Waldo R. Tobler’s family of hyperelliptical projections is available for d3-geo-projection as pull request #133.
You can try the following parameters:
Default:
d3.geoHyperelliptical().alpha(0).gamma(1.183136).k(2.5)
(fig. 9)Values described in Tobler, “The Hyperelliptical and Other New Pseudo Cylindrical Equal Area Map Projections”, Journal of Geophysical Research, 1973:
d3.geoHyperelliptical().alpha(0).gamma(6).k(1/2)
(fig. 5)d3.geoHyperelliptical().alpha(1/4).gamma(1.194).k(2)
(fig. 6)d3.geoHyperelliptical().alpha(1/2).gamma(Math.PI/2).k(2)
(fig. 7)d3.geoHyperelliptical().alpha(0).gamma(1.461).k(3/2)
(fig. 8)