Linear Measurement and Basic Field Surveying

Introduction and context

Surveying begins with the determination of the relative positions of points on, above, or below the Earth’s surface. Although modern instruments can measure distances electronically and record coordinates automatically, the fundamental principles remain those of distance, direction, elevation, reference stations, and accurate field records. Linear measurement is therefore not merely the act of measuring a line; it is the controlled determination of horizontal distance between points under stated conditions.

In construction technology, reliable linear measurement supports site layout, building setting-out, road alignment, earthwork calculation, boundary definition, quantity surveying, and as-built documentation. Errors in a baseline can propagate through an entire survey and cause misplaced foundations, incorrect road widths, or disputes concerning property boundaries.

This chapter examines chain and tape surveying, ranging, chaining procedures, corrections, offsets, obstacle treatment, electronic distance measurement, field-book preparation, and conventional plan preparation. The emphasis is on the relationship between measurement theory and competent field practice.

Learning objectives

By the end of this chapter, the learner should be able to:

1. Explain the principles and limitations of chain, tape, and electronic distance measurement.
2. Range and measure straight survey lines safely and systematically.
3. Apply corrections for standard length, temperature, pull, sag, slope, and incorrect alignment.
4. Establish and record perpendicular and oblique offsets.
5. Determine distances across obstacles using suitable geometric procedures.
6. Prepare an organized field book and convert observations into a conventional survey plan.
7. Evaluate sources of error and select appropriate equipment and procedures for construction work.

1. Fundamental concepts and terminology

1.1 Distance and horizontal distance

A ground measurement is often made along a slope, but plans normally require horizontal distance. If a line has slope distance L and vertical difference h, its horizontal distance D is obtained from the right triangle:

Here, D and L have the same units, and h is the difference in elevation between the endpoints. This relationship assumes that the ground segment can be represented by a straight line and that curvature and refraction are negligible for ordinary construction distances. If the slope angle θ to the horizontal is known, then:

For a small vertical difference, the approximate horizontal distance may also be calculated from the slope gradient, but the exact trigonometric expression is preferred when reliable angle or elevation data are available.

1.2 Survey stations and lines

A survey station is a fixed, identifiable point at which a line begins, ends, or changes direction. Stations may be main stations, subsidiary stations, tie stations, or check stations. A survey line joins two stations. The principal line or baseline provides the framework from which other points are located.

A ranging line is the straight line between two stations. Ranging is the process of placing intermediate ranging rods so that they lie on this straight line. Chaining traditionally means measuring a line with a chain, although the term is often used generally for linear measurement.

An offset is a lateral distance from a survey line to locate a detail such as a wall, fence, tree, drain, road edge, or building corner. Offsets may be perpendicular or oblique.

1.3 Accuracy, precision, and error

Accuracy describes closeness to the true or accepted value; precision describes the consistency of repeated measurements. A measurement can be precise but inaccurate if a systematic error remains uncorrected.

Errors are commonly classified as:

• Systematic errors: predictable errors caused by tape length, temperature, pull, sag, or a constant instrument bias. They can often be estimated and corrected.
• Random errors: small, irregular variations caused by reading, marking, or environmental conditions. Repetition and averaging reduce their influence.
• Mistakes or blunders: avoidable errors such as miscounting tape lengths, booking a value in the wrong column, or omitting a station. They require detection and correction, not statistical adjustment alone.

A useful quality-control principle is to measure important lines independently or to close the survey on a known point. Agreement between independent determinations provides evidence of reliability.

2. Equipment for linear measurement

2.1 Chains

A surveyor’s chain consists of linked steel elements, commonly 20 m or 30 m long, with handles at the ends and tally markers at regular intervals. Metric chains are divided into links; the total length depends on the number and length of links. Chains are robust and suitable for ordinary ground, but joints can wear, links can bend, and the chain may not remain straight under inadequate tension.

A chain should be examined before use for broken or stretched links, damaged handles, illegible tallies, and accumulated dirt. Its length should be compared with a certified standard when precision is important.

2.2 Tapes

Common tapes include linen, metallic, steel, invar, and synthetic or fiberglass tapes.

A steel tape is normally preferred for construction measurements requiring greater accuracy than a chain. Tape graduations must be read at right angles to the tape to avoid parallax, and the tape should not be dragged over abrasive surfaces.

2.3 Ranging equipment

Ranging rods are straight, pointed rods with alternating colored bands that make them visible at a distance. Arrows or chaining pins mark the ends of completed tape or chain lengths. Plumb bobs transfer points vertically to the ground where vegetation, slopes, or structures make direct marking difficult. Pegs, nails, chalk, paint, and masonry marks may be used to preserve stations.

Line rangers, optical squares, cross-staffs, and prism squares assist in establishing perpendicular offsets. A hand level or clinometer can help identify approximate horizontal alignment, while a level instrument or total station provides more controlled height and distance data.

2.4 Electronic distance measurement

Electronic distance measurement (EDM) instruments determine distance from the travel time or phase difference of electromagnetic radiation. In a total station, EDM is integrated with angle measurement and data recording. Reflectorless instruments can measure some surfaces without a prism, although surface color, texture, incidence angle, and range affect performance.

A simplified principle for time-of-flight EDM is:

where D is the instrument-to-target distance, v is the propagation velocity of the signal through the atmosphere, and t is the measured round-trip travel time. The factor 2 occurs because the signal travels to the target and back. Practical instruments use calibration constants, atmospheric corrections, phase measurement, and signal-processing algorithms. The formula is conceptual rather than a complete instrument correction model.

Electronic measurement is efficient, but it is not automatically error-free. Prism constant, atmospheric conditions, poor pointing, unstable tripods, incorrect target identification, and wrong instrument settings can produce erroneous results. Digital records should therefore be checked against field observations and independent measurements.

3. Ranging and chaining procedures

3.1 Direct ranging on level or gently sloping ground

When the endpoints are intervisible, direct ranging is used. The rear station is occupied by an assistant holding a ranging rod. The leader moves toward the forward station carrying another rod. The surveyor standing behind the rear station signals the leader to move left or right until the intermediate rod appears exactly in line with the two end rods. The process is repeated until all required intermediate points are aligned.

The rod should be held vertical. On sloping ground, a rod leaning along the slope can introduce a lateral or longitudinal error. The surveyor should use clear, agreed signals and confirm the final alignment from both directions when practical.

3.2 Indirect ranging

If the endpoints are not intervisible because of a ridge, depression, vegetation, or a building, indirect ranging is required. Intermediate rods are positioned successively by reciprocal alignment. Two observers move rods until each can see the other intermediate rod aligned with an end station. Repetition is necessary because the first estimate is rarely exact.

Where visibility is seriously restricted, the line may be established using a total station, GNSS equipment, or a traverse around the obstruction. The selected method should preserve the intended geometric relationship rather than merely produce a visually plausible line.

3.3 Standard chaining procedure

A disciplined chaining operation includes the following sequence:

1. Reconnoitre the route, identify stations, and remove only necessary obstructions.
2. Mark and describe the initial and terminal stations.
3. Range the line and place intermediate rods.
4. Stretch the chain or tape between stations with the required tension.
5. Keep the tape straight and, where necessary, horizontal by stepping or plumbing.
6. Mark each full tape length with an arrow or pin.
7. Count full lengths and measure the final partial length carefully.
8. Call out and book readings immediately.
9. Measure offsets to detail points and record their direction and location.
10. Check important lines by repetition, an independent measurement, or a closing condition.

The leader carries the forward end and arrows; the follower controls the rear end and counts completed lengths. Roles should be exchanged periodically in repetitive work to reduce fatigue-related mistakes.

3.4 Measuring sloping ground

Three accepted methods are used:

• Direct measurement along the slope: measure slope distance and reduce it to horizontal distance using an angle or elevation difference.
• Stepping: hold the tape approximately horizontal in short segments, using a plumb bob to transfer the forward point to the ground.
• Optical or electronic measurement: determine horizontal distance directly or measure slope distance and vertical angle electronically.

Stepping is useful on steep or uneven ground but requires careful plumbing and marking. Each step should be short enough that the tape remains reasonably horizontal.

4. Corrections to measured distances

A measured distance is not necessarily the distance that should appear in the survey record. Corrections are applied when their magnitude is significant relative to the required accuracy.

Let L_m be the measured length and L_t the standardized or corrected length. A general corrected-distance expression may be written as:

where the terms represent corrections for standard length, temperature, pull, sag, alignment, and slope or reduction, respectively. The sign of each correction depends on the condition. Corrections should not be added mechanically without identifying whether the measured tape was effectively too long, too short, too warm, too highly or insufficiently pulled, or not horizontal.

4.1 Correction for standard length

If the actual tape length is l_a and its nominal length is l_n, the correction for a measured distance L_m is:

Thus, if a 30 m tape is actually 30.006 m long, a distance measured with it is too small and C_s is positive. The formula assumes that the tape’s error is uniform along its length.

4.2 Temperature correction

For a tape with coefficient of linear expansion α, standard temperature T₀, and field temperature T, the temperature correction is:

Here, α has units of inverse temperature, such as °C⁻¹. If the tape is warmer than its standard temperature, it becomes longer and the uncorrected measured distance is too small; the correction is positive. The expression assumes uniform temperature and a freely expanding tape.

4.3 Pull correction

If the applied pull P differs from the standard pull P₀, the approximate pull correction for a tape of cross-sectional area A and elastic modulus E is:

For a steel tape, E is large, so the correction is often small in ordinary work. Units must be consistent: force in newtons, area in square metres, and modulus in pascals.

4.4 Sag correction

A tape supported only at its ends sags into a curve. The measured distance along the sagging tape is longer than the horizontal distance between supports, so the sag correction is negative. For a tape span of length l supported at its ends, with uniform tape weight per unit length w and applied pull P, the approximate correction is:

For several equal spans, calculate the correction for each span and sum the results. This formula assumes a flexible tape, uniform loading, level supports, and a parabolic approximation to the sag curve. The best practical control is to support the tape at short intervals or apply the specified tension.

4.5 Alignment correction

If a tape is not aligned with the true line, its measured path is generally longer than the desired straight distance. For a small lateral displacement d over a line length L, the approximate correction is:

This is a small-angle approximation. The correction is negative because the misaligned path exceeds the straight distance. Correct ranging is normally more effective than attempting to calculate a large alignment error afterward.

4.6 Slope correction

For a slope distance L and vertical difference h:

The correction is negative because horizontal distance is less than slope distance. If the slope angle θ is measured, D = L cos θ. For very long lines, geodetic curvature and atmospheric refraction may also need consideration, but these are normally outside routine building-site chaining.

Worked example: standardized and horizontal distance

A nominal 30 m steel tape is actually 30.006 m long at 20 °C. A line is measured as 120.000 m at 30 °C using a pull equal to the standard pull. The tape has α = 11.6 × 10^-6 °C⁻¹. The endpoints differ in elevation by 4.000 m. Ignore sag and alignment.

Standard-length correction:

C_s = ((30.006 − 30.000)/30.000) × 120.000 = 0.024 m

Temperature correction:

C_t = 11.6 × 10^-6 × (30 − 20) × 120.000 = 0.01392 m

Corrected slope distance:

L = 120.000 + 0.024 + 0.01392 = 120.03792 m

Horizontal distance:

D = √(120.03792² − 4.000²) ≈ 119.971 m

Thus, the horizontal distance is approximately 119.971 m. The calculation assumes uniform tape properties, correct temperature measurement, and negligible pull, sag, and alignment errors.

5. Offsets and locating details

Offsets connect the survey framework to physical features. A good offset is short, unambiguous, and easy to re-establish. Perpendicular offsets are preferred because their geometry is simple and their position along the chain line can be recorded clearly.

5.1 Perpendicular offsets

A cross-staff, optical square, prism square, or total station can establish a right angle. Without an instrument, a right triangle can be formed using the 3–4–5 relationship: if three points are separated by 3 units, 4 units, and 5 units, the angle opposite the 5-unit side is 90°. This is a geometric construction rather than a special unit requirement; 3 m, 4 m, and 5 m or 6 m, 8 m, and 10 m are equivalent in principle.

Offsets should be recorded with the chainage of the foot of the offset and the offset length. The side should be identified as left or right when looking in the direction of increasing chainage.

5.2 Oblique offsets and ties

An oblique offset is measured at an angle other than 90°. It may be useful where a perpendicular line is blocked or where a feature is best located from two accessible stations. Record both the distance and the endpoints or angle-defining information. A tie line joins a subsidiary station to a nearby detail and helps locate features or check the survey framework.

5.3 Offset selection

Straight boundaries may be located with offsets at their endpoints and at changes in direction. Irregular boundaries require more offsets: close spacing where curvature changes rapidly and wider spacing where the boundary is straight. The objective is not to collect the greatest number of offsets but to represent the feature sufficiently for accurate plotting and later identification.

6. Overcoming obstacles

Obstacles may prevent chaining, ranging, or both. The correct method depends on the type of obstruction.

6.1 Example: measuring across an obstacle

Suppose a straight survey line from A to B crosses a pond. Points A and B are visible, but direct chaining is impossible. Select accessible points C and D on one side of the pond so that AC and BD can be measured and the geometry allows the line AB to be reconstructed. A practical field solution may use equal perpendiculars: construct perpendiculars at A and B, select points C and D at equal known distances on the same side, and measure CD. If the construction is geometrically controlled, CD is parallel and equal to AB. In practice, equal distances and right angles must be established carefully, and the result should be checked independently.

For more demanding work, observe a triangle with a total station. If a baseline and sufficient angles are measured, the obstructed distance can be computed using triangle geometry. The selected configuration should avoid very small angles, which amplify observational error.

7. Field-book preparation

The field book is a legal, technical, and operational record. It should allow another competent person to understand what was measured, where it was measured, and how the plan can be reproduced.

7.1 Booking conventions

A field book should contain:

• project title, location, date, crew, weather, and equipment;
• tape or chain identification and calibration information;
• station descriptions and reference ties;
• line direction and chainage;
• offsets, feature descriptions, and left/right notation;
• measurements in consistent units;
• corrections or reduction procedures where applicable;
• sketches that clarify the geometry;
• checks, remarks, and initials of the observer and recorder.

In a conventional chain-survey field book, the chain line is represented by a central line. Chainages are written along it, and details are sketched on the appropriate side. A single-line field book is useful for ordinary work because it shows the measured line and offsets. A double-line field book may be used where two parallel lines or more complex details must be represented.

7.2 Good booking practice

Record observations immediately, never from memory. Use a consistent number of decimal places appropriate to the instrument and required accuracy. Do not erase an error in a way that destroys the original record; strike through it once, enter the corrected value, and initial the change. Distinguish observed values from calculated values. Every station should have a stable physical description, such as “iron nail at southwest corner of concrete slab,” rather than only a temporary peg.

A field sketch is not required to be to scale, but it must be topologically correct: features shown on the left in the field should not be plotted on the right, and crossings, junctions, and station relationships must be clear.

8. From field book to conventional survey plan

The plan is prepared by plotting the framework first and details second. A typical workflow is:

1. Select a scale suitable for the site and required detail.
2. Plot the principal line and stations using corrected or reduced distances.
3. Plot subsidiary and check lines.
4. Construct perpendicular and oblique offsets from the recorded chainages.
5. Join boundary and structural points using appropriate conventional symbols.
6. Add north arrow, title, scale, legend, station labels, dimensions, and benchmark information.
7. Check closure, feature relationships, and agreement between independent observations.
8. Preserve the original field book and document all computations.

The conventional scale relationship is:

where S is the representative fraction, d is the distance on the plan, and D is the corresponding ground distance, expressed in the same units. For a 1:500 scale, 1 unit on the plan represents 500 of the same units on the ground. If a ground distance is 24.00 m, its plan length at 1:500 is:

d = 24.00/500 = 0.048 m = 48 mm

Scale choice involves a compromise: a large scale shows more detail but covers less area; a small scale covers more area but may conceal construction-relevant detail.

9. Quality control, safety, and professional responsibility

9.1 Quality control

Before accepting measurements, verify that:

• the tape or EDM has a current calibration or stated accuracy;
• stations are stable and clearly described;
• ranging rods are vertical and lines are correctly aligned;
• tape tension and support conditions are consistent;
• slope reduction and corrections use compatible units;
• chainages increase logically and offsets are not duplicated;
• at least one independent check exists for critical dimensions;
• electronic files are backed up and field codes are interpretable.

A closure error should be examined for blunders before any adjustment is made. Adjustment distributes residual error only when observations are believed to contain random error and the survey specification permits adjustment.

9.2 Safety

Survey crews work near traffic, excavation edges, plant, overhead conductors, water, and unstable ground. High-visibility clothing, boots, helmets, communication procedures, traffic control, and safe instrument positions are essential. A ranging rod is conductive and must never be raised near overhead electrical lines. Surveyors should not enter unsafe excavations merely to obtain a measurement; use remote or offset methods instead.

9.3 Legal and ethical considerations

Boundary surveys may have legal consequences and should be performed only within the competence, authority, and licensing requirements of the jurisdiction. Survey records must not be altered to support a desired result. When an observation is uncertain, the uncertainty should be stated rather than concealed. Personal data, landowner information, and digital location data should be handled in accordance with applicable privacy and professional regulations.

10. Technology and contemporary practice

Total stations, robotic instruments, GNSS receivers, laser distance meters, mobile mapping systems, and building-information-model workflows have transformed field surveying. Artificial intelligence can assist with feature recognition, anomaly detection, automated coding, and quality checks, but it does not replace survey control, calibration, professional judgment, or responsibility for the final record.

A robust contemporary workflow combines technologies rather than assuming that one instrument is universally superior. GNSS may be effective in open areas but unreliable near buildings or trees. Total stations provide high-quality relative geometry where line of sight exists. Laser scanners capture dense point clouds but require registration and interpretation. Tape measurements remain valuable for short checks, accessibility, and independent verification.

Applied case: illustrative construction-site baseline

Background

A contractor must set out the foundation line of a small laboratory on a sloping site. The design requires a 42 m horizontal baseline between control points P and Q. A steel tape is available, and a total station can provide an independent check.

Problem

The ground distance is measured along a slope. The tape is 30.004 m long rather than its nominal 30.000 m length, and the field temperature is 28 °C while the standard temperature is 20 °C. The tape coefficient is 11.6 × 10^-6 °C⁻¹. The observed slope distance is 42.015 m, and the elevation difference between P and Q is 1.20 m. Pull and sag corrections are negligible for this short, carefully supported measurement.

Analysis and solution

Standard-length correction:

C_s = ((30.004 − 30.000)/30.000) × 42.015 = 0.00560 m

Temperature correction:

C_t = 11.6 × 10^-6 × (28 − 20) × 42.015 ≈ 0.00390 m

Corrected slope distance:

L = 42.015 + 0.00560 + 0.00390 = 42.02450 m

Horizontal distance:

D = √(42.02450² − 1.20²) ≈ 42.007 m

The corrected horizontal distance is approximately 42.007 m. The surveyor records the value, the assumptions, and the correction computation. The total station independently reports 42.009 m, a difference of approximately 0.002 m. Whether this is acceptable depends on the project specification, but the close agreement supports use of the baseline for ordinary foundation setting-out.

Outcome and learning points

The case demonstrates that a seemingly small tape-length and temperature error can influence a construction dimension, while slope reduction must not be omitted. It also shows the value of independent checking. The field book should retain the raw observation, correction data, final horizontal distance, instrument information, and acceptance decision.

Limitations and selection of methods

Chain and tape surveying are economical and transparent, but their accuracy depends heavily on crew discipline, terrain, tension, alignment, and environmental conditions. They become inefficient in congested or extensive sites. EDM and total stations improve speed and reduce manual booking, but require calibration, line of sight, battery management, competent setup, and data validation. GNSS can provide coordinates over large areas but may suffer from multipath, obstruction, poor satellite geometry, and reference-system errors.

The professional surveyor therefore selects a method according to required accuracy, terrain, visibility, legal significance, available control, and consequences of error. No instrument compensates for poor station identification or inadequate records.

Chapter Summary

Linear measurement is the controlled determination of distance, usually horizontal distance, between survey points. Chains and tapes remain important for basic and construction surveying, while EDM and total stations provide efficient electronic alternatives. Accurate work requires stable stations, correct ranging, horizontal measurement or proper slope reduction, careful offsetting, and immediate field booking.

Measured distances may require corrections for standard tape length, temperature, pull, sag, alignment, and slope. Corrections must be applied with correct signs, units, assumptions, and awareness of their applicability. Offsets locate physical details relative to a survey framework, and obstacles are overcome through auxiliary geometry, reciprocal ranging, triangulation, traversing, or electronic observation.

A field book is a permanent technical record, not a rough memory aid. It must identify stations, chainages, offsets, features, conditions, checks, and calculations. The survey plan is produced by plotting the controlled framework before details and by including scale, orientation, symbols, dimensions, and quality checks. Modern technologies improve productivity but require calibration, independent verification, and professional judgment. Safe and ethical practice is inseparable from technical accuracy.

Key Terms

Accuracy: Closeness of a measurement to the true or accepted value.

Alignment correction: Correction for measuring away from the intended straight line.

Chainage: Distance measured along a survey line from a defined starting station.

Chaining: Measuring a line using a chain or, more generally, a tape-based distance procedure.

Check line: An independently measured line used to test the accuracy of a survey framework.

EDM: Electronic distance measurement using electromagnetic signals.

Field book: The organized field record of observations, sketches, stations, and conditions.

Horizontal distance: The plan distance between two points after removal of slope effects.

Offset: A lateral measurement from a survey line to locate a detail.

Oblique offset: An offset measured at an angle other than 90° to the survey line.

Perpendicular offset: An offset established at a right angle to the survey line.

Random error: Irregular measurement variation that cannot be predicted exactly.

Ranging: Aligning intermediate points between two survey stations.

Representative fraction: The ratio of plan distance to corresponding ground distance.

Sag correction: Correction for the excess length caused by a tape hanging between supports.

Station: A fixed point defining the beginning, end, or change of a survey line.

Systematic error: A predictable error with a consistent cause or pattern.

Tie line: A line connecting a survey station to a detail or subsidiary station.

Total station: An electronic instrument combining angle measurement, EDM, computation, and data recording.

Vertical difference: Difference in elevation between two points.

Review Questions

Short Answer Questions

1. Distinguish between accuracy and precision in surveying.
2. What is the purpose of ranging before chaining a line?
3. Why is slope distance reduced to horizontal distance for plotting?
4. Define a perpendicular offset and state one instrument used to establish it.
5. List four items that should appear in a field book.

Long Answer Questions

1. Explain the complete field procedure for measuring a straight line with a steel tape, including crew duties, ranging, marking, booking, and checking.
2. Discuss the principal corrections applied to tape measurements and explain the sign and applicability of each.
3. Compare chains, steel tapes, EDM instruments, and total stations for construction surveying.
4. Explain how offsets are used to locate boundaries and site details, including the treatment of irregular features.
5. Describe how a conventional survey plan is prepared from field-book observations.

Analytical / Application Questions

1. A 50 m tape is 50.008 m long at its standard temperature. A line is measured as 200.000 m at a temperature 12 °C above standard, with α = 11.6 × 10^-6 °C⁻¹. Calculate the standard-length and temperature corrections, assuming all other corrections are negligible.
2. A measured slope distance is 75.000 m and the difference in elevation is 3.000 m. Calculate the horizontal distance and explain why the result is less than the slope distance.
3. A proposed baseline crosses a fenced, inaccessible area, although both endpoints are visible. Recommend a field method, describe the control observations required, and explain how you would independently check the resulting distance.

Multiple Choice Questions with Answers

Question 1

Which quantity is normally required for plotting a measured line on a horizontal survey plan?

A. Horizontal distance

B. Slope distance only

C. Tape temperature only

D. Vertical difference only

Correct Answer: A. Horizontal distance

Question 2

A tape is actually longer than its nominal length. Before correction, the measured distance is generally:

A. Too large

B. Too small

C. Unaffected

D. Equal to the vertical difference

Correct Answer: B. Too small

Question 3

Which correction is negative because a sagging tape is longer than the straight horizontal distance between its supports?

A. Temperature correction

B. Standard-length correction

C. Sag correction

D. Pull correction

Correct Answer: C. Sag correction

Question 4

What is the principal purpose of ranging rods?

A. To measure temperature

B. To establish a straight line between stations

C. To calculate tape tension

D. To determine atmospheric pressure

Correct Answer: B. To establish a straight line between stations

Question 5

An offset measured at 90° to a chain line is called a:

A. Tie line

B. Check line

C. Oblique offset

D. Perpendicular offset

Correct Answer: D. Perpendicular offset

Question 6

If a slope distance is 100 m and the elevation difference is 6 m, which expression gives the horizontal distance?

A. 100 + 6

B. 100 − 6

C. √(100² − 6²)

D. 100² + 6²

Correct Answer: C. √(100² − 6²)

Question 7

At a scale of 1:500, a ground distance of 25 m is represented by:

A. 5 mm

B. 25 mm

C. 50 mm

D. 125 mm

Correct Answer: C. 50 mm

Question 8

Which instrument combines electronic distance measurement with electronic angle measurement?

A. Total station

B. Cross-staff

C. Chain

D. Plumb bob

Correct Answer: A. Total station

Question 9

Which field-book practice is most appropriate?

A. Record observations from memory at the end of the day

B. Erase incorrect readings completely

C. Record observations immediately with station and feature descriptions

D. Omit units when all measurements use the same tape

Correct Answer: C. Record observations immediately with station and feature descriptions

Question 10

If a tape is warmer than its standard temperature, the temperature correction for an ordinary tape is generally:

A. Positive

B. Negative

C. Always zero

D. Equal to the slope correction

Correct Answer: A. Positive