• Title/Summary/Keyword: Terrain data

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A 3-D Visualization Method for Geographical Information based on Contour Lines (등고선을 이용한 자행정보의 3차원 시각화 기법)

  • Han, Jung-Kyu;Baek, Joong-Hwan;Hwang, Soo-Chan
    • Journal of Advanced Navigation Technology
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    • v.5 no.2
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    • pp.123-133
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    • 2001
  • The existing visualization methods using the satellite images or map images require complicated preprocessing stages and a large amount of visual data to represent the 3-D terrain. This paper presents a 3-D visualization method for geographical information, which enables automatic generation of 3-D terrain. It is generated based, on contour information obtained from a numerical map. This paper also introduces a method that resolves the three main problems needed to visualize 3-D terrain from contour lines such as correspondence, tiling, and branching. The virtual contour line is defined to extend a distorted contour line to have a similar shape to the corresponding contour line that is used, to generate 3-D surfaces. It helps that 3-D terrain is represented exactly and in detail.

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Object Detection From 3D Terrain Data Gener Ated by Laser Scanner of Intelligent Excavating System(IES) (굴삭 자동화를 위한 레이저 스캐너 기반의 3차원 객체 탐지 알고리즘의 개발)

  • Yoo, Hyun-Seok;Park, Ji-Woon;Choi, Youn-Nyung;Kim, Young-Suk
    • Korean Journal of Construction Engineering and Management
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    • v.12 no.6
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    • pp.130-141
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    • 2011
  • The intelligent excavating system(IES), the development in South Korea of which has been underway since 2006, aims for the full-scale automation of the excavation process that includes a series of tasks such as movement, excavation and loading. The core elements to ensure the quality and safety of the automated excavation equipment include 3D modeling of terrain that surrounds the excavating robot and the technology for detecting objects accurately(i.e., for detecting the location of nearby loading trucks and humans as well as of obstacles positioned on the movement paths). Therefore the purpose of this research is to ensure the quality and safety of automated excavation detecting the objects surrounding the excavating robot via a 3D laser scanning system. In this paper, an algorithm for estimating the location, height, width, and shape of objects in the 3D-realized terrain that surrounds the location of the excavator was proposed. The performance of the algorithm was verified via tests in an actual earthwork field.

GPU-based Adaptive LOD control for Quadtree-Based Terrain Rendering (사진트리 기반 지형렌더링을 위한 GPU기반의 적응형 상세단계 조정 방법)

  • Choi, In-Ji;Shin, Byeong-Seok
    • Journal of Korea Game Society
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    • v.8 no.3
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    • pp.61-68
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    • 2008
  • Quadtree-based terrain visualization methods have been used in a lot of applications. However, because most procedures are performed on the CPU, the rendering speed is slow in comparison to methods using GPU. In this paper, we present a quadtree-based terrain visualization method working on the GPU with specially designed data structure, error-texture and LOD-texture, and block-based acceleration method. In preprocessing step, we calculate errors in world space and store them to error-texture. In rendering step, we examine projected errors of error-texture and choose the detail level, then store the projected errors to LOD-texture. View frustum culling is performed as block unit using the values of error-texture and LOD-texture. This method reduces CPU load and performs time consuming jobs such as LOD selection and view frustum culling.

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A Study on the Terrain Analysis using TIN & GRID-Based Digital Terrain Model (TIN과 GRID기반의 수치지형모델을 이용한 지형분석에 관한 연구)

  • 윤철규
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.16 no.1
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    • pp.67-74
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    • 1998
  • This paper performed terrain analysis using DTM(digital terrain model) with TIN/ GRID structure on PC environment. Contour layer from 1:5,000 scale map was used to produce DTM. DTHs were produced with and without considering breakline for each data structure. Processing time, file size, mean elevation and standard variation were analyzed for each DTM. slope map, aspect map were analyzed for grid structure with consideration of TEX>$5\times{5m},\;l0\times{10m},\;15\times{15m},\;l0\times{30m},\;45\times{45m},\;60\times{60m}$ cell size respectively. The results suggest following; The incorporation of breakline does improve mapping accuracy for highly disturbed landscape, Mean elevation doesn't increase as the grid size increases, while processing time, storage room is significantly lessened. Thus, the optimal grid size must be determined in advance for efficient application. slope decreases, while aspect increases as grid size is increasing.

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A performance analysis of terrain-aided navigation(TAN) algorithms using interferometric radar altimeter (간섭계 레이더 고도계를 활용한 지형참조항법의 성능 분석)

  • Jeong, Seung-Hwan;Yoon, Ju-Hong;Park, Min-Gyu;Kim, Dae-Young;Sung, Chang-Ki;Kim, Hyun-Suk;Kim, Yoon-Hyung;Kwak, Hee-Jun;Sun, Woong;Yoon, Kuk-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.4
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    • pp.285-291
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    • 2012
  • The paper experimentally verifies the performance of Terrain-Aided Navigation (TAN) using an interferometric radio altimeter, which is recently used due to its accuracy. First, we propose a TAN system that utilizes an interferometric radio altimeter as a measurement system. Second, we implement extended Kalman filter, unscented Kalman filter, and particle filter to evaluate the performance of TAN according to the selection of filters and the difference of environments.

Analysis of UAV Photogrammetric Method for Generation of Terrain Model and Ortho Image (지형모델 및 정사영상 제작을 위한 무인항공측량 기술 분석)

  • Um, Dae Yong;Park, Joon Kyu
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.6 no.8
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    • pp.577-584
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    • 2016
  • UAV(Unmaned Aerial Vehicle), which is autonomous flight without pilots. Recently, UAV is being applied to various fields such as video recording, aerial photogrammetry. In particular, UAV is getting a lot of attention in the field of space-related information because of it's data acquisition speed and economic feasibility. But analytical study of an unmanned air-side technologies are lacking. In this study, the research of equipment for the unmanned aerial surveys and UAV technologies and trend analysis for generation of terrain model and ortho image effectively were performed. As a result, the ways to improve the utilization field of unmanned aerial surveying and processing of fixed-wing and rotary-wing unmanned aircraft. were suggested. If analytical research on generation of terrain models and ortho image will be performed, production efficiency of the geospatial information industry is expected to be significantly increased.

Movement Analyzing of Soil Moisture at a Hillslope Scale Considering Spatial-Temporal and Seasonal Characteristics (시공간적, 계절적 특성을 고려한 사면에서의 토양수분의 거동파악)

  • Oh, Kyung-Jun;Kwak, Yong-Seok;Do, Hoon-Kim;Kim, Sang-Hyun;Kim, Hyun-Jun;Kim, Nam-Won
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.678-682
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    • 2006
  • In order to analyze movement of soil moisture, Time Domain Reflectometry(TDR) with multiplex system has been installed at the Bumreunsa hillslope of Sulmachun Watershed to configure spatial-temporal variation pattern considering seasonal characteristic. An intensive surveying was performed to build a refined digital elevation model(DEM) and flow determination algorithms with inverse surveying have been applied to establish an efficient soil moisture monitoring system. Soil moisture data were collected through an intensive and long term monitoring 380 hrs in November of 2003 and 1037 hrs in May and June of 2004. Soil moisture data shows corresponding variation characteristics of soil moisture on the up slope, buffer, main channel zones of the hillslope which were classified from terrain analysis. Inferences and limitations of measured soil moisture data were discussed in conjunction with flow characteristic through terrain analysis.

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A STUDY ON THE MOHO UNDULATION OF THE KOREAN PENINSULA FROM SATELLITE GRAVITY DATA

  • Yu, Sang-Hoon;Hwang, Jong-Sun;Min, Kyung-Duck
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.589-592
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    • 2005
  • Gravity characteristics and Moho undulations are investigated in the Korean peninsula by using satellite gravity data. According to the development of satellite geodesy, gravity potential models which have high accuracy and resolution were released. Using the EIGEN-CGOIC model based on low orbit satellite data such as CHAMP and GRACE, geoid and gravity anomaly were calculated by spherical harmonic analysis. The study area is located at $123^{\circ}\sim132^{\circ}E, 33^{\circ}\sim43^{\circ}$N including Korea. Free-air anomalies, which show the effect of terrain, have the values between $-37\sim724 mgal. After Bouguer correction, the range of simple Bouguer anomalies is $-221\sim246$ mgal. Complete Bouguer anomalies after terrain correction increase from continent to marine. This phenomenon is related rise of Moho discontinuity. The cut-frequency for extraction of Moho undulation was determined by power spectrum analysis, and then 3D inversion modeling was implemented. The mean, maximum, minimum, and standard deviation of Moho depth undulation are -26, -36, -8, and 4.9 krn, respectively.

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Point Cloud Data Driven Level of detail Generation in Low Level GPU Devices (Low Level GPU에서 Point Cloud를 이용한 Level of detail 생성에 대한 연구)

  • Kam, JungWon;Gu, BonWoo;Jin, KyoHong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.6
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    • pp.542-553
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    • 2020
  • Virtual world and simulation need large scale map rendering. However, rendering too many vertices is a computationally complex and time-consuming process. Some game development companies have developed 3D LOD objects for high-speed rendering based on distance between camera and 3D object. Terrain physics simulation researchers need a way to recognize the original object shape from 3D LOD objects. In this paper, we proposed simply automatic LOD framework using point cloud data (PCD). This PCD was created using a 6-direct orthographic ray. Various experiments are performed to validate the effectiveness of the proposed method. We hope the proposed automatic LOD generation framework can play an important role in game development and terrain physic simulation.

Validation and Application of OpenFOAM for Prediction of Livestock Airborne Virus Spread (공기 중 축산질병 확산예측을 위한 오픈폼 도입 및 검증)

  • Roh, Hyun-Seok;Seo, Il-Hwan;Lee, In-Bok
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.1
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    • pp.81-88
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    • 2014
  • Accurate wind data is essential for predicting airborne spread of virus. OpenFOAM was used for computational fluid dynamics (CFD) simulation procedure which is under GNU GPL (General Public License). Using complex terrain, DEM (Digital Elevation Map) that was prepared from GIS information covering a research site is converted to a three dimensional surface mesh that is composed by quad and full hexahedral space meshes. Around this surface mesh, an extended computational domain volume was designed. Atmospheric flow boundary conditions were used at inlet and roughness height and was considered at terrain by using rough wall function. Two different wind conditions that was relatively stable during certain periods were compared in 3 different locations for validating the accuracy of the CFD computed solution. The result shows about 10 % of difference between the calculated result and measured data. This procedure can simulate a prediction of time-series data for airborne virus spread that can be used to make a web-based forecasting system of airborne virus spread.