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accurate levels and with a more rigorous
observing procedure than general
engineering levelling.
2. A level surface b) is established by giving a benchmark an

assumed value (e.g. 100.000 m) to which all
levels in the local area will be reduced.

3. A level datum c) is a device used in surveying and related
disciplines to provide a solid and level
surface on which to make field drawings,
charts and maps.

4. Height of d) is applied to any method of measuring
Collimation directly with a graduated staff the difference
in elevation between two or more points.

5. A bench mark e) is a surface which is everywhere
(BM) perpendicular to the direction of the force of
gravity.

6. Precise levelling f) is an arbitrary level surface to which
elevations are referred.
7. A plane table g) is the term given to a definite, permanent

accessible point of known height above a
datum to which the height of other points
can be referred.

8. Graphometer or h) is the elevation of the optical axis of the
semicircle telescope at the time of the setup. The line
of collimation is the imaginary line at the

elevation.
9. An assumed i) is an electronic/optical instrument used in
datum modern surveying and building
construction.

10. A total station j) is a surveying instrument used for angle
measurements. It consists of a semicircular

limb divided into 180 degrees and
sometimes subdivided into minutes.

III. GRAMMAR REVIEW

Task 1. Match the words in A with the opposites in B. Build
up 5 sentences using them.

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