Area of a irregular shape

Question

I have set of points which lies on the image. These set of points form a irregular closed shape. I need to find the area of this shape. Does any body which is the normal algorit

Answer 1

Note: If you don't know the order of the points and cannot guarantee that your polygon is convex, it is not possible to determine the ordering of the shape, since there may be more than one possible order the points which produces a polygon. If you do know that the polygon is convex, determining the ordering of the points is easy. Merely sort the points by angle from one particular point., with the first point being the one that forms a line between itself and the initial point such that all the other points are on the same side of the line. The triangles formed by this process can also be used to calculate the area.