• Title/Summary/Keyword: Topographic Information

Search Result 608, Processing Time 0.021 seconds

Estimation of Solar Energy Based on High-Resolution Digital Elevation Model on the Seoul Area (서울지역의 고해상도 수치표고모델기반 태양 에너지 산출)

  • Jee, Joon-Bum;Jang, Min;Min, Jae-Sik;Zo, Il-Sung;Kim, Bu-Yo;Lee, Kyu-Tae
    • Atmosphere
    • /
    • v.27 no.3
    • /
    • pp.331-344
    • /
    • 2017
  • Solar energy is calculated using high-resolution digital elevation model (DEM). In focus on Seoul metropolitan area, correction coefficients of direct and diffuse solar energy with the topographic effect are calculated from DEM with 1720, 900, 450, 90 and 30 spatial resolutions ($m{\times}m$), respectively. The solar energy on the real surface with high-resolution is corrected using by the correction coefficients with topographic effect from the solar energy on horizontal surface with lower resolution. Consequently, the solar energy on the real surface is more detailed distribution than those of horizontal surface. In particular, the topographic effect in the winter is larger than summer because of larger solar zenith angle in winter. In Seoul metropolitan area, the monthly mean topographic effects are more than 200% in winter and within 40% in summer. And annual topographic effects are negative role with more than -60% and positive role with below 40%, respectively. As a result, topographic effect on real surface is not a negligible factor when calculating and analyzing solar energy using regional and global models.

Estimation of the Topographic Factor of Wind Speed Using GIS Information (GIS 정보를 이용한 풍속지형계수 산정)

  • Seong, Min-Ho;Choi, Se-Hyu
    • Spatial Information Research
    • /
    • v.19 no.5
    • /
    • pp.47-52
    • /
    • 2011
  • Recently damage scale by local winds and typhoon has dramatically increased. Korea has the terrain over 70% of the land and the planning of the wind load is necessary to estimate reflecting appropriately the change of the wind-speed according to the characteristic of the terrain and in the Korean Building Code(2009), this is stated and it reflects to the design process. However, in order to estimate the topographic factor of the wind speed considering the topographic characteristics in the structure design actually, it has many difficult points including the local topographic survey, etc. In this paper, the Digital Elevation Model(DEM) is created using TIN interpolation method in the form of the digital map and then the interface was designed and implemented which can automatically estimate the topographic factor of wind speed by using ESRI(R)ArcObjectTM and the Visual Basic programing language. By applying it to the terrain which positioned in the downtown area, the practicality of the topographic factor of wind speed estimation interface was checked.

APPLICATION OF LOGISTIC REGRESSION MODEL AND ITS VALIDATION FOR LANDSLIDE SUSCEPTIBILITY MAPPING USING GIS AND REMOTE SENSING DATA AT PENANG, MALAYSIA

  • LEE SARO
    • Proceedings of the KSRS Conference
    • /
    • 2004.10a
    • /
    • pp.310-313
    • /
    • 2004
  • The aim of this study is to evaluate the hazard of landslides at Penang, Malaysia, using a Geographic Information System (GIS) and remote sensing. Landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys. Topographical and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. The factors chosen that influence landslide occurrence were: topographic slope, topographic aspect, topographic curvature and distance from drainage, all from the topographic database; lithology and distance from lineament, taken from the geologic database; land use from TM satellite images; and the vegetation index value from SPOT satellite images. Landslide hazardous area were analysed and mapped using the landslide-occurrence factors by logistic regression model. The results of the analysis were verified using the landslide location data and compared with probabilistic model. The validation results showed that the logistic regression model is better prediction accuracy than probabilistic model.

  • PDF

Calculation of Topographic Index with Geographic Information System

  • Kim, Sang-Hyun;Ham, Kun-Yeun
    • Korean Journal of Hydrosciences
    • /
    • v.8
    • /
    • pp.85-95
    • /
    • 1997
  • The multiple flow direction algorithm to calculate the spatial variation of the saturation tendency, I. e. topographic index, is integrated into the Geographic Information System, GRASS. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed ($3.4\;\textrm{km}^2$) is used for this study. The impact of a tile system on the groundwater table can be effectively considered by the Laplace's equation to the DEM. The analysis shows that a tile system has a high degree of saturation to compared to the case without tile drainage, and the predicted riparian area is well fitted to the actual watershed condition. A procedure is suggested to consider a tile system's effect on calculating the topographic index.

  • PDF

Production of Topographic-Cadastral Map Using Digital Topographic Map (수치지형도를 활용한 지형.지번도 제작방안)

  • 최윤수;이석용
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.18 no.3
    • /
    • pp.241-250
    • /
    • 2000
  • The Government confirmed the action planning of digital mapping project for major thematic maps based on‘Revised Plan for The Development of the National Geographic Information System’(NGIS). Mapping for major thematic maps will selectively have produced the essential digital thematic maps according to the frequency of usage by the year of 2000. The models of topographic-cadastral maps around Suwon were produced in accordance with the presented draft. We presented specification for production of the most appropriate topographic-cadastral maps through the analysis of the process of production, discussion and error check, and correction of the produced topographic-cadastral maps. And we could make it easier to develop digital mapping project of topographic-cadastral maps effectively by presenting the strategy for data input and maintenance, the cost model for carrying out the digital thematic map production, digital topographic maps, and the supplement of data model and data format.

  • PDF

A method for Measuring Positional Accuracy of Road Objects in Digital Topographic Maps (수치지도 도로사상의 위치정확도 측정방법)

  • 박수홍;구자용
    • Spatial Information Research
    • /
    • v.7 no.1
    • /
    • pp.119-131
    • /
    • 1999
  • Various digital topographic maps including 1:1,000 and 1:5,000 have been produced for years and these digital maps are expected to serve a wide range of purposes. Most previous research about measuring positional accuracy for digital topographic maps depends int a method that acquires sample points from the tested map and compares to the corresponding known true locations using some statistics. Recently, a simple method for measuring positional accuracy for linear features is introduced but it has substantial problems applying to the spatial features such as roads, railroads, streams represented with double lines on the recently produced 1:1,000 and 1:5,000 digital topographic maps. This study develops and implements an effective method that measures road objects represented in the 1:5,000 digital topographic maps using a conventional GIS software. We also apply this method to a small study area located in Kangnam Gu, Seoul and illustrate the usefulness of this method.

  • PDF

Establishment of Quality Checking Factors for Construction Process of Digital Topographic Map (수치지형도 제작과정의 품질관리요소 정립에 관한 연구)

  • Choi, Byoung-Gil;Kim, Kam-Lae;Moon, Yong-Hyun
    • 한국지형공간정보학회:학술대회논문집
    • /
    • 2005.08a
    • /
    • pp.73-83
    • /
    • 2005
  • This study aims to establish the quality checking factors for the construction process of digital topographic map. Total 17 regulations related to quality of digital topographic map and major aerial survey firms are analyzed in terms of working process, equipments, and accuracy of results. It is standardized the process of making new digital maps using aerial photography, revising existing digital maps, and digitizing paper map. Quality checking factors for the construction process of digital topographic map are also established.

  • PDF

Accuracy Analysis of Ortho Imagery with Different Topographic Characteristic (지역적 특성에 따른 정사영상의 정확도 분석)

  • Jo, Hyun-Wook;Park, Joon-Kyu
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.11 no.1
    • /
    • pp.80-89
    • /
    • 2008
  • Mapping applications using satellite imagery have been possible to quantitative analysis since SPOT satellite with stereo image was launched. Especially, high resolution satellite imagery was efficiently used in the field of digital mapping for the areas which are difficult to produce large-scale maps by aerial photogrammetry or carry out ground control point surveying due to unaccessibility. This study extracted the geospatial information out of consideration for topographic characteristic from ortho imagery of the National Geospatial-intelligence Agency(NGA) in the United States of America and analyzed the accuracy of plane coordinate for ortho imagery. For this purpose, the accuracy according to topographic character by comparison between both extraction data from ortho imagery and the digital topographic maps of 1:5000 scale which were produced by Korea National Geographic Information Institute(NGI) was evaluated. It is expected that the results of this study will be fully used as basic information for ground control point acquisition or digital mapping in unaccessible area.

  • PDF

Development of the Visualization Prototype of Radar Rainfall Data Using the Unity 3D Engine (Unity 3D 엔진을 활용한 강우레이더 자료 시각화 프로토타입 개발)

  • CHOI, Hyeoung-Wook;KANG, Soo-Myung;KIM, Kyung-Jun;KIM, Dong-Young;CHOUNG, Yun-Jae
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.18 no.4
    • /
    • pp.131-144
    • /
    • 2015
  • This research proposes a prototype for visualizing radar rainfall data using the unity 3D engine. The mashup of radar data with topographic information is necessary for the 3D visualization of the radar data with high quality. However, the mashup of a huge amount of radar data and topographic data causes the overload of data processing and low quality of the visualization results. This research utilized the Unitiy 3D engine, a widely used engine in the game industry, for visualizing the 3D topographic data such as the satellite imagery/the DEM(Digital Elevation Model) and radar rainfall data. The satellite image segmentation technique and the image texture layer mashup technique are employed to construct the 3D visualization system prototype based on the topographic information. The developed protype will be applied to the disaster-prevention works by providing the radar rainfall data with the 3D visualization based on the topographic information.

Estimation of channel morphology using RGB orthomosaic images from drone - focusing on the Naesung stream - (드론 RGB 정사영상 기반 하도 지형 공간 추정 방법 - 내성천 중심으로 -)

  • Woo-Chul, KANG;Kyng-Su, LEE;Eun-Kyung, JANG
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.25 no.4
    • /
    • pp.136-150
    • /
    • 2022
  • In this study, a comparative review was conducted on how to use RGB images to obtain river topographic information, which is one of the most essential data for eco-friendly river management and flood level analysis. In terms of the topographic information of river zone, to obtain the topographic information of flow section is one of the difficult topic, therefore, this study focused on estimating the river topographic information of flow section through RGB images. For this study, the river topography surveying was directly conducted using ADCP and RTK-GPS, and at the same time, and orthomosiac image were created using high-resolution images obtained by drone photography. And then, the existing developed regression equations were applied to the result of channel topography surveying by ADCP and the band values of the RGB images, and the channel bathymetry in the study area was estimated using the regression equation that showed the best predictability. In addition, CCHE2D flow modeling was simulated to perform comparative verification of the topographical informations. The modeling result with the image-based topographical information provided better water depth and current velocity simulation results, when it compared to the directly measured topographical information for which measurement of the sub-section was not performed. It is concluded that river topographic information could be obtained from RGB images, and if additional research was conducted, it could be used as a method of obtaining efficient river topographic information for river management.