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Table 5.1 Accuracy standards for vertical control surveys

Order Maximum allowable Applications

error of closure, mm

First

Class I + 3√ k Provides basic framework for the national control

Class II + 4√ k network and precise control of large engineering

projects and scientific studies

Second

Class I + 6√k Adds to the basic framework, for major engineering

Class II + 8√ k projects

Third + 12√k Serves as vertical reference for local engineering,

topo, drainage, and mapping projects

Exercise

1. A differential leveling loop began and closed on BM bridge (elevation
1237.28 ft). The BS and FS distances were kept approximately equal. Readings
taken in order are 8.59 on BM bridge, 6.54 and 4.87 on TP1, 7.50 and 6.08 on BM
X, 7.23 and 2.80 on TP2, and 1.11 on BM bridge. Prepare, check and adjust the
notes.
2. A level setup midway between X and Y reads 5.18 on X and 6.80 on Y.
When moved within a few feet of X, readings of 4.74 on X and 6.32 on Y are
recorded. What is the true elevation difference, and the reading required on Y to

adjust the instrument?
3. Reciprocal leveling gives the following readings in feet from setup near A:
on A, 2.071; on B, 8.254, 8.259 and 8.257. At the setup near B, 9.112; on A, 2.926,
2.930, and 2.927. The elevation of B is 1099.60. Compute the misclosure and the
elevation of A.
4. Prepare a set of three-wire leveling notes for the data given and make the
page check. The elevation of BM X is 230.054m. Rod readings(in meter) are:
BS on BM X: H = 1.683, M = 1.453, L = 1.224: FS on
TP1: H = 2.959, M = 2.707, L = 2.454; BS on
TP1: H = 2.254, M = 2.054, L = 1.854; FS on
BM Y: H = 1.013, M = 0.817, L = 0.620.
5. If the elevation on a certain project at stations 10+00 and 14+00 are 1232.47
and 1248.06, respectively, what is the percent grade connecting these points?
6. In trigonometric leveling from point A to point B, the slope distance and
0
zenith angle measured at A were 23051.82 ft and 83 41'16". At B these
0
measurements were 23051.85ft and 96 21'31", respectively. If the instrument and
rod target height were equal, calculate the difference in elevation from A to B.
7. A pre-engineering baseline was run down a very steep hill. Rather than
measure horizontally downhill with the steel tape, the surveyor measured the
vertical angle with a theodolite and the slope distance with a 200' steel tape.
0
The vertical angle was -21 26' turned to a point on a plumbed range pole 4.88 ft
above the ground. The slope distance from the theodolite to the point on the range

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