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positive and negative signs are used to identify locations. For
example, the geographic coordinate of Vilnius in degrees minutes and
seconds (DMS) is: 25 16’ 00’’ W and 54 41’ 00’’ N. In decimal
degrees (DD) it is: +25.276 and 54.689.

VI. INDIVIDUAL WORK

Task 1. Read the article and match the headline with the
appropriate paragraph.

a) The Indian Datum

b) The European Datum
c) Great Britain 1936 Datum
d) Takyo Datum

e) The North American Datum 1927

Preferred Datums

In areas of overlapping geodetic triangulation networks, each
computed on a different datum, the coordinates of the points given
with respect to one datum will differ from those given with respect to

the other. The differences can be used to derive transformation
formulas. Datums are connected by developing transformation
formulas at common points, either between overlapping control
networks or by satellite connections.

Many countries have developed national datums which differ
from those of their neighbors. Accordingly, national maps and charts
often do not agree along national borders.

1. ___ has been used in the United States for about 60 years, but it
is being replaced by datums based on the World Geodetic System.
NAD 27 coordinates are based on the latitude and longitude of a
triangulation station at Mead’s Ranch in Kansas, the azimuth to a

nearby triangulation station called Waldo, and the mathematical
parameters of the Clarke Ellipsoid of 1866. Other datums throughout
the world use different assumptions as to origin points and ellipsoids.

2. The origin of ___ is at Potsdam, Germany. Numerous national
systems have been joined into a large datum based upon the
International Ellipsoid of 1924 which was oriented by a modified

astrogeodetic method. European, African, and Asian triangulation
chains were connected, and African measurements from Cairo to Cape
Town were completed. Thus, all of Europe, Africa, and Asia are

molded into one great system. Through common survey stations, it
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