• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.4
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• pp.61-71
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• 2001

In these days, surveying instruments are developing rapidly and the precision is improving continuously. The reappearance of three dimensional terrains of a great precision are possible and the calculation of the area or the volume has a high precision due to the development of the technique of the spatial information system using computer. But actually, in construction site they calculate two-dimensional area using the traditional method, plane table surveying, planimeter, and then get ground surface area through timing the slope correction factor. In this study, I show the defect and inefficiency of the calculation of the area by the traditional methods and survey the area with Electronic Distance Measuring equipment and GPS instrument. With these data, we made the three dimensional terrain model and calculated two-dimensional area and ground surface area. After that, I compared areas that calculated by algorithm method of irregular triangle and analysis of grid method with standardizing the area that calculated by the traditional method. Finally, I suggested more effective and precise method in calculating ground surface area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.3
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• pp.227-237
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• 2022

The most critical factors for detecting changes in very high-resolution satellite images are building positional inconsistencies and relief displacements caused by satellite side-view. To resolve the above problems, additional processing using a digital elevation model and deep learning approach have been proposed. Unfortunately, these approaches are not sufficiently effective in solving these problems. This study proposed a change detection method that considers both positional and topology information of buildings. Mask R-CNN (Region-based Convolutional Neural Network) was trained on a SpaceNet building detection v2 dataset, and the central points of each building were extracted as building nodes. Then, triangulated irregular network graphs were created on building nodes from temporal images. To extract the area, where there is a structural difference between two graphs, a change index reflecting the similarity of the graphs and differences in the location of building nodes was proposed. Finally, newly changed or deleted buildings were detected by comparing the two graphs. Three pairs of test sites were selected to evaluate the proposed method's effectiveness, and the results showed that changed buildings were detected in the case of side-view satellite images with building positional inconsistencies.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.601-603
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• 1999

대부분의 다면체 모델 데이터의 표면과 지리 정보 시스템을 위한 지형 데이터는 삼각 분할을 통하여 만들어진 불규칙 삼각형 네트웍(Triangulated Irregular Network:TIN) 구조를 가지고 있다. 대용량 TIN 데이터를 그래픽스 시스템에서 빠르게 시각화 하는데는 많은 어려움이 있으므로, 일반적으로 TIN 데이터의 특징을 이용하여 압축된 데이터를 이용한다. 그러나 압축한 TIN 데이터는 부분적인 수정과 같은 연산을 수행하기 위하여 전체 데이터를 디코딩하고 다시 인코딩하는 과정을 반복하여 수행하므로 이같은 연산이 자주 발생하는 응용분야에는 부적합하다. 본 논문은 이러한 문제의 해결방안으로 삼각형 메쉬를 삼각형 스트립으로 재구성 한 후에 이 삼각형 스트립을 정점 체인과 각 정점의 차수 정보를 이용하는 저장하는 압축 알고리즘과 함께 이 알고리즘이 부분적인 불규칙 삼각망 수정에 유용하게 적용될 수 있음을 제시한다. 제안된 알고리즘은 각각의 정점 체인이 독립적으로 인코딩 가능하므로 불규칙 삼각망 정보를 수정할 경우 최소한의 인코딩과 디코딩으로 불규칙 삼각망을 수정할 수 있다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.533-540
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• 2006

In recent years, civil-engineering work is desired the terrain information to be more efficient in earthwork volume calculation. One method for collecting elevation data is LiDAR. Lidar data was used to produce rapidly an accurate digital elevation model of the terrain, compared with the conventional ground surveys, photogrammetty, and remote sensing. Raw Lidar data is combined with GPS positional data to georeference the data sets. Lidar data is edited and processed to generate surface models, elevation models, and contours. Here we can either create a Tin Volume Surface or a Gird Volume Surface. Triangulated Irregular Network(TIN) has complex data structure, but it can describe well terrain surface features. As we have seen, we search the efficiency for earthwork volume calculation using Lidar data. One conclusion we can draw from this study is that Lidar data is more accurate result than digital map in the calculation of earthwork volume.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.28-36
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• 2000

A TIN, Triangulated Irregular Network, based topographic modeling method and a distributed rainfall-runoff model using the topographic representation is presented. In the TIN based topographic representation, a watershed basin is modeled as a set of contiguous non-overlapping triangular facets: the watershed basin is subdivided according to streamlines to deal with water movement one-dimensionally; and each partitioned catchment is approximated to a slope element having a quasi-three-dimensional shape by using cubic spline functions. On an approximated slope element, water movement is represented by combined surface-subsurface kinematic wave equations considering a change of slope gradient and slope width. By using the distributed rainfall-runoff model, the effects of spatial variability of soil properties on runoff response are examined.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.40-48
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• 2011

The purpose of this study is to contribute enhancing the accuracy of viewshed analysis through the explanation for an analysis method of viewshed analysis using GIS. According to previous studies, the visible area using digital terrain in viewshed analysis depends on a visible interest area, scale of terrain, spatial resolution and surface data. In this study, we used trend analysis and RMSE analysis in order to find the effect of a visible interest area, scale of terrain, etc in viewshed analysis. Results of this study are as follows. First, the result of viewshed analysis depends on a visible interest area, scale of terrain, spatial resolution, surface data such as previous studies. Second, the results in forest area are reliable than those of flat area in terms of a visible interest area. Third, the results based on raster grid data are stable than those of TIN(triangulated irregular network) in terms of input surface data. Fourth, according to the result of trend and RMSE analysis, the spatial resolution for analysis is differently applied to different scales digital terrain map in viewshed analysis. In detail, it is desirable that the spatial resolution is set less than 10m(in the case of 1/1,000 digital terrain map), 20m(in the case of 1/5,000 map), 30m(1/25,000 map).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.3
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• pp.261-269
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• 2006

There is a need to restore the terrain back its natural environment after mining development. It is necessary to compare the original and developing surfaces for post-management and to analyze the terrain change to develop a process for efficient restoration plan. This study analyzes and compares change to the terrain by annual mining development using GIS. Contours digitized with CAD based on photogrammetry are classified into annual data and created by Triangulated Irregular Network (TIN). By producing profiles and cross sections using TIN, many stations are distinguished. As a result of the terrain changes caused by mining development from 2000 to 2003 by operating elevation values each cell converted to raster from TIN, $11,094,460m^3$ are cut and $5,127,968m^3$ are filled up to 46% of cut volume, and annual surface changes of cut and fill area to mining are analyzed to visual and quantitative data. This study is used for the restoration plan and additional mining. And it is expected that this annual change, caused by mining development, can be used to return the terrain close to its original condition for finished mining area.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.6
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• pp.463-474
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• 1997

Metallic elements in dustfall have been known as notable air pollutants directly or indirectly influencing human health and wealth. The first aim of this study was to obtain precise spatial distribution patterns of 5 elements (Pb, Zn, K, Cr, and Al) in dustfall around Suwon area. To predict isometric lines of metal fluxes deposited on unsupervised random sites, the study has applied both spatial statistics as a receptor model and a GIS (geographic information system). Total of 31 sampling sites were selected in the study area (roughly 3 by 3 km grid basis) and dustfall samples were then collected monthly basis by the British deposit gauges from Dec., 1995 to Nov., 1996. The metallic elements in the dustfall were then analyzed by an atomic absorption spectrometer (AAS). On the other hand, a base map overlapped by 7 layers was constructed by using the AutoCAD R13 and ARC/INFO 3.4D. Four different spatial interpolation and expolation techniques such as IDW (inverse distance weighted averaging), TIN (triangulated irregular network), polynomial regression, and kriging technique were examined to compare spatial distribution patterns. Each pattern obtained by each technique was substantally different as varing pollutant types, land of use types, and topological conditions, etc. Thus, our study focused intensively on uncertainty analysis based on a concept of the jackknife and the sum of error distance. It was found that a kriging technique was the best applicalbe in this study area.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.81-95
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• 2009

The CDB(Constraint Database) model is a new paradigm for massive spatial data processing such as GIS(Geographic Information System). This paper will identify the limitation of the schema structure and query processing through prior spatial database research and suggest more efficient processing mechanism of constraint data model. We presented constraint model concept, presentation method, and the examples of query processing. Especially, we represented TIN (Triangulated Irregular Network) as a constraint data model which displays the height on a plane data and compared it with prior spatial data model. Finally, we identified that we were able to formalize spatial data in a simple and refined way through constraint data modeling.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.151-157
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• 1996

This study, experimentally, aims at presenting the methodology to construct an efficient digital terrain by com-paring and analyzing the accuracy among the existing Digital Terrain Models, develope 3-D fractal terrain model-ling program by applying digital algorithm of fractal geometry and using turbo pascal, and lastly perform basic research on constructing GSIS-based 3-D fractal terrain modelling system by integrating a PC-based GSIS Pack-age and the 3-D fractal terrain modelling program developed by this paper. The results are as follows -First, the method to produce TIN(Triangulated Irregular Network) by the combination of point data and line data was showed as an alternative to construct efficient Digital Terrain Model. Second, developing GSIS-based 3-D fractal terrain modelling system, applying fractal geometry is the basic research in developing the new terrain modelling method. also, this study presented the possibility of 3-D terrain modelling with the use of fractal.