Illustrate the term winding number

Question

Illustrate the term winding number?

Answer 1

To ensure whether a specified point is inside or outside the polygon, winding number method is used. The edges which are cross the scan line, this method give a direction number to all. As if the edge starts below the given line and ends above the given line shows direction as -1 otherwise 1. When the value of winding number is nonzero for polygons as well as two dimensional objects point is defined as it is inside.