Fault data are plotted separately, showing the fault plane as a great circle and lineations as dots on that great circle.

The angle between the fracture sets can be found by counting degrees along the great circle that ﬁts both data sets. Plotting bedding orientations reveals the b-axis (local orientation of the hinge line). A constructed, but realistic, situation where various structural elements in a deformed rock sequence are represented in stereonets. Back-rotate the overlay, and the task is completed (Fig. Now count the plunge value along the straight line toward the center, starting at the primitive circle, and mark off the pole (Fig. 8b), or until it reaches the E direction (a clockwise rotation of 60 degrees for our example). 8a), rotate the overlay either 30 degrees anticlockwise, as for the plane (Fig. As for the plane, we mark off the trend (030) (Fig. For example, a line plunging 40 degrees toward 030 (NE) is considered. Plotting a line orientation is similar (but different) to plotting a plane orientation. Contouring is easily done by means of one of the many computer programs available for personal computers. 6), and the contour values exhibit the number of points as the percentage within a given 1% area of the stereonet. Contouring is typically done for crystallographic axes such as quartz c-axes (Fig. Multiple data plotted in an equal area net can be contoured with respect to density, which can be useful when evaluating concentrations of structural data around certain geographic directions. The net is called a Schmidt net or simply an equal area net (Fig. 4), the positions of planes and lines in the plot become somewhat different. The method of plotting is the same, but because the projection is not stereographic but equal area (Fig. However, for most structural purposes it is more useful to preserve area, so that the densities of projections in one part of the plot can be directly compared to those of another. The Wulff net makes it possible to work with angular relations (it preserves angles between planes across the net), which can be useful in some cases, for instance for crystallographic purposes.

Rose diagram geology