The subsections that follow describe six steps in taping on level ground using a tape.
Lining In. Using range poles, the line to be measured should be marked at both ends, and at intermediate points where necessary, to ensure unobstructed sight lines. Taping requires a minimum of two people, a forward tapeperson and a rear tapeperson. The forward tapeperson is lined in by the rear tapeperson. Directions are given by vocal or hand signals.
Applying Tension. The rear tapeperson holding the 100-ft end of a tape over the first (rear) point lines in while the forward tapeperson, holding the zero end of the tape. For accurate results the tape must be straight and the two ends held at the same elevation.
A specified tension, generally between 10 and 25 lb, is applied. To maintain a steady pull, apepersons wrap the leather thong at the tape’s end around one hand, keep forearms against their bodies, and face at right angles to the line. In this position, they are off the line of sight. Also, the body need only be tilted to hold, decrease, or increase the pull. Sustaining a constant tension with outstretched arms is difficult, if not impossible, for a pull of 15 lb or more. Good communication between forward and rear tapepersons will avoid jerking the tape, save time, and produce better results.
Plumbing. Weeds, brush, obstacles, and surface irregularities may make it undesirable to lay a tape on the ground. In those cases, the tape is held above ground in a horizontal position. Placing the plumbbob string over the proper tape graduation and securing it with one thumb, mark each end point on the tape. The rear tapeperson continues to hold a plumb bob over the fixed point, while the forward tapeperson marks the length. In measuring a distance shorter than a full tape length, the forward tapeperson moves the plumb-bob string to a point on the tape over the ground mark.
Marking Tape Lengths. When the tape has been lined in properly, tension has been applied, and the rear tapeperson is over the point, “stick” is called out. The forward tapeperson then places a pin exactly opposite the zero mark of the tape and calls “stuck.” The marked point is checked by repeating the measurement until certainty of its correct location is assured.
After checking the measurement, the forward tapeperson signals that the point is OK, the rear tapeperson pulls up the rear pin, and they move ahead. The forward tapeperson drags the tape, paces roughly 100 ft, and stops. The rear tapeperson calls “tape” to notify the forward tapeperson that they have gone 100 ft just before the 100-ft end reaches the pin that has been set. The process of measuring 100-ft lengths is repeated until a partial tape length is needed at the end of the line.
Reading the Tape. There are two common styles of graduations on 100-ft surveyor’s tapes.It is necessary to identify the type being used before starting work to avoid making one-foot mistakes repeatedly. The more common type of tape has a total graduated length of 101 ft. It is marked from 0 to 100 by full feet in one direction, and has an additional foot preceding the zero mark graduated from 0 to 1 ft in tenths, or in tenths and hundredths in the other direction. In measuring the last partial tape length of a line with this kind of tape, a full-foot graduation is held by the rear tapeperson at the last pin set [like the 87-ft mark in Figure 6.2(a)]. The actual footmark held is the one that causes the graduations on the extra foot between zero and the tape end to straddle the closing point. The forward tapeperson reads the additional length of 0.68 ft beyond the zero mark. In the case illustrated, to ensure correct recording, the rear tapeperson calls “87.”The forward tapeperson repeats and adds the partial foot reading, calling “87.68.” Since part of a foot has been added, this type of tape is known as an add tape.
The other kind of tape found in practice has a total graduated length of 100 ft. It is marked from 0 to 100 with full-foot increments, and the first foot at each end (from 0 to 1 and from 99 to 100) is graduated in tenths, or in tenths and hundredths. With this kind of tape, the last partial tape length is measured by holding a full-foot graduation at the last chaining pin set such that the graduated section of the tape between the zero mark and the 1-ft mark straddles the closing point. This is indicated in Figure 6.2(b), where the 88-ft mark is being held on the last chaining pin and the tack marking the end of the line is opposite 0.32 ft read from the zero end of the tape.The partial tape length is then 88.0 0.32 87.68 ft.
The quantity 0.32 ft is said to be cut off; hence this type of tape is called a cut tape. To ensure subtraction of a foot from the number at the full-foot graduation used, the following field procedure and calls are recommended: rear tapeperson calls “88”; forward tapeperson says “cut point threetwo”; rear tapeperson answers “eighty seven point six eight”; forward tapeperson confirms the subtraction and replies “check” when satisfied it is correct.
An advantage of the add tape is that it is easier to use because no subtraction is needed when measuring decimal parts of a foot. Its disadvantage is that careless tapepersons will sometimes make measurements of 101.00 ft and record them as 100.00 ft. The cut tape practically eliminates this mistake.
The same routine should be used throughout all taping by a party and the results tested in every possible way. A single mistake in subtracting the partial foot when using a cut tape will destroy the precision of a hundred other good measurements. For this reason, the add tape is more foolproof. The greatest danger for mistakes in taping arises when changing from one style of tape to the other.
Recording the Distance. Accurate fieldwork may be canceled by careless recording. After the partial tape length is obtained at the end of a line, the rear tapeperson determines the number of full 100-ft tape lengths by counting the pins collected from the original set of 11. For distances longer than 1000 ft, a notation is made in the field book when the rear tapeperson has 10 pins and one remains in the ground. This signifies a tally of 10 full tape lengths and has traditionally been called an “out.” The forward tapeperson starts out again with 10 pins and the process is repeated. Since long distances are measured electronically today, tapes are typically used for distances less than 100 ft today.
Although taping procedures may appear to be relatively simple, high precision is difficult to achieve, especially for beginners. Taping is a skill that can best be taught and learned by field demonstrations and practice.