Math question: How to compute the area of polygons

[Jim Hurley]

P.S.

Malte,

One caveat. The algorithm  in my previous message assumes the polygon 
is simply connected--all points accessible without crossing the 
boundary. It calculates the area of a polygon transversed in the 
counter-clockwise sense as positive, and negative if transversed in 
the clockwise sense. Thus the area of a symmetric figure eight-like 
polygon would  be zero.

But this complication can be overcome if it  is an issue.

Jim