Figure 6. Surface classification and fracture orientation of area 1, Big Rock Quarry. (A) High-resolution image of the outcrop with fracture planes clearly visible. (B) Surface geometry of the outcrop is remotely captured from a dense 3-D point cloud (7212 points) and displayed here as a triangulated mesh. Distinct orientations are shown as color-coded point clouds, where each color represents a particular orientation, red (NE) and green (NW). (C) Seven clusters, corresponding to the identified orientations, are shown as color-coded point clouds. Three primary fracture orientations were observed: NE- (red), NW- (green), and NNW-striking (yellow) fracture sets. The bedding is displayed in black. The green (NW) and red (NE) planes are nearly orthogonal to each other, and both of them are perpendicular to bedding. (D) The optimum number of seven clusters in the final partition is determined by the L-shaped break value of the minimum description length (MDL) criterion. (E) Equal-area stereographic projection of the orientation data. The distribution of poles to the planes defined in the pass 1 partition indicates that there is more variation in strike orientation within each cluster than in dip. Mean vectors for each cluster are plotted as circles.