The sun., 1919-09-28


per cent of the 100000
= square miles of the United
States mapped both as to horizontal
positions of the features and the ele-
vations by contours of hills. ridges,
valleys, &C." Such is the disil!usion-
ing pronouncement Of no less an au-
thority than Col. E. Lester Jones, SUI
perintendent OF the United States
Coast and Geodetic Survey
Not only is this the general situa-
ton, but matters are really worse when
It comes to the question of details
plotted in the decades gone. AS Col.
Jones says: Some of the 40 per cent.
of the surveyed area will have to be
resurveyed because the original work
was done many years ago. when Meth
DDS were not as refined as they are to-
day and the demands of map users
were not as exact as they are at pres
ent. 1t is safe to say that not over 30
or 35 per cent, or one-third, of the
whole country is adequately mapped"
How is this situation to be met, par
ticularly il the pubic insists upon
having a correct map Of the entire ma
ton in the course Of q comparatively
short while? Precious few Persons be-
vond those directly concerned in our
efforts to span the Atlantic by aircraft
are aware Of the fact that when we
were nearly ready to start those
Nights it was suddenly discovered that
there were no accurate maps covering
the overland portion of the journey
from the aero base on Long Island to
st. Johns, Newfoundland. The inter-
vening topography was imperfectly re-
corded at various points, and it is said
that the United States and Canadian
maps did not agree owing to overlaps,
gaps and offsets which developed when
the different maps were brought to-
gether for the purpose of coordina-
ton.
The Airman's Need of Maps.
This state Of affairs is not an un-
common one over wide areas of the
United States, and the condition is cal
culated to give food for Serious thought
in view Of the rapidly growing services
Of the flying machine. Aerial craft
their correct navigation, and the fun
damental aid to this end must inevita-
bly, be accurate maps of the terrain
over which they fly. Curiously, air.
craft already have demonstrated how
they may be instrumental in the pro-
duction of these navigational guides
and at the same time contribute help
fully in the preparation of charts and
maps both for the mariner and for
many Of mans activities upon terra
f1rma- This is one of the beneficial
outcomes of the war.
During the years OF the world war
aerophotography grew steadily in I'm
portance end finally reached a point
where battery commanders would have
been quite at loss to pick out the
essential detectives for their gunfire,
to detect the changing entertainments
OF the foe and to record other data OF
military importance but for the pic
lures taken by courageous camera
men from points aloft and directly
over the theatre Of operations domi-
mated by the hostile forces. Thanks
to the skill and resehrch of photo
graphic engineers, apparatus was
evolved under Che pressure of conflict
which was virtually unthought of prior
to August of 1914. The camera for
war service made 1t possible from a
height of 1000 feet to make birdseye
views full of an amazing wealth OF
details. The procedure was not lack
ing in thrills.
Work Done Under Fire.
In order to insure the coordination
of the various plates or their prints
ii was necessary that the relatively
slow moving aeroplane should be held
at a uniform elevation and as nearly
as possible upon an even keel so that
the lens of the camera should be con-
tinually vertical. The elevation was
checked by the altitude metre, but
the maintenance of an even keel wher
lodging anti-aircraft fire was by nc
means so easy. However, the men in
this department of military operations
proved their experiences upon thou
sands of occasions, and from the pic
lures made by one or more of the OBJ
serving machines 1t was practicable
to piece together cameo print" that
would give a pretty exact view of the
foes defences and of their relations
to well known Typographical features
the latter serving as station points
or guides in establishing distances
and directions.
One does not have to be technically
minded to appreciate that wartime
aerophotography may be adapted tc
the needs OF everyday service, but II
takes an expert like Col. e. Lester
Jones to suggest how this can be done
and at the same time to reveal the
present limitations of this new born
aid to surveying. As this authority
has made plain, nearly two thirds OF
the length and breadth OF our land is