How do I calculate the area of a 2d polygon?

Question

Assuming a series of points in 2d space that do not self-intersect, what is an efficient method of determining the area of the resulting polygon? As a side note, this is not homework and I am not looking for code. I am looking for a description I can use to implement my own method. I have my ideas about pulling a sequence of triangles from the list of points, but I know there are a bunch of edge cases regarding convex and concave polygons that I probably won't catch.

Answer 1

When measuring a quadrilateral triangle multiply the base by the height. That is a rt angle on the hypotenuse to angle "c". Cut it in half bh/2.