d3/d3-plugins — pull request #54 by jasondavies (2013-03-04 13:45:28+00:00)
Title: Add auxiliary stream transformation.

This allows the spherical form of a map projection to be adapted for use
with the ellipsoid by substitution of an “auxiliary” latitude in place
of the geographic latitude. The geographic latitude normally refers to
the angle a line perpendicular to the surface of the ellipsoid at a
particular point makes with the equatorial plane. Auxiliary latitudes
transform the ellipsoid to a sphere under restraints such as
conformality or equal area (authalic).