Hammer Projection - Development

Development

Directly inspired by the Aitoff projection, Hammer suggested the use of the equatorial form of the Lambert azimuthal equal-area projection instead of Aitoff's use of the azimuthal equidistant projection:

where and are the x and y components of the equatorial Lambert azimuthal equal-area projection. Written out explicitly:

The inverse is calculated with the intermediate variable

The longitude and latitudes can then be calculated by


\begin{align}
\lambda &= 2 \arctan \left \\
\phi &= \arcsin(zy)
\end{align}

where is the longitude from the central meridian and is the latitude.

Visually, the Aitoff and Hammer projections are very similar. The Hammer has seen more use because of its equal-area property. The Mollweide projection is another equal-area projection of similar aspect, though with straight parallels of latitude, unlike the Hammer's curved parallels.

Read more about this topic:  Hammer Projection

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