Spider Web chart?

[David Epstein]

Richard Gaskin asked for code useful for making a spider web chart.  I think the function below would help.  Both the grid and the plots will be polygons whose points can be conveniently specified by their distance from an origin and their angle on a circle.

function yAD x,y,d,a, at xAD
  -- calculate point x1,y1 that is distance d and angle a from point x,y
  -- return y1, load x1 into param 5
  -- a is in degrees, positive is east of north
  put (90-a)*2*pi/360 into a
  put x + d*cos(a) into xAD
  return y + d*sin(a)
end yAD


David Epstein