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PRACTICAL WORK №1
INTRODUCTION TO TOPOGRAPHIC MAPS

PURPOSE

The objective of this work is to learn about topographic maps and how they
are used. Topographic maps are used by a variety of different people (e.g.
engineers, planners, soldiers, geologists, and hikers) who need accurate and
detailed information about the landscape and geographic features of a region.

TOPOGRAPHIC MAP
Topographic maps are detailed, accurate graphic representations of features
that appear on the Earth’s surface. The level of detail shown on a map depends on
the scale of the map; small scale maps are less detailed than larger scale maps.

MAP PROJECTIONS
A map projection enables the curved mathematical surface approximating
the Earth to be represented on a flat sheet of paper (i.e. a map). Many projections
can be defined in terms of a particular geodetic datum.

The projection process results in the map’s spatial representation being
distorted. Imagine stretching and tearing a basketball to make its curved surface
lie flat on the ground. The magnitude of the distortion can be calculated, allowing
corrections to be made when necessary.

There are many different types of projection, each having its own advantages
and disadvantages. No projection is perfect. The projection chosen for a map will
have minimal, or acceptable, distortion relative to the map’s scale and purpose.

Fig. 1.1 Four categories of map projections

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