Page 11 - December 2019

Two types of aerial photos were taken – vertical,
Mapping the Canadian North – Post WWII
By Neil Taylor
Prior to the Second World War, one of the principal
responsibilities of the Canadian Air Force was aerial
photography. It was a slow process, given the aircraft
and camera equipment of the times, and during the
entire period from 1921 to 1939 only 868,600 square
miles of territory were covered. With the advent of the
war, domestic aerial photography for mapping purposes
was discontinued.
As the war wound down, the RCAF moved to re-
implement its aerial mapping program, paying particular
attention to the Canadian North where accurate
mapping was almost nonexistent. Three B-25 Mitchell
light bombers were purchased and retrofitted with
special cameras developed by the National Research
Council for use in the development of Topographic Air
Navigation Charts.
These Mitchells were based at No. 22 Photo Wing,
Rockcliffe, Ontario, which consisted of 413 and 414
Squadrons with three Spitfires, a Hurricane, five Ansons, information on northern operations.
a Canso and a Norseman assigned to photographic and
supply operations. After some initial experimentation, a
new mapping program officially got underway in 1945.
413 Squadron B-25 Mitchell (courtesy Ron Dupas,
1000aircraftphotos.com)
employing a single directly downward looking
camera, and trimet, utilizing a combination of three
cameras – one pointed vertically downward and the
other two mounted obliquely pointed in directions
perpendicular to the direction of flight. The trimet
system, through simultaneous exposures, enabled
photographs from horizon to horizon of narrow
strips of ground. This enabled the coverage from a
single flight line to be greatly expanded, thus
requiring fewer flight lines when photographing vast
expanses of territory.
The season for aerial photography in the Canadian
North was short since ground needed to be free of
ice and snow, and it could be further hampered by
cloud cover and smoke from forest fires. The small
airplanes were unable to cover much territory so in
1946 the Ansons were phased out and the Mitchells
along with a few Lancasters assumed the lion’s share
of the work.
That same year, a very controversial program of the
United States Army Air Forces, called Operation
Polaris, began in the Canadian Arctic. It involved
three round trips per week between Meeks Field,
Iceland and Ladd Field, Alaska for the purpose of
improving air force operational capabilities in the far
north, the likely battleground in the event of a Soviet
air strike on North America. Flying in the Arctic was
difficult due to adverse weather conditions,
unreliable magnetic compasses and the lack of
accurate mapping. Through these regular transport
flights, the United States hoped to gain valuable
The Government of Canada granted approval for the
transport flights in 1946, but the following year it
learned that the Americans were surreptitiously
taking aerial photographs during these flights. The
Canadians feared the Americans were searching for
undiscovered islands that they could claim for their
own thus undermining Canadian sovereignty in the
north. Diplomatic objections were filed and
eventually the Americans admitted to the illicit aerial
photography and agreed to suspend all such
activities.