coordinate system


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The Four Main Coordinate Systemsclick for a larger image
The Four Main Coordinate Systems
coordinate systemclick for a larger image
coordinate system

coordinate system

() A system, resembling that of latitude and longitude on the Earth, by which the direction of a celestial body or a point in the sky can be specified. The direction is defined and determined by two spherical coordinates, referred to a fundamental great circle lying on the celestial sphere and a point on the fundamental circle (see illustration). One coordinate (a) is the angular distance of the celestial body measured perpendicular to the fundamental circle along an auxiliary great circle passing through the body and the poles of the fundamental circle. The other coordinate (b) is the angular distance measured along the fundamental circle from a selected zero point to the intersection of the auxiliary circle.

There are four main coordinate systems: the equatorial, horizontal, ecliptic, and galactic coordinate systems (see table). They are all centered on the Earth. Transformations can be made from one system to another by means of the relationships between the angles and sides of the relevant spherical triangles. The astronomical triangle, for example, relates equatorial and horizontal coordinates; the triangle formed by the celestial body and the poles of the equator and ecliptic relates equatorial and ecliptic coordinates. See also heliocentric coordinate system.

References in periodicals archive ?
On the lateral surface of the skull, a rectangular coordinate system was established by a horizontal line (X-axis) and a vertical line (Y-axis).
The element stiffness matrices of GQ12 and GQ12M under the local coordinate system are described in the above section, and these matrices can be numerically calculated by the Gaussian integral method.
The coordinate system placement for the determination of the transformation matrix is shown in Fig.
transformation of image coordinate system according to the patient coordinate system and image slice positions, which are required to correctly interpret the structures.
An important element to consider, is how to find the coordinates of an event point (earth like planet) with respect to the coordinate system (K).
b]) is the angle cosine of the X axis of coordinate system A with the X axis of coordinate system B.
1] is the position vector of the weaving path relative to the world coordinate system.
In sweep-based modeling, it is necessary to define a local coordinate system on a trajectory curve, and in general this can be supplied by the Frenet frame [1]; but Frenet frames flip at inflection points, where the second derivatives of the curve equations vanish.
Suppose the target position in coordinate system XYZ is (X, Y, Z), then the corresponding coordinates in coordinate system UVW is
The LKS94 national geodetic coordinate system that is presently used in Lithuania is the realisation of the ETR89 European geodetic coordinate system in Lithuania (Skeivalas 2008; Zakarevicius 1994; Zakarevicius 2003).
Relation between an angular velocity of the body in the body coordinate system and the derivative of the vector of Cardan angles by time is equal:
The arm and the tracker take simultaneous measurements of the arm's position and automatically juxtapose the two coordinate systems.