andru@electron.lcs.mit.edu (Andrew Myers) (02/05/91)
In article <Feb.3.19.12.39.1991.10354@pilot.njin.net> psomu@pilot.njin.net (Prabhakar Somu) writes: >Hi, > > I am trying to find the area of an arbitrarily shaped polygon >drawn on the overlay plane on a 4D 70GT(running Irix 3.2). [...] There's no need to use graphics to find the area of a polygon. Given Xi, Yi, the area is sum from i=1,n with j=i+1 except j=1 when i=n: (1/2) (Xj Yi - Xi Yj) Of course, the 1/2 can be factored out. This will give negative values for clockwise polygons, if I've got the signs right, so take the absolute value if appropriate. Andrew