Welcome to this blog, Today I will discuss plane table surveying and its methods. So guys are ready to get one of the best knowledge of this topic. Do you know what is plane table survey?
What is Plane Table Surveying?
Surveying instrument survey is to finish making small map or drawing. during this survey can cover small areas thanks to its surveying instrument size. This survey is extremely tedious for the plotted big scale map. during this survey time consumption is low. And the field observation and plotting were completed at the same time.
Principle of Plane Table Surveying
The main Principle of Plane Table Surveying is dependent on parallelism.
According to the parallelism, All the rays drawn through the various details should pass through the survey station.
The position of the plane table is kept identical in each of the stations. This is done by orienting the plane table in the direction of magnetic north in each station on the ground.
The objective of Plane Table Surveying
The followings are the objective of the plane table surveying:
- To prepare the small-scale maps.
- To mention the small area topographic details on the field.
- To carry out small-scale ground details.
- This survey is done where the compass survey is not possible.
- To minimize the time-consuming.
- To increase the precision of the surveying in the field.
Plane Table Surveying Instruments
The plane table is that the small drafting board is mounted on a light tripod in such how that they rotate about a vertical axis and clamped be any position. The paper was restored to the plan table.
It is a wooden or brass ruler about 50-60cm long. it’s also called a sight ruler. it’s been two types:
Plain alidade: it’s a metal or wooden ruler about 50 cm. sight vans provided with a fiducial edge. It is an important instrument for the plane table survey.
Telescope alidade: It contains a telescope for sighting. it no provides a sight van.
It is the metal strip bent within the slope of u ‘U’ that has an equal arm of length. the highest arm a point and the bottom arm carries a hook for suspended plumb. This use for centering the table over the station.
It is a tiny metal tube containing a small bubble of spirit. The bubble is visible for the highest graduated glass tube. Specially use for leveling of a surveying instrument.
Compass is an instrument, which used for determining the north line direction. A special magnet is used within the compass. So, it’s called a compass. Without a compass, a plantable can be impossible.
Temporary adjustment of Plane Table Survey
The main function of a plantable survey is a temporary adjustment. The starting phase of the surveying instrument survey is an adjustment. Data often observe with accurate adjustment. The following three methods are for Temporary adjustment for every station in surveying instrument survey:
Centering: After fixing the paper on the surveying instrument an appropriate point is chosen on the sheet to represent the bottom point with the assistance of a plumbing fork. The vertically drop plumbing fork is accurate to measure the middle of a ground point.
Leveling: leveling the extended by placing the level spirit level at the various corners and various positions on the table. The bubble is delivered to the middle of its run at every position of the table by adjusting the leg. The spirit bubble should horizontally fix on the table.
Orientation: when the surveying instrument survey is conducted by connecting the stations, the orientation must perform at every successive station, orientation often do by using through compass and back sighting. For the gathering ground point, orientation is the important part. the rear sight orientates and foresight orientate is most.
Methods of surveying of Plane Table Survey
Followings are the tactic of a surveying instrument survey
This method is suitable for locating the thing from the only station. during this method rays were drawn from the station to the objects and distance was measured and plotted suitable scale.
This method is suitable for locating inaccessible points by the intersection of rays from the instrument station. The intersection method employs when the inaccessible point is visible from the instrument station but the linear distance is way from the station.
This method is suitable for connecting the traverse station to every other. This method is analogous to compass and Theodolite traverse. Field observation and plotting are complete simultaneously with the assistance of the radiation and intersection method.
Advantages of Plane Table Surveying
Followings are the Advantages of Plane Table Survey
Plane Table surveying is a very quick and easy type of surveing.
Office work is totally eliminated in plane table surveying.
For plane table surveying not requires skill and experience to prepare a map.
For small area can be included in this surveying.
If the area is magnetic but the compass surveying is not possible then this survey is done.
The survey provides accurate contour and irregular objects on the ground.
The cost of this surveying is very cheap than other types of surveying.
In-plane table The errors of the field book are eliminated.
The map is prepared on the field.
Disadvantages of plane Table Surveying
Plane Table is not suitable for large area.
This type of survey is extremely affected by climate conditions. It cannot possible to carry out in monsoon or highly winded season.
In this survey, the instrument is set up at each station on the ground.
Plane Table survey is not suitable in foggy areas due to the lack of visibility of the ground objects.
Using instruments are very heavy so that the instrument is not handeling propely, it is so hard to handle due to heavy.
This survey is very hard to re-prepare the map in different scale.
This is the Plane Table Survey information. All about this information is very helpful to you. I hope this article is very helpful to you. if you like please share with other friends.Thanks for viewing my site. If you’ve got any doubt please contact me.