• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4_1
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• pp.97-106
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• 1992

Total length of stream networks and main stream length vary with topographic map scales, and the stream length of drainage basin on topographic map can be viewed as a fractal. Total length of stream network and main stream length are represented as only stream area ratio($R_a$) based on Horton's laws, thereafter the fractal dimensions of stream network and main stream length are derived as a simple function of stream length($R_L$) and stream area ratios($R_a$) respectively. The derived equations of fractal dimension are applied to Sansung basin in Kum River and compared with the equations already existed. The stream network appeared as space filling with fractal dimension near 2 as map scale increases, while main stream length shows near 1. The results of this study are expected to be helpful in the quantitative analysis of drainage network composition with map scale.

• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.379-390
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• 2005

This study is to trace the change of stream shape using the past series of aortal photographs and topographic maps, and to compare the land use changes of inland along the stream. For the Gyeongan first & second class of local stream, aerial photographs of 1966, 1981 and 2000 were selected and ortho photographs were made with interior orientation and exterior orientation, respectively. In addition, topographic maps of 1914 - 1915 were used to compare with stream of 1966, 1981 and 2000. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream width widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974. The land use maps (1966, 1981, 2000) of riparian areas were also made, respectively and classified into 6 categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing, The main changes of land use were agricultural land, urban area, road and sandbar.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.1 s.35
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• pp.49-55
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• 2006

Nowadays, flood hazard maps have been generated to minimize the damages from the flooding. To generate such flood hazard maps, LiDAR data can be used as data source with higher data accuracy. LiDAR data, however, requires relatively higher cost and longer processing time. In this background, this study proposed DEM generation using NGIS digital topographic maps. For that, breaklines were processed to count directions of water flows. In addition, the river profile data, unique data source to represent real topography of the river area, were integrated to the breaklines to generate DEM. City of Kuri in Kyunggi Province was selected for this study and 1:1,000 and 1:5,000 topographic maps were integrated to process breaklines and river profile data were also linked to generate DEM. The generated DEM showed relatively lower vertical accuracy from mixing 1:1,000 and 1:5,000 topographic maps since 1:1,000 topographic maps were not available for some portion of the area. However, the DEM generated demonstrated reasonable accuracy and resolution for flood map generation as well as higher cost saving effects. On the contrary, for more efficient utilization of NGIS topographic maps, periodic map updating needs to be made including technical consideration in building breaklines and applying interpolation methods.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.411-415
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• 2011

홍수 및 침수 등의 재해로부터 사전예방 및 신속한 대응을 위한 기초자료로서 홍수위험지도 및 재해지도는 반드시 필요하고, 이러한 위험지도 제작에 있어 가장 핵심적인 내용은 시나리오별 홍수범람해석이다. 현재 우리나라는 국가하천 규모 및 지방하천 중 침수피해가 큰 구간에 대해 제한적 범위내에 2차원 해석을 적용하여 위험지도 제작을 하고 있지만 지방하천 및 소하천의 경우 각종 기본계획 및 종합계획에서 일부 1차원 수리 해석 후 GIS와 연계를 통해 홍수범람해석이 이루어지거나 대부분 수치지도의 등고선과 홍수위를 이용하여 수작업으로 범람구역을 표기하고 있는 실정이다. 따라서 본 연구는 홍수범람해석시 수작업의 동반으로 인한 가장 많은 시간과 인력적 비용이 요구되고 GIS의 고급기능 등을 반드시 숙지해야하므로 인해 범람해석의 걸림돌이었던 하천지형 구축부분에 대해 기존의 방법인 1:5,000 수치지형도부터 DEM 생성 및 적용과 WMS를 통해 전 세계 수치지형을 신속하고 편리하면서 무료로 제공받을 수 있는 ASTE과, SRTM DEM을 각각 적용하여 각각의 하천지형을 구축하여 HEC-RAS 및 HEC-GeoRAS를 이용하여 수리해석 및 범람해석을 수행하였으며 그 결과를 비교 분석하였다. 본 연구의 결과는 WMS에서 제공되는 Online DEM을 적용하여 신속하고 편리하게 하천지형을 구축함으로서 시간 및 인력적 비용을 절감하고 비교적 적절한 홍수범람해석 결과를 얻을 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.312-312
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• 2022

우리나라는 하천법 및 소하천정비법에 의거하여 하천기본계획 수립 또는 하천의 지정 및 변경고시 시 하천구역을 지정하고 있다. 하천구역은 일반적으로 제방부지 및 제방하심측 토지경계를 기준으로 지정하나, 제방이 존재하지 않는 무제부 구간의 경우 명확한 제방경계가 없는관계로 하천법 제 10조 3항에서 5항까지 별도의 기준을 통해 하천구역 지정을 권장하고 있는 실정이다. 하천구역 설정 시 기준으로 삼는 횡단측점 자료의 경우 그 특성상 하천의 종단방향으로 불연속적인 특징을 갖고 있어 평면상 정확한 경계의 파악이 어려우며, 도로·철도 등 선형시설경계를 하천구역으로 설정 시 편입용지의 보상기준이 모호하여 다량의 민원이 발생하고 있다. 본 연구에서는 하천정비 시 기본계획이 수립되어 각 횡단측점별 결정된 계획홍수위를 기반으로 인접 지형의 홍수위 영향범위를 자동으로 추출하여 하천구역을 정밀하게 결정할 수 있는 방법론을 정립하고자 한다. 첫째로, 하천중심선의 각 측점의 위치정보와 하천의 지형을 위상정보체계로 구성하여 DB를 구축하였다. 둘째로, 측선과 측선사이 절점에 계획홍수위를 선형보간하여 부여하고 이를 지형도의 최단거리에 위치한 지형의 격자표고와 비교해 침수여부를 판단한다. 셋째, 최단거리 지형격자가 침수로 판단될 시 인접한 8개 지형격자의 지형표고와 홍수위를 비교하여 반복적으로 위 과정 수행을 통해 계획홍수위 기반 침수범위를 추출한다. 마지막으로, 이를 수치지형도에 중첩시켜 최종 정밀 하천구역을 결정할 수 있다. 이를 이용하여 산정된 정밀한 하천구역 경계설정을 통해 하천 내사유지 편입을 최소화함과 동시에 명확한 하천구역 구획기준을 정립하여 토지소유주와 담당부처 간 논의 시 기반자료로 활용될 수 있고, 하천구역의 신속하고 정확한 구역설정을 통해 하천인근의 토지이용 고도화 및 효율적인 이용이 가능할 것으로 기대된다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.11a
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• pp.50-53
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• 2004

하천 분기특성을 이용한 유출해석모형에서 최소하천의 크기는 매우 민감한 영향을 미치게 되므로 본 연구에서는 금호강 중류의 금호수위표지점 상류 유역을 대상으로 하여 DEM 격자크기와 최소차 하천의 임계면적에 따른 지형매개변수의 변화특성을 검토하였다. 분석에서는 유역내의 1:25,000 수치지형도를 $10\times10,\;30\times30,\;50\times50m$ 격자망으로 구성하여 하천차수별 개수, 유로연장, 면적, 만곡도, 배수밀도 및 유로연장 등을 대상으로 하였다.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.135-144
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• 2017

The riverbed areas have exposed to various natural disasters and the private use by neighboring residents have caused many problems. The research objectives are to survey the actual situation of riverbed areas in order to prevent landscape damage and private use. Drone and photogrammetry, orthophoto, DSM(Digital Surface Model), digital topographic map and cadastral information have been integrated by GIS technology. The flood and disaster vulnerable area has been surveyed and the land use and private use has been analyzed using cadastral information. The research results show that the analyzed data can be used for providing foundation data for management of river and also can be used for surveying actual situation of private use on the riverbed areas.

• 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.

• Journal of Korea Water Resources Association
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• v.32 no.3
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• pp.291-300
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• 1999

The Snyder's synthetic unit hydrograph method is selected to apply the concept of the fractal dimension by stream order for the practicable rainfall-runoff generation, and fourth types of the Snyder's relation are derived from topographic and observed unit hydrograph data of twenty-nine basins. As a result of the analysis of twenty-nine basins and the verification of two basins, the Snyder's relation which considers the fractal dimension of the stream length and uses calculated unit hydrograph data shows the best result. The concept of the fractal dimension by stream order is applied to the Snyder's synthetic unit hydrograph method. The topographic factors, used in the Snyder's synthetic unit hydrograph method, which have a property of the stream length like $L_{ma}$ (mainstream length) and $L_{ca}$ (length along the mainstream to a point nearest the watershed centroid) were considered. In order to simplify the fractal property of stream length, it is supposed that $L_{ma}$ has not the fractal dimension and the stream length between $L_{ma}$ and ($L_{ma}\;-\;L_{ca}$) has the fractal dimension of 1.027. From the utilization of this supposition, a new Snyder's relation which consider the fractal dimension of the stream length occurred by the map scale used was finally suggested.

• Journal of Korea Water Resources Association
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• v.52 no.8
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• pp.515-529
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• 2019

Geospatial information for river network and watershed boundary have played a fundamental roles in terms of river management, planning and design, hydrological and hydraulic analysis. Irrespective of their importance, the lack of punctual update and improper maintenance in currently available river-related geospatial information systems has revealed inconsistency issues between individual systems and spatial inaccuracy with regard to reflecting dynamically transferring riverine geography. Given that digital elevation models (DEMs) of high spatial resolution enabling to reproduce precise river network are only available adjacent to national rivers, DEMs with poor spatial resolution lead to generate unreliable river network information and thereby reduce their extensible applicabilities. This study first of all evaluated published spatial information available in Korea with respect to their spatial accuracy and consistency, and also provides a methodology and tool to modify existing low resolution of DEMs by means of striation of conventional or digitized river network to replicate input river network in various degree of further delineation. The tool named FSND was designed to be operated in ArcGIS ModelBuilder which ensures to automatically simulate river network striation to DEMs and delineation with different flow accumulation threshold. The FNSD was successfully validated in Seom River basin to identify its replication of given river network manually digitized based on recent aerial photograph in conjunction with a DEM with 30 meter spatial resolution. With the derived accuracy of reproducibility, substantiation of a various order of river network and watershed boundary from the striated DEM posed tangible possibility for highly extending DEMs with low resolution to be capable of producing reliable riverine spatial information subsequently.