地質圖之自動化製作探討

Abstract

等高線與數值地形模型之應用，向來為各類土木工程規劃設計所不可或缺的基本技術，本研究引用數值地形模型之概念，將地形面資料以Natural Neighbor Proximal Order排序法建構出唯一之地形空間曲面網格產生數值地形面，並以區域重心座標法內插等高線繪製地形圖。同時，由露頭量測或者鑽孔資料所得之位態條件，以幾何方程式以及曲面參數式B-Spline內插法建構出單斜構造、理想對稱褶皺、一般不規則曲面以及斷層構造等地層面模型，應用兩種模型的空間關係以求得地層面露頭線，繪製地質圖及剖面圖。利用Visual Basic語言來研擬出一可行的資料結構及運算流程，以期建立一具完整性的地質圖自動化製作功能程式。 本研究在地層構造的模擬上，多採B-Spline參數式來模擬較複雜的層面，在連續一般曲面與斷層構造部分，皆以參數式架構來處理，建立具有層面特徵之網格，再以參數內插來建構出數值地層面。參數化曲面對於複雜層面分析來說具有相當的可行性，以參數遞迴做線性內插去直接求得符合地層特徵網格每個節點值的曲面，充分利用電腦數值運算的能力，節點值可紀錄測點位態條件後，其較方程式應用上更能符合地層面特徵，也可靈活去處理層面間的修正。

This study aims to study the possibility to generate geological maps by computerized methods. To begin with, a unique surface grid with "natural neighbor proximal order" and contour are constructed from digital terrain model (DTM). Furthermore, the geological formation models (such as monoclines, folds, and faults) are constructed by geometric functions or B-Spline interpolation. The construction of a geological model will make use of bedding information including orientations data from outcrops and rock-cores. From the DTM and the geological model, it is then possible to obtain the geologic boundaries (or contact lines), and to draw a geological map or profile. Using the above-mentioned concepts, a computer program is developed to construct geological maps for practical usage. The presented work makes uses of the B-Spline to simulate complex formations. The following approach can be carried out. First, a grid representing the feature of a bedding boundary (of the geological formation) is constructed. Subsequently, the model of a non-planar bedding boundary can be constructed by the parametric interpolation. The geological map then can be obtained by overlaying the contour representing the DTM and all geological boundaries (bedding boundaries) on a same map. The grid values obtained from B-Spline and parametric interpolation generally fit the feature of the geologic boundaries. The presented method is found suitable for modeling part of the geologic boundaries, and is more flexible while adjusting between geologic boundaries.