Lambert azimuthal equal-area projection#Schmidt net

The ' Schmidt net' or ' attitude sphere ' is a tool for representing geological or crystallographic direction data, conceived by Walter Schmidt ( 1925). This is a geometric technical term. Since these data represent, in most cases, only directions and thus no defined amount (eg length), they can be regarded as one vectors. Can you start all these vectors one at one point, so their tips lie on a spherical surface, the ball position. Linear (ie linear ) elements are in the form of the contact point ( intersection point ) of the vector drawn to the ball surface. Scale elements are represented by the point where the surface normal with the attitude sphere. The position of such a point is specified as well as the geographical position of a point on the earth's surface by longitude and latitude lines. A two-dimensional element can be represented by a great circle (ie, vertical) is perpendicular to the intersection point of the surface normal.

Application

The great advantage of the attitude sphere representation lies in the comparison of different data sets and the ability to perform a wide range of geometric operations on those data. Also, can the geometry of geological bodies with this tool to determine very clearly. In crystallography, the attitude sphere is an important tool to demonstrate the symmetry relations of crystallographic surfaces and axes clearly. In the presentation of geological issues on the ball position but you have to be aware that the geographical location of each element shown is lost and only its direction remains. So you can, for example, Anticlines and synclines ( = geological folds) do not differ on the ball position.

Since most data structures are bipolar axes, generally meets display on a hemisphere. In geology, usually the lower hemisphere is used, while crystallographic elements are usually represented in the upper hemisphere. The position of the ball is also great for displaying large amounts of data, for which the direction of statistical parameters on the ball position can be determined. In order to clearly and unambiguously represent the attitude sphere in a plane of the drawing, using different attitude sphere projections.