• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.949-960
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• 2003

The resolution issue of wetness index with relaxation of the steady state assumption is explored on the platform of Digital Elevation Model (DEM). The variabilities of the quasi-dynamic wetness index and the dynamic wetness index are discussed on the base of the spatial and statistical aspects depending upon resolutions of DEM and the drainage time. The organization patterns of the wetness index can be observed upon various drainage times and pixel size. The transient behaviour of wetness patterns of the Sulmachun watershed are shown in the relatively short drainage time. The statistical analysis of the quasi-dynamic and dynamic wetness analysis provide the convergence of analysis results to the steady state characteristics later than 10,000 hours drainage time. The probability density functions of the quasi-dynamic and the dynamic wetness index shows the existence of the threshold pixel size of DEM which provide stability and consistency in the computation result of these two wetness index.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.937-941
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• 2007

For Hydrologic analysis of the river, the exact Dividing Watershed and Hydrologic-Topographical Parameters affect enormously Hydrologic analysis of the river basin. Therefore the extraction of Hydrologic-Topographical Parameters as well as Dividing Watershed are stiuied by several ways. However the definite standard of all those means are not settled. Recently GIS is applied to the field of water resources so that we can divide Watershed and calculate Hydrologic-Topographical Parameters of the targeted area easily and objective way for using DEM. Thanks to DEM, we don't have to spend much time as we did before. However other problems are generated such as the parameter value is changed by the precision of established NGIS(National Geographic Information System), etc. In this study, using GIS which is popular recently, we suggested efficient extract method of Hydrologic-Topographical Parameters SCS(Soil Conservation Service) CN(Curve Number) in watershed.

• KSCI Review
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• v.14 no.2
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• pp.147-152
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• 2006

Data size of moving current GIS great exponentially from 2D to 3D and the processing speed becomes slow thereby and user's real time rendering request is growing. Have problem that time and expense to process data of bulky quantity produce constraint condition of the processing speed. third dimension processing skill, virtual reality processing skill etc. and third dimension GIS about space data of bulk much overmuch to materialize. In this paper DEM data that acquire from satellite or aviation solve these problem embody virtual city in web save topography information that visualization to 3D visualization by VRML, and use modelling tool and acquire 3D campus information for building and road. 3D information acquired this to express texture and natural gifts that have truth stuff more to thing through near texture mapping work 3D imagination illustration of web based embody can.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.29-37
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• 2017

In this study, we analyzed the impacts of land surface characteristics on spatially and temporally distributed soil moisture values at the Yongdam and Soyang-river dam watersheds in 2014 and 2015. The soil moisture, NDVI (Normalized Difference Vegetation Index) and temperature values at the spatio-temporal scales were estimated using satellite-based MODIS (MODerate Resolution Imaging Spectroradiometer) products. Then the Pearson correlations between soil moisture and land surface characteristics (NDVI, temperature and DEM-digital elevation model) were estimated and analyzed, respectively. Overall, the monthly soil moisture values at the time step were highly influenced by the precipitation amounts. Also, the results showed that the soil moisture has the strong correlation with DEM while the temperature was inversely correlated with the soil moisture. However the monthly correlations between NDVI and soil moisture were highly varied along the time step. These findings indicated that water loss near the land surface are highly occurred by soil and plant activities as evapotranspiration and infiltration during the no/less precipitation period. But the high precipitation amounts reduce the impacts of land surface characteristics because of saturated condition of land surface. Thus these results demonstrated that soil moisture values are highly correlated with land surface characteristics. Our findings can be useful for water resources/environmental management, agricultural drought, etc.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.159-172
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• 2014

As greenhouse gas emissions have been increasing in the world, global warming is being recognized as a cause of the global problems like climate change. This is closely associated the fossil fuels. Thus renewable energy has been brought to the attention of many people as the upcoming alternative energy source to cope with the fossil drain and increased environmental regulations. Especially, the solar energy among renewable energy has drastically increased. In this study, we calculate on daylight ratio about the solar energy for buildings based on digital surface model. The digital surface model was made using the spatial information data. And it was simulated the shadow analysis using SAS. Therefore, it was suitable places to utilize the solar energy in the Gyeongsan city. Consequently, the daylight ratio was considered important factor to select region of the industry of the solar light power generation.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.519-528
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• 2016

Frequently torrential rain is occurred by climate change and urbanization. Urban is formed with road, residential and underground area. Without detailed topographic flooded analysis consideration can take a result which are wrong flooded depth and flooded area. Especially, flood analysis error of population and assets in dense downtown is causing a big problem for establishments and disaster response of flood measures. It can lead to casualties and property damage. Urban flood analysis is divided into sewer flow analysis and surface inundation analysis. Accuracy is very important point of these analysis. In this study, to confirm the effects of the elevation data precision in the process of flooded analysis were studied using 10m DEM, LiDAR data and 1:1,000 digital map. Study area is Dorim-stream basin in the Darim drainage basin, Sinrim 3 drainage basin, Sinrim 4 drainage basin. Flooding simulation through 2010's heavy rain by using XP-SWMM. Result, from 10m DEM, shows wrong flood depth which is more than 1m. In particular, some of the overflow manhole is not seen occurrence. Accordingly, detailed surface data is very important factor and it should be very careful when using the 10m DEM.

• Journal of the Korean Geographical Society
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• v.44 no.1
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• pp.31-55
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• 2009

This research aims 1) to characterize the spatial distribution of low relief landforms (plains) via analyses of a Digital Elevation Model (DEM), 2) to classify plains according to morphological and genetic similarity, and 3) to develop a model to explain forming processes of plains in the Korean peninsula. Plains can easily be separated from high relief mountaneous areas by analyzing the DEM. The overall morphological and locational characteristics of plains can be categorized into lava plains, fluvial-marine plains, erosional plains, intermontane basins, and higher ground plains. It is concluded that the characteristic of each plain type is decided by base-level changes caused by tectonic uplift and sea-level changes, and topological relationship of different rock types. Different plain types do not exist independently, but connected with each others along stream networks. The model developed is able to combine the morphological characteristics of plains with the channel network to conceptualize characteristics and development pathways of plains in the Korean Peninsula.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.277-292
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• 2020

The purpose of this study is to propose the possibility of precise surface sedimentary facies classification and a more accurate classification method by generating the large-scale map of surface sedimentary facies based on UAV data and object-based image analysis (OBIA) for Hwang-do tidal flat in Cheonsu bay. The very high resolution UAV data extracted factors that affect the classification of surface sedimentary facies, such as RGB ortho imagery, Digital elevation model (DEM), and tidal channel density, and analyzed the principal components of surface sedimentary facies through statistical analysis methods. Based on principal components, input data to be used for classification of surface sedimentary facies were divided into three cases such as (1) visible band spectrum, (2) topographical elevation and tidal channel density, (3) visible band spectrum and topographical elevation, tidal channel density. The object-based image analysis classification method was applied to map the classification of surface sedimentary facies according to conditions of input data. The surface sedimentary facies could be classified into a total of six sedimentary facies following the folk classification criteria. In addition, the use of visible band spectrum, topographical elevation, and tidal channel density enabled the most effective classification of surface sedimentary facies with a total accuracy of 63.04% and the Kappa coefficient of 0.54.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.25-39
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• 2010

Recently, GIS softwares such as WMS, ArcHydro, and HyGIS which can calculate hydrological geographic parameters are popularized. These softwares have the functions to calculate various geographic parameters which are used in water resources from DEM (Digital Elevation Model). In this study, hydrological geographic parameters calculated by WMS and ArcHydro are compared and examined with them from HyGIS to evaluate the applicability of the parameters from HyGIS. Bochungcheon (Riv.), Wicheon (Riv.), Pyungchanggang (Riv.), Gyungancheon (Riv.), Naerincheon (Riv.), and Imjingang (Riv.) watersheds are selected for this study, and the shape of watershed, watershed area, watershed slope, the average slope of watershed, main stream length, main stream slope, maximum flow distance, and the slope of maximum flow distance are calculated to compare and examine the characteristics. Study results show that the average relative error of 7 geographic parameters from all the watersheds is 4.77 %, and all the watershed boundaries are very similar. So, all the geographic parameters calculated by each software show very similar value, and the geographic parameters calculated by HyGIS can be applied to water resources with WMS and ArcHydro which have been generally used.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.195-206
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• 2014

In this study, soil contamination maps related to Cu and Pb were created at the Busan abandoned mine in Korea using a handheld X-Ray Fluorescence(XRF) and Geographic Information Systems(GIS). Hydrological analysis was performed using the Digital Elevation Model(DEM) of the study area to identify the flow directions of surface runoff where pollutants can be dispersed from the soil contamination sources. 24 locations for measuring the soil contamination related to Cu and Pb were selected by considering the result of hydrological analysis. The results measured at the 24 locations using the handheld XRF showed that the highest value of Cu contamination is 8,255ppm and that of Pb is 2,146ppm. The field investigation data were entered into ArcGIS software, and then soil contamination maps regarding Cu and Pb with a 5m grid-spacing were created after performing spatial interpolations using the ordinary kriging method. As a result, we could know that high concentrations of Cu and Pb are presented at the waste and tailings dumps around the abandoned mine openings. This study also showed that the handheld XRF and GIS can be utilized to create soil contamination maps related to Cu and Pb in the field.