Plotting procedure in surveying

 EQUIPMENTS FOR PLOTTING

1. Drawing board (normal size – 1000 mm x 700 mm)

2. Tee-square

3. Set-square (45⁰ and 60⁰)

4. Protractor

5. Cardboard scale – set of eight

6. Instrument box

7. French curve

8. Offset scale

9. Drawing paper of good quality (normal size – 880 mm x 625 mm)

10. Pencils of good quality – 2 H, 3 H or 4 H

11. Eraser (rubber) of good quality

12. Board clips or pins

13. Ink (Chinese ink or Indian ink) of required shade

14. Colour of required shade

15. Inking pen (or Hi-tech pen) and brushes

16. Handkerchief, knife, paperweight, etc.

17. Mini drafter

PROCEDURE OF PLOTTING

1. A suitable scale is chosen so that the area can be accommodated in the space available on the map.

2. A margin of about 2 cm from the edge of the sheet is drawn around the sheet.

3. The title block is prepared on the right-hand bottom corner.

4. The north line is marked on the right-hand top corner, and should preferably be vertical. When it is not convenient to have a vertical north line, it may be inclined to accommodate the whole area within the map.
5. A suitable position for the base-line is selected on the sheet so that the whole area along with all the objects it contains can be drawn within the space available in the map.

6. The framework is completed with all survey lines, check lines and tie lines. If there is some plotting error which exceeds the permissible limit, the incorrect lines should be resurveyed.

7. Until the framework is completed in proper form, the offsets should not be plotted.

8. The plotting of offsets should be continued according to the sequence maintained in the field book.

9. The main stations, substations, chain line, objects, etc. should be shown as per standard symbols

10. The conventional symbols used in the map should be shown on the right-hand side.

11. The scale of the map is drawn below the heading or in some suitable space. The heading should be written on the top of the map.

12. Unnecessary lines, objects etc. should be erased.

13. The map should not contain any dimensions.

Inking of the map

The inking should be begun from the left-hand-side towards the right-hand-side, and from the top towards the bottom.

Colouring of the map

In general, colour washing of engineering survey maps is not recommended. However, if it is necessary, the colour shades should be very light, and according to the colour conventions. The colouring should also be started from the left-hand-side towards the right and from the top towards the bottom.