PLANE TABLE SURVEYING
Introduction
A plane table surveying is a graphical method of surveying. In this method of surveying, field
observation and plotting are done simultaneously helping the surveyor to compare the plotted
details with actual features of the ground.
Advantages of Plane Table Survey
It is suitable for location of details as well as contouring for large scale maps directly in
the field.
As surveying and plotting are done simultaneously in the field, chances of getting
omission of any detail get less.
The plotting details can immediately get compared with the actual objects present in the
field. Thus errors as well as accuracy of the plot can be ascertained as the work
progresses in the field.
Contours and specific features can be represented and checked conveniently as the whole
area is in view at the time of plotting.
Only relevant details are located because the map is drawn as the survey progresses.
Irrelevant details get omitted in the field itself.
The plane table survey is generally more rapid and less costly than most other types of
survey.
As the instruments used are simple, not much skill for operation of instruments is
required. This method of survey requires no field book.
Disadvantages of Plane Table Survey
The plane table survey is not possible in unfavorable climates such as rain, fog etc.
This method of survey is not very accurate and thus unsuitable for large scale or precise
work.
As no field book is maintained, plotting at different scale require full exercise.
The method requires large amount of time to be spent in the field.
Quality of the final map depends largely on the drafting capability of the surveyor.
This method is effective in relatively open country where stations can be sighted easily.
Instruments
A plane table mounted on a tripod stand and a number of accessories are used during plane table
survey. The accessories consist of alidade, spirit level, trough compass, plumbing fork, plumb
bob, drawing sheet.