Projection Method

There are two different Projection options:

• Equal Angle
• Equal Area

Equal Angle

For the Equal Angle projection method, a line is drawn from the center of the top of the sphere (the zenith), to a point A on the sphere (a pole or a point on the great circle). The intersection of this line with a horizontal plane through the center of the sphere, defines the projection point B.

Equal Area

In the Equal Area method, the bottom of the sphere rests on the projection plane. The point A on the sphere is projected down to the plane by swinging this point in an arc about the contact between the sphere and the plane, giving point B. The resultant projection is then scaled back to the size of the projection sphere.

See the Equal Angle/Equal Area Comparison topic for a comparison of plots using Equal Angle and Equal Area projection.