• Title/Summary/Keyword: slope terrain

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A Study on Change of NDVI According to the Terrain Element (지형요소에 따른 NDVI의 변화에 관한 연구)

  • Sung, Chun-Ja;Jung, Jong-Chul
    • Journal of the Korean Association of Geographic Information Studies
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    • v.6 no.2
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    • pp.92-100
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    • 2003
  • Analysis and results of the relationship between the NDVI and terrain element such as elevation, slope, aspect in Chunahn city area are as follows. It does not show the linear relationship between NDVI and analyzed terrain element such as elevation, slope, aspect, etc. and there is a trend such that the deviation of NDVI is decreased as the elevation and slope is increased. It appears that there is trends such that the distribution range of NDVI is discontinuously changed as the elevation and slope is increased. The distribution range of NDVI is discontinuously decreased based on about 50m and 100m borderline in elevation case, and slope $10{\sim}20^{\circ}$ borderline in slope case, respectively. Any special trend is discovered in the relationship between aspect and NDVI.

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Slope Detecting and Walking Algorithm of a Quadruped Robot Using Contact Forces (접촉 반력을 이용한 4 족 보행로봇의 경사면 감지 및 보행 알고리즘)

  • Lee, Soon-Geul
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4 s.97
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    • pp.138-147
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    • 1999
  • For autonomous navigation, a legged robot should be able to walk over irregular terrain and adapt itself to variation of supporting surface. Walking through slope is one of the typical tasks for such case. Robot needs not only to change foot trajectory but also to adjust its configuration to the slope angle for maintaining stability against gravity. This paper suggests such adaptation algorithm for stable walking which uses feedback of reaction forces at feet. Adjusting algorithm of foot trajectory was studied with the estimated angel of slope without visual feedback. A concept of virtual slope angle was introduced to adjust body configuration against slope change of the supporting terrain. Regeneration of foot trajectory also used this concept for maintaining its stable walking against unexpected landing point.

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Slope and Roughness Extraction Method from Terrain Elevation Maps (지형 고도 맵으로부터 기울기와 거칠기 추출 방법)

  • Jin, Gang-Gyoo;Lee, Hyun-Sik;Lee, Yun-Hyung;So, Myung-Ok;Shin, Ok-Keun;Chae, Jeong-Sook;Lee, Young-Il
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.9
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    • pp.909-915
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    • 2008
  • Recently, the interests in the development and application of unmaned robots are increasing in various fields including surveillance and reconnaissance, planet exploration, and disaster relief. Unmaned robots are usually controlled from distance using radio communications but they should be equipped with an autonomous travelling function to cope with unexpected terrains and obstacles. This means that they should be able to evaluate terrain's characteristics quantitatively using mounted sensors so as to traverse harsh natural terrains autonomously. For this purpose, this paper presents a method for extracting terrain information, that is, slope and roughness from elevation maps as a prior step of traversability analysis. Slope is extracted using the curve fitting based on the least squares method and roughness using three metrics and their weighted average. The effectiveness of the proposed method is verified on both a fractal map and the world model map of a real terrain.

Comparative Analysis of Terrain Slope Using Digital Map, LiDAR Data (수치지형도와 LiDAR 데이터를 이용한 지형경사도 비교분석)

  • Kang, Joon-Mook;Yoon, Hee-Cheon;Min, Kwan-Sik;Rhee, Won-Yong
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.4
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    • pp.3-9
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    • 2007
  • Recently, the efforts of systematic understanding and utilization of geographic phenomenon for human life as a important factor among activity of mankind are increasing. It is necessary to express topography connected with space. Especially, the technology of geographic analysis using DEM can supply the information rapidly and accurately about elevation and terrain slope of the subject area under the necessity of high 3D quality geographic information. In this study, creating more precise DEM derived from LiDAR data, quantitative analysis on the subject area about elevation and terrain slope is done under comparison with Digital Topographic map Scale 1:1000. LiDAR data is more detailed than Digital Topographic map to express the elevation of the subject area ($39.89{\sim}77.48m$), and terrain slope by analysis using DEM derived from LiDAR data come out minutely about 90%. It can be concluded that the LiDAR data is very applicable and accurate for 3D topographic terrain slope analysis.

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Design of an Electric Wheelchair Control Algorithm by Slope Recognition on uneven terrain (비평탄 지형에서의 경사 인식을 통한 전동 휠체어 제어 알고리즘 개발)

  • Kong, Jung-Shik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.9
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    • pp.5738-5743
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    • 2014
  • This paper evaluated an electric wheelchair control algorithm by slope recognition on uneven terrain. Nowadays, the population using wheelchair has been increasing rapidly due to increases in the elderly population. On the other hand, most wheelchairs are directly controlled by the user without any device capable of securing the safety of the user. This causes difficulties in wheelchair control from the influence of gravity on the slope. This paper proposes a vehicle control algorithm that can move a wheelchair similar to moving on a plane. At that time, sensors are not used to recognize the degree of the slope. All processes were verified by simulation.

The Effect of Grid Size in a Slope Analysis of Terrain by DEM for Hydrological Analysis (수문해석을 위한 DEM에 의한 지형의 경사도분석에서 격자크기의 영향)

  • 양인태;김연준
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.15 no.2
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    • pp.221-230
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    • 1997
  • In hydrology analysis, the result of a slope analysis for terrain have an very important effect on water quality and water quantity Recently, a slope analysis tend to use the digital elevation model rater than the traditional map sheet. But a terrain slope analysis by the digital elevation model depends on grid size of the digital elevation model. Hence the effect of a slope analysis by the digital elevation model is a important factor. In this study, therefor, in order to determine a hydrological parameter and a terrain parameter for simulation of the water quality and the hydrological property, we adapted two sample area that are the Nerin stream of the basin of the Soyang lake and a Osip stream of Samchuk, and its individual coverages are $640\;km^2$ and $33\;km^2$. Also to analyze the effect of grid size in the slope of a basin, we apply DEM changing a grid size respectively at intervals of 100 m from 100 m to 1.000m for the Nerin stream basin and at intervals of 10 m from 20 m to 300 m for the Osip stream basin.

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A Numerical Simulation Study on the Sensitivity of WRF Model in the Wind Field to the Steepness of Mountain Slopes (산 경사면의 기울기 변화에 따른 바람장의 민감도에 관한 WRF 수치모의 연구)

  • Han, Seon-Ho;Lee, Jae Gyoo
    • Atmosphere
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    • v.17 no.4
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    • pp.349-364
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    • 2007
  • The main purpose of this study is to examine the sensitivity of the WRF (Weather Research and Forecasting) in the wind field to the steepness of mountains in the case with a strong downslope wind occurred in the Yeongdong province. We conducted WRF simulations for February 13 2006. The initial and boundary data are from the NCEP/NCAR $1^{\circ}{\times}1^{\circ}$ GDAS. Arbitrary terrains of the mountains with a symmetric orography and an asymmetric one with steeper leeward slope, were introduced to examine the sensitivity of the shape of the mountains. The simulation with an asymmetric terrain results in stronger maximum surface wind by about $10ms^{-1}$ than with a symmetric terrain, especially in the narrow region from the peak to ~ 4 km away in the downstream. However, the maximum surface wind speed is weaker by $20ms^{-1}$ than with a symmetric terrain away from the narrow peak region. This indicates that the steeper slope leads to the intensification of downslope wind in the narrower region leeward. In addition, for the simulation with an asymmetric terrain, the strength of wave breaking is greater and the Lee wave is more dominant than for that with a symmetric terrain.

Misclassified Area Detection Algorithm for Aerial LiDAR Digital Terrain Data (항공 라이다 수치지면자료의 오분류 영역 탐지 알고리즘)

  • Kim, Min-Chul;Noh, Myoung-Jong;Cho, Woo-Sug;Bang, Ki-In;Park, Jun-Ku
    • Journal of Korean Society for Geospatial Information Science
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    • v.19 no.1
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    • pp.79-86
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    • 2011
  • Recently, aerial laser scanning technology has received full attention in constructing DEM(Digital Elevation Model). It is well known that the quality of DEM is mostly influenced by the accuracy of DTD(Digital Terrain Data) extracted from LiDAR(Light Detection And Ranging) raw data. However, there are always misclassified data in the DTD generated by automatic filtering process due to the limitation of automatic filtering algorithm and intrinsic property of LiDAR raw data. In order to eliminate the misclassified data, a manual filtering process is performed right after automatic filtering process. In this study, an algorithm that detects automatically possible misclassified data included in the DTD from automatic filtering process is proposed, which will reduce the load of manual filtering process. The algorithm runs on 2D grid data structure and makes use of several parameters such as 'Slope Angle', 'Slope DeltaH' and 'NNMaxDH(Nearest Neighbor Max Delta Height)'. The experimental results show that the proposed algorithm quite well detected the misclassified data regardless of the terrain type and LiDAR point density.

The Analysis of Terrain and Topography using Fractal (프랙탈 기법에 의한 지형의 특성분석)

  • Kwon, Kee-Wook;Jee, Hyung-Kyu;Lee, Jong-Dal
    • Journal of the Korean association of regional geographers
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    • v.11 no.6
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    • pp.530-542
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    • 2005
  • In this study, GIS method has been used to get fractal characteristics. Using the projected area and surface area, 2 dimensional fractal characteristic of terrain was found out. Correlation of fractal dimension and mean slope were also checked over. Results are as below. 1) To get a fractal dimension, the method which is using the surface area is also directly proportional to complexity of the terrain as other fractal dimension. 2) Fractal dimensions using the surface area, that is proposed in this thesis are carried out as below : Uiseong : $2.02{\sim}2.15$ Yeongcheon : $2.10{\sim}2.24$. These values are in a range of fractal $2.10{\sim}2.20$ dimensions which has known. 3) Correlation of mean slope and fractal dimension is diminished about 30% in a region which is more than $25^{\circ}$ of mean slope. So, in this region using the fractal dimension method is better than using the mean slope. From this study, on formula using the projected area and surface area is still good to get a fractal dimension that has been found. But to confirm this method the region of research should be wider and be set up the correlation of mean slope, surface area and fractal dimension. It can be applicable to restoration of terrain and traffic flow analysis in the future research.

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Analysis of the Effect on the Location Evaluation of Golf Course according to the Unit Grid Size applied in the Slope Analysis(In flank of Environment) (경사도 분석에 적용하는 단위격자크기가 골프장의 입지 평가에 미치는 영향 분석(환경적 측면에서))

  • Um, Dae Yong;Lee, Beung Soo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.30 no.5
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    • pp.467-475
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    • 2012
  • In this study, the problems were analyzed that derived a different position evaluation results depending on the unit grid size that are applied to the terrain slope analysis conducted to assess the its position and environmental impacts in the prior environment reviewing process of golf course construction projects. For this purpose, the unit grid size were analyzed that can precisely reflect a actual terrain by analyzing the change of a slope percentage according to the change of unit grid size about 12 golf courses is currently in progress of construction work through the environmental consultation or ongoing consultation. And the consultation availability of environmental assessment was reverified by applying the unit grid size derived through this study about a study golf course. In the result of study, the bigger grid size for slope analysis is set, the greatly gradient is changed and the slope ratio of the higher elevation was lowly evaluated in comparison with actual terrain. The analytical result that most closely match the actual terrain was extracted in the case applied $5m{\times}5m$ of the unit grid sizes setting in this study. So, we proposed this study results to the ministry of environment and could be amended the unit grid size of $5m{\times}5m$ as standard for the analysis of slope. Also, if new grid size for site evaluation is applied to the study sites, 4 sites exceed the standard suggested the existing regulations and they are not proper as golf course site in flank of environment.