SHORAN OPERATIONS IN CANADA
J. E. R. ROSS
Dominion Geodesist
Department of Mines and Technical Surveys, Ottawa
Canadian operations in shoran in application to surveying and mapping may
be regarded as having been initiated in 1947. During the succeeding two winters
experiments were made in the vicinity of Ottawa to assess the accuracy of shoran
positioning in comparison with that obtained by first-order triangulation. The
results were encouraging enough to warrant consideration of shoran as a means of
establishing position in Canada’s vast northland. It had to be first demonstrated
that a shoran net of considerable length, starting at a base derived from the first-
order triangulation, could give an acceptable closure when carried over the inter
vening distance to another geodetic base. In 1949 and 1950 such a shoran net
of 1100 miles axial length between geodetic bases was completed in Manitoba
and Saskatchewan with results which indicated that shoran, with careful super
vision of all details, could produce results of accuracy superior to astronomic
positioning, which is the only reasonable alternative method of control at the
present stage of development of the northern areas. Over 800 geographic posi
tions have been determined in the last ten years by the exploratory astronomic
method, and these have been satisfactory for control in the production of small-
scale maps where displacements of up to 400 feet are not plottable. Such astron
omic determinations are not sufficiently accurate control for the large-scale
mapping which is essential and in demand now by the various agencies concerned
in the development of oil and ore potentials, not only in local and relatively small
areas but in regions of vast extent.
In the seasons of 1949-50-51 the shoran net has been advanced from the
49th parallel in southern Manitoba, northwesterly through the provinces of Mani
toba, Saskatchewan, and northward down the Mackenzie River basin to the Arctic
coast in latitude 70°, over an axial length of 2,500 miles. In this net 40 shoran
stations have been established and the 149 lines between stations, averaging 210
miles in length and forming the geometrical pattern of the net, have each been
measured 16 times. In addition, 13 stations have been prepared in a 1,200-mile
belt stretching from Great Bear Lake eastward to Hudson Strait. These 13
stations form the basis of a shoran net of 46 lines which will be measured in 1952.
Precise Control in Northern Areas
The existing precise triangulation control is largely confined to the settled
area which stretches from coast to coast along the southern part of Canada.
There is also a continuous arc of triangulation along the Pacific coast to Skagway,
thence to Whitehorse, Y.T., and thence westerly astride the Alaska Highway to the
141st meridian and also easterly to the vicinity of Fort Nelson, in the northeast
part of British Columbia. In addition, minor triangulation control exists along
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