Evening star., 1944-04-23
npleting the Largest Mapping Job in History

tier and possible postwar bonanza Of
untold mineral resources, is beginning
to yield up some of Its enigmatic secrets
to the modern flying mapmakers Of
the Army Air Forces and the Geological
Survey, according to a report today to
Secretary of the Interior Harold L.
Ickes by William Embry Wrather, di-
rector of the survey.
Vast stretches of Arctic Alaskan terri
tory, much of it hitherto unobserved
by the human eye since the beginning
of time, soon will be revealed on a
map showing topographic data similar
to those published of Virginia or Texas,
but in smaller scale, the report states.
1t will show rivers that have been
meandering toward the Arctic Ocean for
untold centuries without ever having
been christened with names.
1t will reveal typographical features
Of possible sites for modern airports,
when that part of the world becomes
the logical air route between the United
States and Moscow or Asia.
It will disclose apparent tundra-cov-
cred wastes that may provide tipoff
on future treasure to the trained eyes
of tomorrow's prospectors. )
Largest Area Ever Mapped
The Northern Alaska mapping job,
now nearing completion, constitutes the
largest area ever mapped and fixed in
geographic position as single unit. 1t
is part of the joint Photographic Tri-
Metrogon aerial mapping program of
the Army Air Forces and the Geological
Survey which was initiated in 1941.
Since then this modern counterpart
of the Lewis and Clark Expedition has
mapped over 100000 square miles of
the earth's surface in various parts of
the world for war purposes. But in
stead of trudging laboriously through
primeval forests and over desert wastes,
these present-day aerial mapmakers
have done their field work by thunder
ing over their mapping objectives in
Flying Fortresses and Liberator bomb
ers, each one of which is capable of
photographing 10000 square miles of
terrain in three hours.
New Unmapped Territory
The Northern Alaska map covers ap-
proximately $4,000 square miles of ter
ritory, four-f1fths of which previously
had been virtually unmapped. This is
as much as the combined areas of all
the New England States of Maine, New
Hampshire, Vermont, Massachusetts,
Connecticut and Rhode Island plus New
York, New Jersey, Pennsylvania, Mary
land, Delaware, Virginia, West Virginia
and Tennessee. It includes the area ex-
tending from the mouth of the Macken-
z1e River, in Canada, westward to the
Arctic waters separating Alaska and ST.
IBERIA, southwark to Fairbanks and
northward to Point Barrow.
To provide the surveys mapmaking
experts with the necessary raw mate
rials" the Army Air Force flyers, using
planes specially equipped with Tri-
Metrogon cameras, took approximately
25,000 photographs from over 5000 ex-
posture stations. Laid edge to edge, the
themselves would extend
over quarter of an acre of ground.
The map, Mr.. Wrather reported, has
Just passed the '1aydown" stage, which
means that the key points shown on the
photographs have been transferred in
proper geographic relationship by means
OF series of intricate calculations with
mechanical appliances to a cellulose
acetate base. To this base the delinea-
tions OF streams, Typographical and
cultural features of Landscape are trans
ferred and the names of known places
added.
Fixed on Templates
The Photographic points are fixed on
the acetate base by use of metal tenn
plates~% which to the layman resemble
structural metal toys familiar in many
homes at Christmas time. These tenn
plates are used to obtain a mechanical
simultaneous adjustment of the key
points in the whole unit area SO they
Will be in proper relationship to the few
points of known latitude and, longitude
which fix the lay-down.
Tri-Metrogon mapping from aerial
photographs is highly intricate and
scientific process. 1t provides maps of
adequate detail with many times the
speed required by previously available
methods. While the old and slower
method can provide a greater amount
OF detail, the Tri-Metrogon system af-
fords many advantages.
A Painstakins Task
From taking the original photographs
to the final product there are several
stages, each requiring the most. exacting
and painstaking application of scientific
instruments in the hands of experienced
technicians. Some of these instruments
have had to be originated and devel-
oped by scientists of the Geological Sur
vey and the AAF before the lob could
be done.
The photographs for mapping pur-
poses are taken with three wide-angle
cameras mounted in a plane SO that
three simultaneous exposures on 9xe-
inch negatives can be snapped covering
an area from one horizon to the other.
Ine central camera is pointed vertically
downward and the two others are
pointed obliquely right and left so that