• 농업과학연구
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• 제47권4호
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• pp.1097-1107
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• 2020

Assessment of soil carbon stock is essential for climate change mitigation and soil fertility. The digital soil mapping (DSM) is well known as a general technique to estimate the soil carbon stocks and upgrade previous soil maps. The aim of this study is to calculate the soil carbon stock in the top soil layer (0 to 30 cm) in Jeolla Province of South Korea using the DSM technique. To predict spatial carbon stock, we used Cubist, which a data-mining algorithm model base on tree regression. Soil samples (130 in total) were collected from three depths (0 to 10 cm, 10 to 20 cm, 20 to 30 cm) considering spatial distribution in Jeolla Province. These data were randomly divided into two sets for model calibration (70%) and validation (30%). The results showed that clay content, topographic wetness index (TWI), and digital elevation model (DEM) were the most important environmental covariate predictors of soil carbon stock. The predicted average soil carbon density was 3.88 kg·m-2. The R2 value representing the model's performance was 0.6, which was relatively high compared to a previous study. The total soil carbon stocks at a depth of 0 to 30 cm in Jeolla Province were estimated to be about 81 megatons.

• 한국제4기학회지
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• 제22권2호
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• pp.23-27
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• 2008

• Spatial Information Research
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• 제10권4호
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• pp.533-550
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• 2002

Soil organic matter (SOM) content and other physical soil properties were extracted from a digital soil database, the Soil Survey Geographic (SSURGO) database, to map the amount of SOM and determine its relationship with topographic positions in floodplain areas along a river basin in Douglas County, Kansas. In the floodplains, results showed that slope and SOM content had a significant negative relationship. Soils near river channels were deep and nearly level, and they had the greatest SOM content in the floodplain areas. For the whole county, SOM content was influenced primarily by soil depth and percent SOM by weight. Among different slope areas, soils on mid-range slopes (10-15%) and ridgetops had the highest SOM content because they had relatively high percent SOM content by weight and very deep soils, respectively. SOM content was also significantly variable among different land cover types. Forest/woodland had significantly higher SOM content than others, followed by cropland, grassland, and urban areas.

• 한국지형학회지
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• 제23권3호
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• pp.67-78
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• 2016

Soil carbon(C) is an essential property for characterizing soil quality. Understanding spatial patterns of soil C is particularly limited for mountain areas. This study aims to predict the spatial pattern of soil C using terrain analysis in a steep mountainous area. Specifically, model performances and prediction uncertainties were investigated based on the number of resampling repetitions. Further, important predictors for soil C were also identified. Finally, the spatial distribution of uncertainty was analyzed. A total of 91 soil samples were collected via conditioned latin hypercube sampling and a digital soil C map was developed using support vector regression which is one of the powerful machine learning methods. Results showed that there were no distinct differences of model performances depending on the number of repetitions except for 10-fold cross validation. For soil C, elevation and surface curvature were selected as important predictors by recursive feature elimination. Soil C showed higher values in higher elevation and concave slopes. The spatial pattern of soil C might possibly reflect lateral movement of water and materials along the surface configuration of the study area. The higher values of uncertainty in higher elevation and concave slopes might be related to geomorphological characteristics of the research area and the sampling design. This study is believed to provide a better understanding of the relationship between geomorphology and soil C in the mountainous ecosystem.

• 한국농공학회논문집
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• 제46권7호
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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.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.22-29
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• 2003

This research aims at investigation of accuracy potential of RTK(Real-Time Kinematic) GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On The Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only 2% was achieved. This indicates that the coastal mapping. As a result, it has been revealed that every possible noise in surveying could be corrected and the accuracy could be improved. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM(Digital Terrain Model) can be also constructed for the harbor reclamation, the dredging, and the variation of soil movement in a river.

• 한국해양공학회지
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• 제17권3호
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• pp.13-20
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• 2003

This research aims at investigation of accuracy potential of RTK(Real-Time Kinematic) GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On The Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only $2\%$ was achieved. This indicates that the coastal mapping. As a result, it has been revealed that every possible noise in surveying could be corrected and the accuracy could be improved. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM(Digital Terrain Model) can be also constructed for the harbor reclamation, the dredging, and the variation of soil movement in a river.

• 한국지반환경공학회 논문집
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• 제17권3호
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• pp.21-26
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• 2016

주문진 표준사와 사우디 아라비아의 Ras Al Khair 사질토 입자의 형상에 대한 분석을 실시하였다. 광학현미경을 사용하여 200배 확대하여 해상도 $640{\times}320$으로 디지털 이미지를 촬영하였다. 사질토 입자의 디지털 이미지를 영상 처리를 통해 입자 경계면의 좌표를 추출하였다. 추출한 입자의 경계면 좌표를 복소 평면에 도시하고, 극형식으로 변환 후 퓨리에 변환을 실시하였다. 퓨리에 변환을 통해 추출된 각각의 계수 값들은 입자 형상의 특징을 반영하며, 좌표의 기준점 이동에 대해 불변하는 값으로 사질토 입자의 이미지에 대해 좌표의 기준점과 회전등에 관계없이 항상 같은 값을 갖게 되어 입자의 형상 분석에 적합하다. 각각의 계수 값을 입자의 등가 반경으로 정규화하여 퓨리에 기술자를 추출하여 입자의 형상을 정량적으로 분석하였다. -3에서 +3의 범위에 해당되는 주요 퓨리에 기술자들을 분석한 결과 주문진 표준사 입자의 경우 신장(elongation)이 가장 두드러진 형상의 특징이었으며 그다음으로는 비대칭성(asymmetry)이 두드러진 특징이었다. Ras Al Khair 사질토의 형상도 주문진 표준사와 같은 형상 특징을 나타냈다. 또한 퓨리에 기술자 분석 결과 작은 구조가 전체 구조와 비슷한 형태로 되풀이되는 프랙탈의 미세구조 특성이 나타나는 것으로 판단되었다. 해상도 $640{\times}320$과 해상도 $160{\times}80$의 주문진 표준사의 디지털 이미지를 비교한 결과 -3에서 +3에 해당되는 주요 퓨리에 기술자에 대해서는 해상도가 크게 영향을 미치지 않는 것으로 나타났으나 텍스쳐 분석에는 영향을 미치는 것으로 나타났다.

• 디지털콘텐츠학회 논문지
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• 제19권7호
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• pp.1423-1431
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• 2018

사물인터넷 기술은 농업, 낙농업 등의 기술에 적용되어 도시에서도 간편하고 손쉽게 농작물을 재배하는 것을 가능하게 한다. 특히, 농업 부문에서 재배작물의 생장환경에 맞도록 지능적으로 판단하고 제어하는 사물인터넷 기술이 발전되고 있다. 본 논문에서는 지능형 사물인터넷을 이용하여 식물의 수분 공급 주기를 학습함으로써 식물의 생장 환경을 예측하는 방법을 제안한다. 제안된 시스템은 토양 수분량의 수분단계를 지도 학습으로 찾아내고, 측정된 수분단계를 기반으로 수분 공급의 규칙을 찾아낸다. 이러한 규칙을 기반으로 수분 공급 주기를 예측하고, 미디어를 이용하여 출력함으로써 사용자가 사용하기에 편리하도록 구현하였다. 또한, 센서가 측정하는 값의 오차를 줄이기 위하여 식물간에 서로 정보를 교환함으로써 오류가 있는 경우의 값을 보완해 가면서 예측의 정확도를 높였다. 생장 환경 예측 시스템의 성능을 평가하기 위하여 토양 수분 공급량이 현격히 차이가 있는 여름과 겨울로 나누어서 실험하였으며, 정확도가 높음을 검증하였다.

• 한국토양비료학회지
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• 제45권6호
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• pp.1164-1172
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• 2012

급격한 토지이용의 변화가 진행되고 있는 수도권 인근의 고양시, 남양주시, 용인시를 대상으로 고해상도 영상과 수치지도를 활용하여 논, 밭, 시설재배지, 과수원의 면적과 형상, 이용 현황을 파악하기 위한 농경지 지도를 작성하여 기존 수치지도와 비교한 결과 기존 수치지도에 비해 농경지의 이용 현황을 보다 세부적으로 정확하게 분류할 수 있었다. 또한, 농경지 지도와 수치 지적도의 농경지 부분을 중첩하여 '07년 토지이용도로 갱신하고 '99년에 작성된 토지이용도와 비교한 결과 3개 시 모두 조사기간 동안 논 면적이 3,000~5,000 ha 정도 크게 감소한 것으로 나타났으며, 밭과 과수원도 논과 함께 주거지로 전용되면서 감소하는 추세였다. 그러나 집약적인 재배가 가능하여 고소득이 기대되고 다른 지목으로 변경이 용이한 시설재배지의 경우에는 면적이 비슷하거나 증가한 경향을 보였다. 향후 고해상도 영상을 활용한 농경지 지도의 확대 구축과 이를 활용한 토지이용도 제작은 토양 조사 등 각종 조사 사업의 최신 자료로 활용 될 수 있을 뿐 아니라, 정확한 경지면적 산출을 통해 농업통계 및 농업정책 자료로써 효율적인 경지관리에 활용될 수 있을 것으로 판단된다.