FW01 — Pacing and Determination of Pace Factor - Theory & Concepts

FW01 — Pacing and Determination of Pace Factor

$Learning Objectives$

Establish an accurately measured reference baseline for pace calibration.
Apply the course convention that one step is counted as one pace.
Perform at least seven calibration trials and preserve every raw observation.
Exclude one highest and one lowest calibration count before determining the representative mean.
Determine an individual pace factor from the retained calibration trials.
Estimate an unknown horizontal distance by pacing and compare it with an independent reference measurement.
Prepare complete, traceable Fieldwork Data in accordance with FW00.

$Course Pace Convention$

For this subject, one normal step equals one pace. Every footfall that advances the walker by one step increments the pace count by one. A left step and the following right step therefore count as two paces. This convention shall be used consistently in FW01 and in later activities whenever a pacing estimate is required.

$Pace Factor$

The horizontal distance represented by one counted pace for a specific person under the conditions in which the calibration was performed.

$Purpose of the Activity$

Pacing is a rapid approximate-distance method used in reconnaissance, preliminary layout, checking, and situations where high-precision distance measurement is not yet required. Because step length varies from person to person and changes with terrain, fatigue, footwear, and walking speed, each student must determine a personal pace factor from a known reference distance rather than assume a standard value.

The calibration baseline should be straight, reasonably level, unobstructed, and independently measured before pacing begins. The student shall walk naturally; deliberately lengthening or shortening the step defeats the purpose of calibration.

$Seven-Trial Trimmed Calibration$

A minimum of seven complete calibration trials shall be performed. Every raw count is tabulated. After all trials are complete, identify the single highest pace count and the single lowest pace count. These two extreme observations remain visible in the field record but are excluded from the calibration mean. The pace factor is computed from the remaining trials.

With exactly seven trials, this procedure leaves five retained observations. If more than seven trials are required, only one highest and one lowest observation are removed unless the instructor gives a different instruction. If extreme values are tied, remove only one observation at the upper extreme and one at the lower extreme and clearly mark which trials were excluded.

Trimmed Mean Pace Count

Calculates the representative calibration count after removing one highest and one lowest observation.

\overline{N}_{\text{trim}}=\frac{\sum N_i-N_{\max}-N_{\min}}{n-2}

Variables

Symbol	Description	Unit
$\overline{N}_{\text{trim}}$	trimmed mean pace count	-
$N_i$	individual raw calibration pace counts	-
$N_{\max}$	single highest observed pace count removed from the mean	-
$N_{\min}$	single lowest observed pace count removed from the mean	-
$n$	total number of completed calibration trials, with n at least 7	-

Individual Pace Factor

Determines the calibrated horizontal distance represented by one counted step or pace.

PF = \frac{D_{\text{ref}}}{\overline{N}_{\text{trim}}}

Variables

Symbol	Description	Unit
$PF$	pace factor in meters per pace	-
$D_{\text{ref}}$	known horizontal reference distance in meters	-
$\overline{N}_{\text{trim}}$	trimmed mean pace count from the retained calibration trials	-

Paced Distance

Estimates an unknown horizontal distance using the calibrated pace factor.

D_{\text{paced}} = \overline{N}_{\text{unknown}} PF

Variables

Symbol	Description	Unit
$D_{\text{paced}}$	distance estimated by pacing	-
$\overline{N}_{\text{unknown}}$	average pace count over the unknown line	-
$PF$	calibrated pace factor	-

Pacing Percentage Error

Expresses the absolute pacing discrepancy relative to the independently measured reference distance.

\%E = \frac{\left|D_{\text{paced}}-D_{\text{check}}\right|}{D_{\text{check}}}\times 100

Variables

Symbol	Description	Unit
$\%E$	absolute percentage error	-
$D_{\text{paced}}$	distance determined using pacing	-
$D_{\text{check}}$	independently measured check distance	-

$Equipment and Site Preparation$

STEP-BY-STEP

Wear the hard hat and high-visibility vest required by FW00 and inspect the work area for pedestrian, vehicle, slope, and surface hazards.
Prepare a steel or fiberglass tape, ranging rods or station markers, field notebook/data sheet, calculator, and marking materials.
Select an unobstructed calibration line that is preferably 30 m to 50 m long or use the instructor-assigned baseline.
Establish clear terminal points such as C-01 and C-02 and determine the horizontal reference length independently by taping or another instructor-approved method.
Confirm before the first trial that one step equals one pace. Count each advancing footfall once; do not count a two-step stride as one pace.

$Calibration Field Procedure$

STEP-BY-STEP

Stand at the starting station in a normal, relaxed posture and walk naturally toward the end station without deliberately lengthening or shortening the step.
Count every individual step as one pace and record the count immediately after completing the line.
Perform at least seven complete calibration trials. Alternate walking direction where practical to reduce directional and starting-position bias.
Tabulate every trial number, direction, and raw pace count before any value is excluded.
Identify the single highest and single lowest raw pace counts. Mark them as excluded from the calibration mean, but do not erase or overwrite them.
Compute the trimmed mean from all remaining calibration trials.
Determine the individual pace factor from the known baseline and the trimmed mean.

$Unknown-Distance Check$

STEP-BY-STEP

Select an unknown line different from the calibration baseline and identify its terminal stations.
Pace the unknown line repeatedly using the same one-step-per-pace convention and normal walking technique. Use at least five complete trials unless the instructor requires more.
Tabulate every unknown-line trial and compute the mean pace count.
Determine the paced distance using the calibrated pace factor.
Measure the unknown line independently by tape or another approved reference method.
Determine the discrepancy and percentage error between the paced and check distances.
Record site conditions that may have affected pacing, including slope, surface, crowding, obstacles, rain, or unusual interruptions.

$Required Fieldwork Data and Tables$

Project title, location, date, survey type, group number, and weather/site condition.
Names of team members and assigned roles.
Equipment description and identification number when available.
Calibration station IDs and independently measured reference distance.
Explicit statement that one step was counted as one pace.
Calibration Measurement Table: at least seven raw trials with trial number, direction, raw pace count, status, and retained pace-count input.
Clear identification of the single highest and single lowest excluded calibration observations while preserving them in the raw record.
Unknown-Line Check Table: at least five raw unknown-line trials with trial number, direction, and pace count.
Computed Data Summary Table: trimmed mean calibration count, adopted pace factor, mean unknown-line count, paced distance, independent check distance, discrepancy, and percentage error.
SVG or equivalent field sketch showing the calibration and unknown lines, station IDs, dimensions, pedestrian/vehicle constraints when relevant, and reference orientation.

$Do Not Delete Extreme Trials$

Removing the highest and lowest observations means excluding them from the calibration computation only. The original values must remain visible in the raw-data table and be marked as excluded. Deleting, overwriting, or replacing an extreme observation would violate the FW00 raw-data integrity requirement.

$Limits of Pacing$

Pacing is an approximate field method and shall not be presented as a cadastral, legal-boundary, structural-control, or high-precision construction measurement. A good pacing result demonstrates calibration and consistency; it does not replace an instrument or direct measurement method when project tolerances require greater accuracy.

$Submission Timing and Data Integrity$

Submit the Fieldwork Data under DATA FOR FIELDWORK within the scheduled 3-hour class period. Submit the Full Fieldwork Report on the next class meeting. Preserve every raw pace count and reference measurement; any excluded extreme remains part of the submitted raw data.

$Quality Check Before Leaving the Site$

Verify that at least seven calibration trials are recorded and tabulated.
Confirm that every individual step was counted as one pace throughout the activity.
Confirm that exactly one highest and one lowest calibration count are marked as excluded from the calibration mean.
Verify that at least five calibration observations remain for the pace-factor computation.
Confirm that at least five unknown-line trials are tabulated separately from the calibration trials.
Recheck station IDs and independently measured reference lengths.
Confirm units on every distance and pace-factor value.
Compute the trimmed calibration mean, pace factor, unknown-line mean, paced distance, discrepancy, and percentage error while still on site.
Note any interrupted or invalid trial separately; do not silently replace it with another value.
Confirm that the field sketch and site-condition notes are complete.

FW01 — Required Data Tabulation

Use this structure as the minimum field or research data table. Add columns when the activity requires more detail.

Trial	Direction	Raw pace count	Status	Retained count / PF input
1	C-01 → C-02	Record count	Retained / Excluded	Record if retained
2	C-02 → C-01	Record count	Retained / Excluded	Record if retained
3	C-01 → C-02	Record count	Retained / Excluded	Record if retained
4	C-02 → C-01	Record count	Retained / Excluded	Record if retained
5	C-01 → C-02	Record count	Retained / Excluded	Record if retained
6	C-02 → C-01	Record count	Retained / Excluded	Record if retained
7	C-01 → C-02	Record count	Retained / Excluded	Record if retained

Complete all seven calibration trials and keep every raw count visible. Exclude exactly one highest and one lowest count from the trimmed mean while retaining both in the raw record. Prepare a separate unknown-line table with at least five trials, and a computed-data summary table for the trimmed mean, pace factor, unknown-line mean, paced distance, independent check distance, discrepancy, and percent error.

FW01 — Grading Rubric

Award points according to the evidence shown for each criterion.

Total: 25 pts

Criterion	Full-credit evidence	Points
Field technique and safety	Natural one-step-per-pace technique, proper baseline use, safe conduct, and correct field roles.	5
Calibration data and tabulation	Seven raw calibration trials are complete, traceable, correctly labeled, and the single highest/lowest observations remain visible while marked excluded from the mean.	6
Trimmed mean and pace-factor computation	Correct exclusion of one highest and one lowest trial, correct five-observation trimmed mean, units, and pace factor.	6
Unknown-distance check and error analysis	At least five unknown-line trials, independent check distance, paced estimate, discrepancy, and percent error are correctly determined and interpreted.	4
Field record and report quality	Complete metadata, field sketch, conditions, assumptions, required tables, and on-time traceable submission.	4
Total		25 / 25

Scoring guide: full credit for complete, technically correct, traceable evidence; reduce proportionally for minor errors, incomplete work, or weak documentation.

Key Takeaways

In this course, one step equals one pace.
Pace factor is person-specific and must be calibrated from a known horizontal distance.
At least seven calibration trials are required; all are tabulated, then one highest and one lowest observation are excluded from the calibration mean.
Extreme trials remain part of the raw record even when excluded from computation.
The unknown paced distance must be checked against an independent measurement using a separate observation table.
FW00 safety, naming, timing, and documentation requirements apply to the entire activity.

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