Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-08-25
NAVY MAP SHOWS
SHORTEST. ROUTES
Distance to Any Point on
Earth Can Be Determined
Instantly.
BY THOMAS r. HENRY.

The City of Singapore lies on top of
the Equator.
The City of Washington is approx
mately 40 degrees north of the Equator.
Naturally, to get TO Singapore from
Washington by the shortest route, one
would suppose, 1t would be common
sense to fly south. Quite to the con-
trary the shortest way to get Thereby
far--is due north and directly across
the North Pole.
The shortest route to Peiping is di-
rectly across Labrador, although the
Chinese city is on the same parallel
of latitude as Washington. An Army
officer ordered from the War Depart
ment here to duty in Manila could
save many weary miles, If adequate
transportation was available, by going
across the Arctic Ocean north of Alaska
and over the frozen wastes of Northern
Siberia.
North Cape, Australia, about IS de-
grees south of Washington, can be
reached most directly across Alaska. 40
degrees north of the National Capital
The shortest distance from Washing
ton to Bombay. 40 degrees south. is
across the southern tip of Greenland.
Even to get TO Suez, the proper direc-
ton would be northeast, skirting just
south of Paris. which is on the same
parallel Of latitude as Newfoundland.
To go south, If south happens to be
on the other side of the earth, follow
the compass north. There is nothing
metaphysical about this but merely the
geometrical axiom that the shortest dis
lance between two points on the sur
face of sphere, such as the earth, is
the arc of great circle. There can be
no straight lines on such surface and
the parallels of latitude drawn through
T0intC oil "a net INor cn
they are parallels, represent the short
est distances between the points as
would be the case If the earth were a
fiat surface.
The real situation is shown in a new
map just issued by the Navy Hydro
graphic Office by means of which the
distance from Washington to any point
on earth can be determined instantly
Any straight line drawn on this map
would become great circle on a spheri-
cal surface. This is the first time that
the great circle axiom has been pre-
sented graphically on fiat surface with
special reference to Washington and
may clear up in many minds some of
the geographical puzzles of long-dis-
lance aeriah navigation, as we'll as tbs
possible future value of the Arctic as a
southeast road when aviation has been
developed sufficiently to make use of it.
III 1ldbIcI1lIiS OuL lLit 1OE LIE
poses of this map the true mileage has
been preserved, difficult mathematical
feat. Consequently the sizes of islands
and continents appear quite different
from on the ordinary Mercator projec-
ton maps, where the ''fattening out"
process is by an Their principle. Espe-
cially striking is the small size of Europe
among the continents and the enormous
extent of Africa and Asia. 1t also shows
much more clearly than other maps the
great difference in extent between the
North Atlantic and the North Pacific.
On the Mercator projection maps,
most familiar in aliases, distances in
the Northern Hemisphere are greatly
distorted, Siberia appearing. as big as
all the rest of Asia combined and Green
land about as large as Australia. Con-
sequently straightline distances on this
map are greatly exaggerated.
Straight lines on the Mercator pro-
lection maps do not even approximate
the shortest distance between points,
except between nearby points. For the
larger areas the great circles" must be
represented by curves.
But the mathematical construction of
the present map is such that the great
circle is represented by straight line
quite accurately. So ruler laid down
connecting any two points on this map
shows the shortest way to get there.
The actual following of the route is
something else again.