Transverse survey
E
Transverse or offset surveys are
used to find the area of irregular
A
shapes, such as the field ABCDE to
the right.
In this method the surveyor:
•walks along a straight line (eg AD),
B
C
•the transverse line,
•often a diagonal of the area to be surveyed,
•measuring distances along this line and
•distances to major features, or offsets, when they are at RIGHT
ANGLES to the transverse line.
•For example…
D
Transverse survey
To survey the field ABCDE:
1. Choose any suitable diagonal,
ie AD
2. Measure the lengths along the
transverse line, ie AP, PQ, QR
and RD.
3. Measure the lengths of the
offsets, ie BQ, CR and EP.
Field diagrams
When in the field doing the survey
the surveyor sketches the
information as a field diagram.
To complete a field diagram:
1. Start at one end of the
transverse line
2. Write down the cumulative
distances of the offsets from the
starting point
3. Write down the lengths of the
offsets, on the left or right, as
appropriate.
4. Units are not shown.
20+27=47
Example 1
a) Complete a field diagram for this field
J
40
K 28 30
22 15 I
L 20 14
H




b) Calculate the area of this field.
A1 = ½bh
A3 = ½ × 28 × 10ATOT = 140+384+140+300
= 140
= 964u2
= ½ × 20 × 14
= 140
A2 = ½(a + b)h
A4 = ½ × 40 × 15
= ½ × (20 + 28) × 16 = 300
= 384
Example 2
D
94
Sketch the field represented by this field diagram.
79 39 C
D
47 35 B
E 29 27
15
39
A
C
You may also be asked to:
32
1. Make a scale drawing of
the field
35
B
2. Find lengths such as AB
29
20
E
or BC.
27
A
Today’s work
Field Diagrams Worksheet
#1, 2, 3, 4
Field Diagram Task





On the oval there are two‘irregular fields’ marked
with different coloured cones.
Use the trundle wheels/tape measures and set
squares to measure the offsets for the two
irregular fields.
Create a notebook entry for the two irregular
fields.
Sketch the two fields, showing all the appropriate
measurements.
Calculate the area & perimeter of both fields.