flatness
Sign in to savethumb|right|200px |A circle of radius compressed to an ellipse. thumb|right|200px |A sphere of radius compressed to an oblate ellipsoid of revolution.
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4 sectionsContents
- Definitions
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- See also
- References
thumb|right|200px |A circle of radius compressed to an ellipse. thumb|right|200px |A sphere of radius compressed to an oblate ellipsoid of revolution.
Flattening is a measure of the compression of a circle or sphere along a diameter to form an ellipse or an ellipsoid of revolution (spheroid) respectively. Other terms used are ellipticity, or oblateness. The usual notation for flattening is f and its definition in terms of the semi-axes a and b of the resulting ellipse or ellipsoid is f =\frac {a - b}{a}. The compression factor is b/a in each case; for the ellipse, this is also its aspect ratio.