Polygonal chain
From Wikipedia, the free encyclopedia
A polygonal chain, polygonal curve, polygonal path, or piecewise linear curve, is a connected series of line segments. More formally, a polygonal chain P is a curve specified by a sequence of points 
called its vertices so that the curve consists of the line segments connecting the consecutive vertices.
A simple polygonal chain is one in which only consecutive (or the first and the last) segments intersect and only at their endpoints.
A closed polygonal chain is one in which the first vertex coincides with the last one, or, alternatively, the first and the last vertices are also connected by a line segment. A simple closed polygonal chain in the plane is the boundary of a simple polygon. Often the term "polygon" is used in the meaning of "closed polygonal chain".
In some cases it is important to draw a distinction between a polygonal area and a polygonal chain.
A polygonal chain is called monotone, if there is a straight line L such that every line perpendicular to L intersects the chain at most once. Every monotone polygonal chain is open by definition. Compare with "Monotone polygon".
[edit] Application and problems
Polygonal curves can be used to approximate other curves and boundaries of real-life objects.
