• Journal of Environmental Science International
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• v.33 no.7
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• pp.443-452
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• 2024

The recent increase in impermeable surfaces due to urbanization and the occurrence of concentrated heavy rainfall events caused by climate change have led to an increase in urban flooding. To predict and prepare for flood damage, a convenient and highly accurate simulation of rainfall-runoff based on geospatial information is essential. In this study, the storm water management model (SWMM) was applied to simulate rainfall runoff in the Bangbae-dong area of Seoul, using two sets of topographical data: The conventional topographic digital elevation model (TOPO-DEM) and the proposed shuttle radar topography mission (SRTM)-DEM. To evaluate the applicability of the SRTM-DEM for rainfall-runoff modeling, two DEMs were constructed for the study area, and rainfall-runoff simulations were performed. The construction of the terrain data for the study area generally reflected the topographical characteristics of the area. Quantitative evaluation of the rainfall-runoff simulation results indicated that the outcomes were similar to those obtained using the existing TOPO-DEM. Based on the results of this study, we propose the use of SRTM-DEM, a more convenient terrain data, in rainfall-runoff studies, rather than asserting the superiority of a specific geospatial data.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.799-810
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• 2003

Hydrologic models generally require land surface analysis to different topographic parameters defined as direct or indirect input variables to the model. Specially GIS supply the these parameters from digital data set of land surface The sensitivity analysis to DEM(Digital Elevation Model) resolution and the threshold area are of GIS extracted digital data set applied GIUH(Geomorphological Instantaneous Unit Hydrograph)model is investigated. Also it is compared the responses of GIUH model as input data of stream networks from digital data set(blue line) of NGIS and those extracted from DEM of various grid sizes. The results shows that the GIUH model is significantly affected by the DEM resolution and threshold area. According to the results, DEM grid size is suitable from 25m to 50m. Also threshold area is in the range of 30%∼50% for exceedance probability.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.3
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• pp.19-32
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• 2002

Topographic information is indispensable in the applications that require elevational data. These applications are exemplified by watershed partition, extraction of drainage networks, viewshed analysis, derivation of geomorphologic features, quantification of landslide-terrain, and identification of topographic settings susceptible to landsliding. Therefore, we study the accuracy of data on topographic parameters derived from digital elevation models(DEMs). This research wished to analyze the effect that data source and grid size get in topography parameter using gridded DEM. An analysis of topography parameter extract and compared drainage basin, watershed slope, stream network using DEM is constructed by digital map and DTED DEM. Especially, when extract stream network from gridded DEM, received much effects according to threshold value of flowaccumulation regardless of DEM grid size. Therefore, this study applied equal threshold value of flowaccumulation for two data sources, and compare and analyzed stream network.

• Korean Journal of Remote Sensing
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• v.35 no.5_1
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• pp.693-703
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• 2019

Long-term coastal topographical data is critical for analyzing temporal and spatial changes in shorelines. Especially understanding the change trends is essential for future coastal management. For this research, in the data preparation, we obtained digital aerial images, terrestrial laser scanning data and UAV images in the year of 2009. 2018 and 2019 respectively. Also tidal observation data obtained by the Korea Hydrographic and Oceanographic Agency were used for Bangamoeri beach located in Ansan, Gyeonggi-do. In the process of it, we applied the photogrammetric technique to extract the coastline of 4.40 m from the stereo images of 2009 by stereoscopic viewing. In 2018, digital elevation model was generated by using the raw data obtained from the laser scanner and the corresponding shoreline was semi-automatically extracted. In 2019, a digital elevation model was generated from the drone images to extract the coastline. Finally the change rate of shorelines was calculated using Digital Shoreline Analysis System. Also qualitative analysis was presented.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.361-372
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• 2016

The purpose of this study was to examine the mediating effect of moral elevation and self control on the relationship between moral identity, character strengths, family strengths, and altruistic behavior in the times of convergence. The collected data were analyzed by SEM. The results of this study were as follows: First, moral self has indirect effect on altruistic behavior through moral elevation and self control in turn, and character strengths, have indirect effect on altruistic behavior through moral elevation and self control and moral elevation, self control in turn, and family strengths have indirect effect on altruistic behavior through self control. Second, it was found that there was a significant gender difference in the structural weights of character strengths and moral elevation.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.33-42
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• 2003

As airborne laser scanning technique is developed with high vertical accuracy recently, there come many studies on DEM(digital elevation model creation, building extraction, flood risk mapping and 3D virtual city modeling. This study applied point comparative method, contour comparative method and digital map with scale 1/5,000 to calculate RMSE of DEM in according to resolution that was constructed using rawdata being acquired by airborne laser scanning. As a result, point comparative method showed lower DEM standard error than contour comparative method, it is a reason that contour comparative method was not carried out detailed grid calculation for point comparative method. Also, digital map with scale 1/5,000 showed higher DEM standard error than point comparative method and contour comparative method in below 25.4m that is average horizontal distance among contour line, and showed similar result with contour comparative method in over 25.4m.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.319-326
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• 2006

All around tile world there has been great human and economical damage continuously by disasters like the earthquakes and storms(Tsunami) in eastern asia which recently occurred, and like the New Orleams hurricane in USA. The situation is our countries damage from natural disasters due to heavy snow, storms, forest fires have been increasing In this research we obtained GSIS data of the 05' Yang-yang forest fire disaster area using multi-sensors like airborne laser data, GPS/INS, aerial photograph surveying. In result we produced digital topographical maps, digital elevation models, digital external models, digital images, infrared images. By, analyzing and comparing with past aerial photography we obtained the exact damage area, amount of damage, estimated tile areas where a landslide might occur, and we analyzed vegetations amount of damage and possibility of recovery.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.685-693
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• 2015

We propose a method for deriving the relationship between channel width and discharge from remote sensing products. Stream widths at points distributed along a river network can be measured from high-resolution remote imagery. Further, corresponding drainage area for these points can be calculated using digital elevation models, making it possible to construct width-drainage area relation. On the other hand, the relationship between the flow discharge and the drainage area is obtained from historical data measured at ground stations. By coupling these two relationships, we can finally derive the width-discharge relationship which comprises an important component of downstream hydraulic geometry. The proposed method was tested for the Nakdong River and the Seomjin River, successfully capturing power-law exponents in the width-discharge relationships reported in earlier studies. The proposed approach can serve as an alternative for obtaining the hydraulic geometry relationship under the limits of ground data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.263-266
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• 2004

We make DEM of the area that elevation value varies rapidly by the aid. This study evaluates the accuracy and workability between the existing DEM making mathod by processing break line and the DEM absorption method by using the program like ARC TIN or AML. The object data of DEM generation is 1/5,000 digital map publicated by NGII and this study uses 100pieces of map as the criteria. We correct the error by Geoconv and generate DEM by using ARC TIN, ARC VIEW. Accuracy Evaluation accomplished by drawing 100 points from 1/5000 digital map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.61-67
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• 1999

A watershed terrain factor is known to the very important in studies of a stream and a watershed. We have obtained the terrain factor in map directly or we have generated it in a digitalized map. In this study, DTED (Digital Terrain Elevation Data) offering in DMA(Defense Mapping Agency) was used to create a stream and a watershed and to extract the terrain factor. As comparison of the terrain factors gererated in digitalized map with the terrain factors extracted in DTED, DTED could be used to extract a terrain factor for a watershed management.