Geoscience Reference
In-Depth Information
Figure 9.6 Robinson Projection. Compromise projection adopted by the National
Geographic Society to serve as a base map for many of their world maps, over a bounded
time period. Found originally on the link listed below. NASA, Pseudocylindrical
html
graticule as one proceeds poleward carries the map “flesh” on the “bones” of
the graticule to a more globe-like appearance.
The idea of using an underlying grid system to transform one set of masses
to another is not unique to geography or mapping. In the early part of the
twentieth century, Sir D'Arcy Wentworth Thompson (1917) employed a similar
strategy to look for mathematical characterizations that would carry one fish
species to another. The cartographer Waldo Tobler (1961a and 1961b) carried
this idea forward in the world of mapping. Indeed, Tobler's hyperelliptical is
another compromise projection (pseudocylindrical) that has the additional
characteristic of being equal-area (
http://www.csiss.org/map-projections/
Pseudocylindrical/Hyperelliptical.pdf
).
There are an infinite number of maps possible and thus an infinite number
of categorization schemes possible. There is no “best” set of categories. Some
might be more useful than others, though. Another broad type of projection
that the reader may see is “interrupted” projections. These seek to emphasize
landmasses by cutting the projection apart in the ocean. The Goode homolo-
sine, based on the sinusoidal and the Mollweide projections, is one example,
shown in
Figure 9.7.
The use of the Mollweide in latitudes closer to the poles
reduces the meridian compression evident in the sinusoidal. Others include
the Philbrick interrupted sinumollweide, also based on the sinusoidal and the
Mollweide projections (Philbrick, 1986 reprint). Abstractly, all maps are “inter-
rupted”—but when the interruption occurs along rectangular outer edges, our
rectilinearly trained minds are not jarred!
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