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The surveyor, using temporary/permanent markers, places several points in the
ground. These points, called stations, are arranged throughout the site area under
study so that it can be easily seen.
The relative horizontal positions of these points are established, usually with a
very high degree of precisions and accuracy; this is done using transverse,
triangulation or trilateration methods.
2. Vertical control survey
The elevations of relatively permanent reference points are determined by
precise leveling methods. Marked points of known elevations are called elevation
benchmarks. The network of stations and benchmarks provide a framework for
horizontal and vertical control, up on which less accurate surveys can be based.
 Route survey
It is performed in order to establish horizontal and vertical controls, to obtain
topographic data, and to layout the position of high ways, railroads, pipe lines etc.
The primary aspect of route surveying is that the project area is very narrow
compared with its length, which can extend for many kilometers.
 Other types of surveys
HYRDRAULIC SURVEY: is a preliminary survey applied to a natural body of
water, e.g. mapping of shorelines, harbor etc.
RECONNAISSANCE SURVEY: is a preliminary survey conducted to get
rough data regarding a tract of land.
PHOTOGRAMMETRIC SURVEYING: uses relatively accurate methods to
convert aerial photographs in to useful topographic maps.

1.5 Field Notes
All surveys must be free from mistakes or blunders. A potential source of
major mistakes in surveying practice is the careless or improper recording of field
notes. The art of eliminating blunders is one of the most important elements in
surveying practice.

RULES FOR FIELD NOTES
1. Record all field data carefully in a field book at the moment they are
determined.
2. All data should be checked at the time they are recorded.
3. An incorrect entry of measured data should be neatly lined out, the correct
number entered next to or above it.
4. Field notes should not be altered, and even data that are crossed out should
still remain legible.
5. Original field records should never be destroyed, even if they are copied for
one reason to another.

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