2004 Fiscal Year Final Research Report Summary
Development of Theory and Algorithm to Define Geometrical Elements of Three-dimensional Geologic Structure in a Form Suitable for Application in GIS and CAD Environments
| Project/Area Number |
14540430
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geology
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| Research Institution | Osaka City University |
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Principal Investigator |
SHIONO Kiyoji Osaka City University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (40047387)
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| Co-Investigator(Kenkyū-buntansha) |
MASUMOTO Shinji Osaka City University, Graduate School of Science, Ass. Professor, 大学院・理学研究科, 助教授 (40173760)
RAGHAVAN Venkatesh Osaka City University, Graduate School for Creative Cities, Ass. Professor, 大学院・創造都市研究科, 助教授 (30291602)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Geologic Structure / Topology / Geologic Boundary / Boundary Surface / Geologic Function / Neighborhood / GIS / CAD |
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| Research Abstract |
The spatial distribution of every geologic unit within a 3-D space under consideration is expressed as a subspaces bordered by surfaces that divides the space into two subspaces. This relation between geologic units and boundary surfaces has been called a logical model of geologic structure. Given the logical model and DEMs of surfaces, we can define the geologic function that assigns to every point a unique geologic unit that contains the point. The purpose of the present study is to develop the theory and algorithm to extract information on geometrical elements such as boundary lines and surfaces from 3疋 model of geologic structure specified by the logical model and the DEMs. The results are summarized as follows :
1. The distribution of geologic units defines a partition of a 3D space. Introducing the topological concept, we found that a boundary of geologic units can be formulated as an intersection of their closures.
2. It was proved that the above idea is useful to visualize geologic boundaries in a raster image through masking procedures in the GIS environment.
3. We defined a function that assigns to every point a pair of geologic unit just below the point and one just above the point. The function is useful to judge whether a point lies within a geologic unit or on the boundary. We included an algorithm to draw a line of geologic boundary in a software for visualization of 3-D geologic model.
4. We further defined a function that assigns to every point a set of geologic units neighboring around the point. As an application of the function, we developed an algorithm to find boundary lines appearing on a specified surface and to output them as a data file suitable for GIS and CAD system.
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