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Mollweide Projection


MollweideProjection

The Mollweide projection is a map projection also called the elliptical projection or homolographic equal-area projection. The forward transformation is

x=(2sqrt(2)(lambda-lambda_0)costheta)/pi
(1)
y=sqrt(2)sintheta,
(2)

where theta is given by

 2theta+sin(2theta)=pisinphi.
(3)

Newton's method can then be used to compute theta^' iteratively from

 Deltatheta^'=-(theta^'+sintheta^'-pisinphi)/(1+costheta^'),
(4)

where

 theta=1/2theta^'
(5)

(Snyder 1987, p. 251) or, better yet,

 theta^'=2sin^(-1)((2phi)/pi)
(6)

can be used as a first guess.

The inverse formulas are

phi=sin^(-1)[(2theta+sin(2theta))/pi]
(7)
lambda=lambda_0+(pix)/(2sqrt(2)costheta),
(8)

where

 theta=sin^(-1)(y/(sqrt(2))).
(9)

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References

Snyder, J. P. Map Projections--A Working Manual. U. S. Geological Survey Professional Paper 1395. Washington, DC: U. S. Government Printing Office, pp. 249-252, 1987.

Referenced on Wolfram|Alpha

Mollweide Projection

Cite this as:

Weisstein, Eric W. "Mollweide Projection." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/MollweideProjection.html

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