Field Notes
Part of Surveying
How to record survey measurements in the field so they can be reliably used, checked, and referenced in the future.
Why This Matters
A survey measurement that is not correctly recorded might as well not have been made. Field notes are the permanent record of everything measured in the field — every distance, every angle, every elevation, every description of the ground. When you return to your drawing table, when another surveyor checks your work, or when someone thirty years from now needs to re-establish a boundary, the field notes are the only resource they have.
Good field notes are not merely accurate — they are clear, complete, and organized so that a person who was not present in the field can reconstruct exactly what was done and reproduce the results. Poor field notes have caused legal disputes over land boundaries, construction failures due to misread grades, and the loss of irreplaceable survey data. In a rebuilding community, where institutional knowledge must be preserved across generations, field notes are a form of infrastructure as real as any road or building.
The discipline of good field notes also forces clearer thinking in the field. When you must write down what you did, you notice gaps in your procedure, catch inconsistencies, and confirm that your measurements make sense before leaving the site.
The Field Book
Materials: A dedicated book for survey notes, preferably with stiff covers to protect against field conditions. Waterproof paper or paper treated with wax is ideal; otherwise, keep the book in a waterproof wrapper. If manufactured notebooks are not available, make them from stitched folded sheets with a leather or bark cover.
Organization:
- Number all pages sequentially before beginning field work
- Devote the first two pages to an index: the date, location, and page numbers for each survey job
- Use one page spread per day or per survey job, not one page per measurement
- Never remove pages or paste over entries
Pencil versus ink: Pencil is traditional for field notes because it does not run in rain and does not require a dip pen. Use a medium-hard pencil (equivalent to HB or H) so marks are clear but not easily smeared. Never use charcoal or other impermanent materials.
What to Record on Every Page
Before any measurements, record this header information:
Date: [full date]
Project: [name or description]
Location: [specific enough to find on a map]
Weather: [temperature, wind, conditions]
Instrument: [level, compass, chain — and its serial number or description]
Party: [names and roles of everyone present]
Page: [number] of [estimated total]
This information seems tedious when writing it but is invaluable when reviewing notes months or years later.
Leveling Notes Format
Differential leveling notes use a standard columnar format that shows the full arithmetic of each setup:
STA BS(+) HI FS(-) ELEV NOTES
BM-1 2.34 40.34 38.00 Chiseled X on granite boulder
TP-1 1.86 40.78 1.42 38.92 Iron pin in soil
TP-2 2.10 41.45 1.43 39.35 Wood stake
BM-2 2.11 39.34 Spike in oak root base
Arithmetic check:
Sum BS = 6.30
Sum FS = 5.01 (wait — this should be 4.96... error, recheck FS at TP-1)
Columns:
- STA (Station): the point being measured
- BS (Backsight): rod reading on a known point, used to establish HI
- HI (Height of Instrument): elevation of the line of sight = previous elevation + BS
- FS (Foresight): rod reading on a new point, used to compute its elevation
- ELEV (Elevation): computed ground elevation = HI − FS
- NOTES: description of the point and any relevant observations
Arithmetic check: The elevation of the last point should equal the first elevation + (sum of all backsights) − (sum of all foresights). Check this before leaving the field. If it does not balance, an arithmetic error has been made.
Traverse Notes Format
When measuring a traverse (a series of connected lines between stations), record:
TRAVERSE: Farm boundary survey
FROM TO BEARING DISTANCE NOTES
A B N 42° 30' E 47.23 m A: iron pin at NE fence corner
B C S 88° 15' E 33.10 m B: stake in soft soil, TBM elev 42.11
C D S 12° 00' W 58.45 m C: large flat stone
D E N 78° 45' W 41.20 m D: oak tree bearing
E A N 03° 15' E 44.60 m (closure check - return to start)
Interior angles:
A: 135° 15'
B: 94° 45'
C: 191° 00'
D: 83° 30'
E: 135° 30'
Sum = 640° 00' Expected: (5-2)×180 = 540° ERROR - recheck angle at C
After each traverse, compute the angular closure before leaving the field. The sum of interior angles of an n-sided polygon should be (n−2) × 180°. Any significant discrepancy requires re-measurement before the crew disperses.
Sketches and Diagrams
Numbers alone are insufficient. Every field book page should include at least a rough sketch showing:
- The layout of measurement points and their relative positions
- Which direction is north (marked with an arrow)
- Reference ties: distances and bearings to permanent features
- Any obstacles, special conditions, or features that affect interpretation of the measurements
Sketching rules:
- Sketches do not need to be to scale, but proportions should be approximately correct
- Label every point with the same designation used in the measurement columns
- Draw north arrows on every sketch
- Indicate which measurements appear on which pages if a sketch spans multiple pages
A well-drawn sketch allows someone who was not present to reconstruct the geometry of the survey without needing to re-measure. It also catches blunders: if a measured angle looks wrong in the sketch, it probably is wrong.
Recording Errors and Corrections
When you make an error in your field notes, never erase or obliterate it. Draw a single line through the incorrect entry, write the correction above or beside it, and initial the correction. A record of corrections is evidence of honest work. Erasures suggest falsification.
If an entire measurement must be re-done, mark the original with “VOID” and a reason. Record the new measurement on the same or following page with a note referencing the voided entry.
TP-3 1.44 41.23 ←VOID (disturbed TP, re-measured below)
TP-3a 1.41 41.20 2.06 39.39 Reset stake 30 cm NW of original
Closing the Field Book
At the end of each day in the field, before the party disperses:
- Complete all arithmetic checks
- Ensure all measurements have sufficient description to re-locate the points
- Note any measurements that should be checked or re-done next session
- Record the condition of any monuments or benchmarks that appeared disturbed
A short summary note — “traverse closed within 0.03 m in 247 m perimeter; BM-2 confirmed; TBM set at stake D for next session” — takes two minutes and prevents countless questions later.
Copying: The field book itself is the primary record and should be stored safely. For working copies, transcribe only what is needed for calculation and drawing. Never work from the field book as a scratch pad — keep a separate calculation sheet. If the field book is lost or damaged, the survey must be repeated from scratch. Treat it accordingly.
The Only Record
Your field book is the legal and historical record of what was measured. In a land dispute, it is evidence. In a construction failure, it establishes what grades were set. In a future survey, it provides the only way to re-establish lost monuments. Write every entry as if someone’s livelihood depends on it — because someday it might.