Editing Coordinate system (section)

==Orientation-based coordinates==
In [[geometry]] and [[kinematics]], coordinate systems are used to describe the (linear) position of points and the [[orientation (geometry)|angular position]] of axes, planes, and [[rigid body|rigid bodies]].<ref>{{cite book |title=Analytical Mechanics of Space Systems |author1-link=Hanspeter Schaub |author2-link=John Junkins |author1=Hanspeter Schaub |author2=John L. Junkins |chapter=Rigid body kinematics |page=71 |chapter-url=https://books.google.com/books?id=qXvESNWrfpUC&pg=PA71 |isbn=1-56347-563-4 |year=2003 |publisher=American Institute of Aeronautics and Astronautics}}</ref> In the latter case, the orientation of a second (typically referred to as "local") coordinate system, fixed to the node, is defined based on the first (typically referred to as "global" or "world" coordinate system). For instance, the orientation of a rigid body can be represented by an orientation [[Matrix (mathematics)|matrix]], which includes, in its three columns, the [[Cartesian coordinates]] of three points. These points are used to define the orientation of the axes of the local system; they are the tips of three [[unit vector]]s aligned with those axes.