Plane table surveying is a graphical method of surveying in which the field work and plotting are carried out simultaneously.
Therefore it is suitable for the preparation of small scale maps or medium scale maps
In filling the details between the two stations fixed by theodolite traversing on triangulation.
Principle:
- The principle of plane table surveying is that the rays drawn from different points should pass through a single point. I.e. a position of station point.
- The position of the plane table at any station should be the same as that previous station.
Setting up of plane table:
While using plane table the following are needed:
- Fixing table
- Centering
- Leveling
- Orientation
- Sighting the objects
Methods of plane table surveying:
- Radiation
- Intersection
- Traversing
- resection
Merits:
- It is rapid and suitable for small scale maps.
- Since one carries out field work and plotting work simultaneously.
- The surveyor can compare the plotting work with the actual features of the area
- One requires no greater skill to pre[pare satisfactory map.
- It is most suitable for the areas where the comparison survey cannot be done due to local attraction.
- It is less costly
- Therefore check lines defects the errors of measurement and plotting on the field itself.
- Lastly the office work consists of only finishing drawings.
Demerits:
- Firstly it is unsuitable for work in wet climate and in high wind.
- It is inconvenient to replot the survey to different scales and to compute the quantities when proper field notes are not available.
- It is only suitable for open country.
- One does not intend for greater accuracy.
- Instrument is heavy
- Number of accessories are to be carried and losses may get lost.
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