Plane table surveying is a graphical surveying method where observations and plotting are done simultaneously. It uses a plane table with an alidade and other instruments to take sightings of objects from multiple reference points and plot their positions by triangulating the lines of sight on the drawing sheet. This allows quick plotting of surface details. Advantages are that it is fast and mistakes are less likely, while disadvantages are that it is not suitable for large areas or wet weather. Common methods used are radiation, intersection, traverse and resection.

1. Surveying Practical
Plane Table Surveying

2. Plane Table Surveying 2
Plane Table Surveying:
•It is a graphical method of surveying
•Observations and plotting are done simultaneously
•Suitable for plotting surface details like buildings, trees,
or other permanent objects.
Advantages:
•Quick and low-cost
•Less mistakes  observations & plotting done simultaneously
Disadvantages:
•Not suitable for wet weather or large area.
Introduction

3. Plane Table Surveying 3
Plane Table
Instruments

4. Plane Table Surveying 4
•Plane Table with Tripod
•Alidade (for sighting)
•Plumbing fork with plumb bob (for centering)
•Spirit level (for leveling)
•Compass (for orientation)
•Ranging rod (for location)
•Drawing paper, pencil, etc.
Instruments

5. Plane Table Surveying 5
Plane Alidade
Instruments, cont’d
Plumbing fork

6. Plane Table Surveying 6
Methods of Plane Tabling
3. Traverse
1. Radiation 2. Intersection
4. Resection

7. Plane Table Surveying 7
Main operations are: 1. Fixing, 2. Setting, 3. Sighting
1. Fixing the Table
Fix the table to the tripod. Select & mark two
reference stations (say “A” and “B”) on the ground.
2. Setting (Centering, Leveling and Orienting)
Centering  set the plane table on the first point
(say, point “A”) so that its plotted position is exactly
over the position on the ground by moving the legs of
the tripod and using the plumbing fork and plumb bob.
Leveling  ensure the level of the plane table at two
positions of spirit level, right angles to each other.
Working Operations

8. Plane Table Surveying 8
Orienting  We’ll use the “back sighting” method.
Set the plane table at station “A” so that any line to be
plotted is parallel to corresponding lines on the ground.
After completing sightings of all permanent objects
from station “A”, draw a line (name it as “Ray AB”) from
“A” towards the 2nd station “B”.
Now measure the actual distance of AB on ground
and scale down to plot position of station “B”.
Then shift the table to station “B”, center, and level.
See a ranging rod erected at station “A” through the
alidade and match BA with Ray AB.
Clamp table at station “B”.
Working Operations, cont’d

9. Plane Table Surveying 9
3. Sighting: Use Intersection Method
Using Alidade, draw rays to the objects from two
stations - “A” and “B”
On paper, fix a object’s position at point of intersection
of two rays drawn from “A” and “B” towards it.
Working Operations, cont’d