COURSE: DCEB 1 FT

MODULE: GEOMATICS 1

MODULE CODE: BE8101

TOPIC : BASIC PRINCIPLES

In Chapter 1, (this should be read in total) the basic principles of surveying are

discussed.

What is surveying?

Essential Activities associated with

surveying

Working from whole to part,

reconnaissance, observation &

presentation

Plane & Geodetic Surveying Whats the difference?

In plane surveying, the earth is

considered to be flat-a plane surface. In

geodetic surveying, the curvature needs

to be taken into account.

Generally, the extent of a survey will

dictate which method is required.

Branches of surveying There are many types of surveys which

are done for various purposes. It is usual

to classify them as :

Topographic surveys

Engineering surveys

Cadastral surveys

Characteristics of each classification are

given in the text.

Methods of point location Locating positions of points, features, etc

is of fundamental importance. There are 4

basic principles of point location:

Trilateration

Offsets

Traverse survey commonly used

Intersection

Reliability of a survey

All surveys must be reliable. Survey

processes must be designed in such a way

that the specifications are achieved.

The occurrence of errors-mistakes,

systematic errors, random errors must

be taken into account and check

measurements must be incorporated into

the survey process to eliminate or detect

for the presence errors. ( see page 8 )

Scale

The results of a survey are usually plotted

(shown) on plan drawing on a piece

of paper. To represent the measurements

correctly, a scale must be adopted.

Examples of typical scales used:

1: 100, 1:2000 etc.

1:1000 means 1 unit on plan represents

1000 units on ground

A distance of 1000 cm (10 m) on ground

would be represented by 1 cm on plan.

If a distance between 2 points on a line

with a scale of 1:400 was found to be

5.35 cm, what is the ground distance?

SMALL SCALE?

LARGE SCALE?