The AuthaGraph map is an equal area map, not a conformal map, so its local maps are distorted. For example, you can see that the meridians and parallels fail t

The AuthaGraph map is an equal area map, not a conformal map, so its local maps are distorted. For example, you can see that the meridians and parallels fail to meet at right angles. The similar Lee Conformal Tetrahedric projection (http://www.csiss.org/map-projections/Miscellaneous/Lee_Conformal_Tetrahedric.pdf http://www.csiss.org/map-projections/Miscellaneous/Lee_Confo...) has undistorted local maps, at the expense of somewhat large area differences for different regions (though perhaps not as bad as Mercator).