What are Stereonets used for?
A stereonet allows the stereographical projection of three-dimensional information onto a two-dimensional plane (usually as a piece of paper or computer image) and is used as a tool applied to a range of geological problems including the removal of structural tilt.
How do you plot a stereographic projection?
To plot a face, first measure the Φ angle along the outermost great circle, and make a mark on your tracing paper. Next rotate the tracing paper so that the mark lies at the end of the E-W axis of the stereonet. Measure the ρ angle out from the center of the stereonet along the E-W axis of the stereonet.
What is pole in stereographic projection?
The pole is a line running through the center of the projection sphere and perpendicular to the plane (fig. 2-9). The pole forms a 90° angle with the strike line and a 90° angle with the dip line. Thus, the pole will always be found in the opposite quadrant of the stereonet from the dip of the plane.
What is stereographic projection in crystallography?
Stereographic projection is a method used in crystallography and structural geology to depict the angular relationships between crystal faces and geologic structures, respectively. Here we discuss the method used in crystallography, but it is similar to the method used in structural geology.
What is great circle in stereographic projection?
The line of intersection between the plane and the sphere will then represent a circle, and this circle is formally known as a great circle. Except for the field of crystallography, where upper-hemisphere projection is used, geologists use the lower part of the hemisphere for stereographic projections, as shown in Fig.
What is stereographic projection in complex analysis?
The stereographic projection is a mapping that projects the sphere onto a plane. This projection is defined on the whole sphere, except at the projection point.
What is rake on stereonet?
Rake is simply the angle between the strike direction and the lineation trend. You can figure this out simply on a stereonet by just counting the grid squares along the great circle line. Rakes of 0° are at North and South, while a rake of 90° is in the middle.
What is a pole in stereographic projection?
What is the source of light in stereographic projection?
At the opposite end where the tangent plane touches the reference globe is the light source for the stereographic projection. This map projection is commonly used for polar aspects and navigation maps because of how it preserves shapes (conformal).
How do you find the trend and plunge of a stereonet?
Determing the Trend and Plunge of a Line from a stereonet 1) Rotate the tracing paper such that the point representing the 3-D line is along the North-South axis of the stereonet. 2) To determine the plunge, count the grid squares between North and the intersection point.
What is stereographic net?
The stereographic net or stereonet is the 3-D equivalent of a protractor. It is used to measure angles on the projection. To measure angles, we need to rotate the net relative to the tracing paper.
What is a stereographic net used for?
In practice, the projection is carried out by computer or by hand using a special kind of graph paper called a stereographic net, shortened to stereonet, or Wulff net . Illustration by Rubens for “Opticorum libri sex philosophis juxta ac mathematicis utiles”, by François d’Aguilon.
What was the stereographic projection used for?
One of its most important uses was the representation of celestial charts. The term planisphere is still used to refer to such charts. In the 16th and 17th century, the equatorial aspect of the stereographic projection was commonly used for maps of the Eastern and Western Hemispheres.
How do you find the area-distorting property of stereographic projection?
In the figure, the area-distorting property of the stereographic projection can be seen by comparing a grid sector near the center of the net with one at the far right or left. The two sectors have equal areas on the sphere.
Is stereographic projection conformal or isometric?
It is conformal, meaning that it preserves angles at which curves meet. It is neither isometric nor area-preserving: that is, it preserves neither distances nor the areas of figures. Intuitively, then, the stereographic projection is a way of picturing the sphere as the plane, with some inevitable compromises.