Returns the area of a polygon. The area is positive if the vertices are defined in a counter-clockwise direction, and negative if the vertices are defined in a clockwise direction.
The polygon vertices are contained in a single matrix of dimension Nx2 (or 2xN), where N >= 3 is the number of vertices. The dimension 2 corresponds to the x,y positions. For example, a square of side length 1 can be described by V = [ 0,0; 1,0; 1,1; 0,1] or V = [ 0,1,1,0;0,0,1,1].
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Syntax |
Description |
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out = polyarea(V); |
Returns the area of V. The sign of the area indicates if V is defined in a counter-clockwise (positive) or clockwise (negative) direction. |
Example
Calculate the area of a square of side length 1:
V = [ 0,0; 1,0; 1,1; 0,1]; ?polyarea(V); result: 1
See Also
List of commands , centroid , polyintersect , inpoly , polygrow , polyand , polyor , polydiff , polyxor