Tape (surveying)

Tapes are used in surveying for measuring Horizontal, vertical or slope distances. Tapes are issued in various lengths and widths and graduated in variety of ways.^[1] The measuring tapes used for surveying purposes are classfied in 4 types according to the material from which they are manufactured:

1. Linen or Cloth Tape. It is made of linen cloth with brass handle at zero end whose length is included in the tape length. It is very light and handy, but cannot withstand much wear and tear. So it cannot be used for accurate work. It is little used in surveying except for taking subsidiary measurements like offsets.
2. Metallic Tape. The tape is reinforced with copper wires to prevent stretching or twisting of fibres and is then called as metallic tape. They are available in many lengths but tapes of 20 m and 30 m are more commonly used.^[2]
3. Steel Tape. It is made of steel ribbon varying in width from 6 mm to 16 mm. It is available in lengths of 1, 2, 10, 30 and 50 metres. It cannot withstand rough usage and therefore it should be used with great care.
4. Invar Tape. It is made of an alloy of steel (64%) and nickel (36%). It is 6 mm wide and is available in lengths of 30 m, 50 m and 100 m. It is costly and delicate and should be thus handled with great care.^[3]

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