Plotting and Recording

Part of Surveying

How to convert field measurements into accurate maps and permanent records.

Why This Matters

Field measurements are raw data. To be useful — for planning, decision-making, and communication — they must be converted into maps and drawings that represent the real world accurately and clearly. Plotting is the process of transferring field measurements onto paper to create these representations. Recording is the process of documenting both the raw measurements and the finished maps so that others can use, check, and build on them.

A community’s survey records are one of its most valuable intellectual assets. They represent years of accumulated measurement work that would take years to reproduce. They form the basis for all land agreements, infrastructure planning, and dispute resolution. A map that is plotted carelessly or stored poorly may be worse than no map at all — it creates false confidence and leads to wrong decisions.

The skills in this section — how to set up a drawing, use scales, plot angles and distances, and preserve the finished product — are straightforward but require care. A surveyor who takes pride in clear, accurate drafting produces work that serves the community for generations.

Materials for Drafting

Paper: The best drafting paper is flat, smooth, and resistant to tearing when erasing. Vellum (thin, translucent parchment or its manufactured equivalent) is excellent because copies can be made by tracing. Heavy, smooth cotton paper is durable. Rough or absorbent paper makes drawing accurate lines difficult.

If manufactured paper is not available, prepare sheets of scraped and smoothed animal skin (vellum), or press and dry smooth sheets from plant fiber. The surface must not absorb ink immediately (allow drawing corrections) but must hold ink when dry.

Drawing instruments:

• Compass: For drawing circles and transferring distances. Can be improvised from two sticks with a fixed pivot and a point at one end.
• Straightedge: For ruling straight lines. A flat piece of straight-grained wood or a piece of stone with a straight edge.
• Protractor: For measuring and laying off angles. Half-circle marked in degrees. Can be made by carefully dividing a semicircle. Accuracy depends on the care taken.
• Scale ruler: A straightedge with distances marked at the drawing scale. Allows reading distances directly from the map without calculation.
• Drawing pen: Any tool that makes a fine, consistent line. Sharpened charcoal, a cut quill, a fine-pointed bone stylus with ink.

Ink: Carbon-based inks (lamp black or charcoal mixed with a binder) are the most permanent. Iron-gall ink made from oak galls was the standard for European documents for a thousand years and remains readable today. Avoid inks that fade (berry dyes) or that remain soluble (powdered pigments without a fixing agent).

Map Scale

Scale is the ratio of map distance to ground distance. A scale of 1:500 means 1 cm on the map represents 500 cm (5 m) on the ground. A scale of 1:1000 means 1 cm represents 10 m.

Choosing scale: Larger scale (smaller ratio denominator) shows more detail but covers less area per sheet. Smaller scale shows less detail but covers more area.

Scale	1 cm represents	Use
1:100	1 m	Building interior layout
1:200	2 m	Building site layout
1:500	5 m	Farm layout, road design
1:1000	10 m	Village or small farm area
1:5000	50 m	Township or large estate
1:10000	100 m	Regional overview

Scale bar: Every map must include a graphical scale bar — a line divided into measured units at the map scale. The scale bar allows the map to be used correctly even if the paper shrinks, expands, or is reproduced at a different size. Do not rely on “scale 1:500” text alone — verify against the graphical bar.

Scale calculation: To convert ground distance to map distance, divide by the scale denominator. A 47.3 m fence line at 1:500 scale = 47.3 / 500 = 0.0946 m = 9.46 cm on the map.

To convert map distance to ground distance, multiply by the scale denominator. A 7.3 cm line on a 1:1000 map = 7.3 × 1000 = 7300 cm = 73 m on the ground.

Plotting a Traverse

A traverse (series of connected lines) is the most common survey result to plot.

Method 1: Coordinate plotting If you have computed the coordinates (northing and easting) of each traverse station, plot them directly on a grid.

1. Draw a grid on your paper with north-south and east-west lines at regular intervals matching your scale.
2. Plot each station at its computed coordinate position.
3. Connect stations in order with straight lines.
4. Check: the drawn boundaries should match what you observed in the field.

Method 2: Bearing and distance plotting (with protractor) If you have only raw field data (bearing and distance for each leg), plot step by step.

1. Draw a north reference line at your starting point.
2. Using a protractor centered at the starting point, lay off the first bearing angle from north.
3. Along this direction, measure the first leg distance at your chosen scale. This places the second station.
4. Draw a north reference line at the second station (parallel to the first).
5. Lay off the second bearing and distance to find the third station.
6. Continue around the traverse.

If the traverse is closed, the last plotted point should fall exactly on the first point. Any gap is the graphical closure error and should be consistent with the calculated misclosure.

Method 3: Coordinate protractor Draw a circle on your starting point. Mark all 360° around it. Draw rays from the center at the bearing angles. Mark distances along each ray. This gives a graphical layout of the survey without computing rectangular coordinates.

Drawing Conventions

Consistent drawing conventions allow anyone familiar with surveying maps to read yours correctly.

North arrow: Every map must have a north arrow, clearly marked, indicating the orientation of the sheet. Note whether north is true north or magnetic north, and the date of the magnetic observation if magnetic.

Title block: In a corner of the map (typically lower right), include:

• Map title and subject
• Location (enough to identify on a larger map)
• Scale (graphical scale bar and ratio)
• Date of survey
• Name of surveyor
• Sheet number if multiple sheets

Line weights: Use heavier lines for important features (boundary lines, building outlines) and lighter lines for secondary features (fence lines, vegetation boundaries). Consistency helps the map reader interpret relative importance.

Symbols: Develop a consistent symbol set and include a legend on each map. Common conventions:

• Solid heavy line: property boundary
• Dashed line: approximate boundary or underground feature
• Cross-hatching: buildings and structures
• Dotted line: paths and informal tracks
• Wavy line: water features
• Small circles: trees

Elevation markings: Spot heights are shown as a point with the elevation written beside it. Contour lines are drawn with every fifth line (index contour) heavier and labeled with elevation.

Maintaining Survey Records

Original field books: Store in a dry location, protected from light and insects. Do not use them as scratch pads after the survey. If possible, make a copy of the field book by transcription before using the original in another field session — if the original is lost in the field, the copy survives.

Finished maps: Mount on rigid backing if they will be frequently handled. Store flat, not rolled (rolling induces creases that make subsequent reference difficult). Protect from moisture with a waterproof folder or container.

Index: Maintain a written index of all surveys: date, location, surveyor, subject, and where the original records are stored. Without an index, records become impossible to find as the collection grows.

Datum and reference records: Record the location and elevation of all benchmarks, and the coordinates of all primary control points, in a permanent register separate from individual survey records. These are the master reference documents that tie all subsequent surveys together.

The Duplicate Rule

Keep at least two copies of every completed map and every field book, stored in different locations. One disaster — a fire, a flood, a break-in — should not be able to destroy your community’s entire survey record. The duplication cost is low; the replacement cost is enormous.