Start by drawing two parallel chords through the ellipse. It is easiest to think of these things as apporoximately straddling the center. Bisect these two chords at two points. Connect the segment A with those endpoints. Construct another set of parallel chords, and do the same with that. It is important that the segment B constructed by connecting the midpoints of this second set of chords intersect the first segment. This intersection point will be the center of the ellipse.
From the center, draw a circle of radius larger than the minor axis but smaller than the major axis. It will intersect the ellipse in 4 points: clockwise, from a direction of 0º, W, X, Y, and Z. The segments WX and XY provide the directions for the major axes. Drawing lines parallel to these through the center will give you the major and minor axes.
|
Posted by Eric
on 2004-12-21 17:39:22 |