Types of method of plotting in surveying

UPENDRA KUMAR

Types of the method in survey plotting

INTRODUCTION:- Plotting work is most important after field survey work. It has office work of a
surveyor. The main aim of plotting is the preparation of plans and sections according to field survey

notes. The plotting is completed by the surveyor or his jurisdiction. All types of surveying finished
after plotting complete.

The following points kept into the mind during plotting.

1. Left the margin about 2 cm all over the drawing sheet.
2. Choose a suitable scale on which scale covers the whole surveyed area.
3. Write the title block in the right-hand bottom corner.
4. A north line is also shown in the upper right corner.
5. The main station, subsidiary station, chain line should be shown as per standard symbols.
6. The conventional symbol used in the preparation of a map should be shown on the right-hand side.
7. The scale of the map drawn below the heading of the map

METHODS OF PLOTTING A TRAVERSE SURVEY

1. PLOTTING BY PARALLEL MERIDIANS THROUGH EACH STATION:- In this method the
the bearing of the lines drawn by the parallel method and the length of the lines drawn on suitable
scale.

 LINE BEARING LENGTH AB 140°12’ 76.80 BC 36°24’ 195.60 CD 338°24’ 37.20 DA 228°45’ 201.96

In the above table, the bearing and length of the lines are given. For drawing the traverse first draw a north-south line. Keep the protector on the line like 0 ° and 180° of the protector coincide with the north-south line of paper. From point A read the angle 140°12’ in the clockwise direction. Point the reading with a pencil and draw the line AB 76.80 on a suitable scale.

Now draw the north-south line at point B with the  SET SQUARE  by the parallel method and draw a line BC mention upper method. Complete traverse draw CD and DA by the mentioned upper method.

2.PLOTTING BY INCLUDED ANGLE METHOD:-

In this method, the north-south line is drawn on point A, and the bearing and length of AB drawn with the help of protector and scale. At a point, B keeps the protector and marks the point of the included angle between AB and BC and the length of BC is drawn on a suitable scale. Repeat the process and draw the line CD and DA.

1. BY PAPER PROTECTOR METHOD:- In this method, the traverse is drawn with the use of a large protector. The bearing of the line is drawn a central meridian from the center of the paper and protector. The length of the lines is drawn with the help of a scale ruler.

1. BY RECTANGULAR COORDINATES METHOD

 POINT TOTAL LATITUDE TOTAL DEPARTURE A 0 0 B -59.00 49.16 C 98.43 165.23 D 133.01 151.54 A 0 0

In the above table, coordinates are given of the points ABCD.In figure, X and Y axis are two lines where X represents departure and Y represents latitude and origin point A. The coordinates of the origin point 0,0.

For drawing point B whose coordinates are (-59.00,49.16). The latitude of point B is -59.00 then it shows the latitude is the negative direction or southing direction and departure is positive or east direction. Place the single set square coinciding the line AYY, and point the length 59.00 in a negative direction. Keep the other set square right angle to AYY’ and measure the length 49.16 mt in the X direction on a suitable scale point the B.Join the line AB. Repeat the process and mark points C and D . Join the line BC, CD, and DA and complete the traverse.

The rectangular coordinates method is the most accurate method of drawing

The failure to close a traverse is called a closing error. If the closing error is large, it indicates that an error has been made in chaining, and the line required to be reassured. If it is small, it may be eliminated, and the traverse is made to close by slightly modifying the shape of the polygon. The closing error is distributed among the station of the traverse by shifting each station by an amount proportional to the total distance of that station from the starting point of the traverse, and parallel to the direction of closing error.