flattening

(1) A mathematical expression of the relative lengths of the major and minor axes of an ellipsoid: f= (a - b)/a), where "a" is the length of the major axis and "b" is the length of the minor axis.

(2) A measure of the flattening of an ellipse. A circle has a flattening of 0. Flattening of the WGS-84 ellipsoid is approximately 1/298.257223563 = 0.00335281066474.

Flattening is usually displayed as its inverse value (for example, 298.257223563 instead of 0.00335281066474) for easier reading.