Tobler hyperelliptical projection

The Tobler hyperelliptical projection is a family of pseudocylindrical projections used for mapping the earth.

It is named for Waldo R. Tobler, its inventor.

It is an equal-area projection. In the normal aspect, the parallels of latitude are parallel straight lines whose spacing is calculated to provide the equal-area property; the meridians of longitude (except for the central meridian, which is a straight line perpendicular to the lines representing parallels) are curves of the form a|x|^γ + b|y|^γ = 1 (with a dependent on longitude and b constant for a given map), known as superellipses or Lamé curves. When γ = 2 the projection becomes the Mollweide projection; when γ=1 it becomes the Collignon projection; the limiting case as γ→infinity is the Cylindrical equal-area projection (Lambert cylindrical equal-area, Gall–Peters, or Behrmann projection). Values of γ that are favored by Tobler and others are generally greater than 2.

The projection was first described by Tobler in 1973.