Map Projections: Classic Interrupted Maps

Map Projections

Classic Interrupted Maps

Interrupted Mollweide Map

Interrupted Mollweide hemispheres, central meridians 110°W and 70°E

Pseudocylindrical projections are especially appropriate for linear interruptions along meridians, like in this divided Mollweide map: meridians are still mapped to elliptical arcs, and those at (after any oblique rotation) 90°W and 90°E are circular. This interrupted form with symmetrical central meridians comprises two perfect circles. Compare the azimuthal orthographic and stereographic maps of exactly the same regions.

Interrupted Mollweide map, simplified lobes

In 1916, before designing his most famous projection, J.P. Goode experimented interrupting a pure Mollweide projection. In an arrangement slightly more complex than that shown here, the result was popular but eventually superseded by the true homolosine projection.

Interrupted Goode Homolosine Projection

Interrupted Goode homolosine map; Iceland and portions of Greenland and Eastern Asia appear twice.

This is a common form of J.P. Goode's homolosine projection, easily recognized due to its broken meridians. The lobe arrangement shown here is similar to that originally published by Goode (1923-1925). Some maps of this kind include extensions repeating a few portions in order to show Greenland and eastern Russia uninterrupted.

Interrupted Boggs Eumorphic

Interrupted eumorphic map with extensions repeating Greenland and the Behring sea region. The break in Eurasian meridians is clearly visible.

Boggs preferred his hybrid eumorphic projection in an interrupted form resembling Goode's homolosine maps. Since it averages the sinusoidal and Mollweide projections instead of joining bands projected separately, meridians in an eumorphic map are unbroken except (arbitrarily) at the Eurasian lobe: Boggs usually employed a different central meridian north of the 40°N parallel.