## algorithmic approach to calculate the area of an irregular polygon, both concave and convex

I am using simple coordinate geometry to initially calculate the area and the length of each edge of an irregular polygon (either concave or convex). Then I have a need to make small changes to the length of any individual edge, but I will not be changing the coordinates coordinates of the edge. So now I have a need to recalculate the area of the new polygon based only on the length of each edge.

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Not sure what you mean by "not changing the coordinates of the edge", but is there something that the surveyor's formula doesn't give you? en.wikipedia.org/wiki/Polygon#Area_and_centroid – jc Apr 19 2010 at 21:30
I don't understand how one could change the length of an edge without changing its coordinates. – Reid Barton Apr 20 2010 at 13:58