Cartography & Surveying

Why This Matters

A community without a map is a community that does not know what it has. You cannot plan trade routes if you do not know where the other communities are. You cannot allocate farmland fairly if you have not measured it. You cannot defend a territory whose boundaries are not defined. You cannot find resources you have not recorded. Cartography — the art of making maps — and surveying — the science of measuring the land — are how a community transforms vague knowledge into precise, shareable, permanent information. A good map is worth more than a hundred verbal descriptions.

---

What You Need

Essential Materials

• Flat drawing surface — paper, birch bark, scraped hide, smoothed wood, or cloth. Paper is ideal but anything flat and durable works.
• Writing/drawing tools — pencils, charcoal sticks, ink and quills, or sharpened sticks dipped in soot-and-water ink.
• Straight edge — a flat stick or board with a true straight edge. Test by drawing a line, flipping the edge, and drawing another — they should be parallel.
• Cord or rope — for measuring distances. At least 30 meters. Braided cord stretches less than twisted rope.
• Measuring rod — your community’s standard length unit (see Trade & Currency for establishing standards). About 1 meter long with 10 subdivisions marked.
• Stakes or poles — sharpened wooden stakes for marking points in the ground. At least 20, 30-60 cm long.
• A magnetic compass — salvaged or hand-built (instructions below).
• A sighting device — a straight tube, a pair of nails on a board, or a hand-built transit (instructions below).
• A plumb line — a weight on a string. Any heavy small object (stone, metal nut) tied to thin cord.
• A level — a straight board with a plumb line hanging from its center, or a water level (a tube partially filled with water).

Optional but Useful

• Binoculars or telescope — for sighting distant landmarks
• Protractor — for measuring angles on paper (can be hand-made)
• Grid paper — makes drawing to scale much easier (can be hand-ruled)

---

Building a Compass

If you do not have a magnetic compass, you can make one. You need a magnetized needle.

Step 1: Magnetize a Needle

1. Find a steel needle, pin, or thin piece of steel wire (a straightened paper clip works).
2. Method A — Using a magnet: Stroke the needle with a magnet, always in the same direction (not back and forth), 50-100 times. This aligns the magnetic domains in the steel.
3. Method B — Using a battery and wire: Wrap insulated copper wire around the needle 50-100 times in a tight coil. Connect the wire ends briefly to a battery (car battery, flashlight batteries). The electrical current through the coil magnetizes the needle. Disconnect after 30-60 seconds.
4. Method C — Using silk or wool: Stroke the needle rapidly in one direction against silk or wool. This is the weakest method but works in a pinch.

Step 2: Build the Compass

Floating compass (simplest):

1. Fill a small container (cup, bowl, half coconut) with still water
2. Place a small leaf or thin piece of cork on the water surface
3. Gently lay the magnetized needle on the leaf/cork
4. The needle will slowly rotate until it points north-south
5. The end that was at the START of your magnet strokes points north

Pivot compass (more practical for field use):

1. Find or carve a small post with a sharp point (a nail sticking up from a wooden base)
2. Balance the magnetized needle on the point — it needs a tiny dimple drilled in its center to sit on the point without falling
3. The needle will swing freely and settle pointing north-south
4. Mark the base with N-S-E-W directions

Step 3: Verify Your Compass

Check it against known direction-finding methods:

• At night, find Polaris (North Star) — it should align with your compass’s north
• At solar noon (when the sun is highest), your shadow points due north (in the Northern Hemisphere) or due south (in the Southern Hemisphere)
• If compass and stars disagree, the compass may be affected by nearby iron or steel. Move away from metal objects and re-test.

---

Method 1: Pace-and-Compass Survey

This is the simplest surveying method and works for mapping areas up to several square kilometers. It is how most historical maps were made before precision instruments.

Step 1: Calibrate Your Pace

Your pace (one double step — left foot to next left foot) is your basic distance unit in the field.

1. Lay out a measured distance on flat ground using your measuring rod. 50 meters is ideal.
2. Walk the distance at your normal walking speed, counting paces.
3. Repeat 5 times and average the results.
4. Calculate: pace length = 50 meters / average pace count
5. Example: If you average 33 paces over 50 meters, your pace = 1.52 meters.
6. Write this number down and keep it with your surveying kit.

Tip

On slopes, your pace shortens. Going uphill, subtract about 10% from your flat-ground pace length. Going downhill, subtract about 5%. On very rough terrain, subtract 15-20%.

Step 2: Set Up Your Survey

Choose a starting point that is prominent and easy to return to — a large tree, a rock outcropping, a building corner. Drive a stake and mark it as “Station 1.”

Equipment check:

• Compass in hand
• Notebook and writing tool
• Stakes in a bag or bundle
• Measuring rod (for short, precise measurements)

Step 3: Walk and Record

From Station 1, choose a direction to your next point of interest (a boundary marker, a resource location, a trail junction, a water source).

1. Take a compass bearing. Hold the compass level, sight along the direction you want to walk, and read the angle from north. Record it in your notebook: “Station 1 to Station 2: bearing 047 degrees.”
2. Walk to the next point, counting paces. Walk as straight as possible. Sight a landmark on your bearing and walk toward it.
3. Record the distance. “Station 1 to Station 2: bearing 047, 85 paces (= 129 meters).”
4. Drive a stake at Station 2.
5. Note features. Record anything important near each station: “Station 2: junction of creek and east trail, large oak tree, freshwater spring 15 paces north.”
6. Repeat. From Station 2, take a bearing and pace count to Station 3, and so on.

Step 4: Handle Obstacles

You will encounter things you cannot walk straight through — ponds, cliffs, dense vegetation.

To bypass an obstacle:

1. At the obstacle’s edge, turn 90 degrees to your original bearing
2. Walk and count paces along this perpendicular line until you clear the obstacle
3. Turn back to your original bearing and continue walking
4. When you are past the obstacle, turn 90 degrees back and walk the same number of paces as step 2
5. You are now back on your original line. Continue pacing.

Record everything: “Detour at 42 paces: turned 90 degrees left, walked 15 paces, resumed bearing, walked 30 paces past obstacle, turned 90 degrees right, walked 15 paces to return to line.”

Step 5: Close the Loop

For area mapping (like mapping your community’s territory), walk a complete loop back to Station 1. The endpoint should fall exactly on Station 1.

If it does not (and it will not, because of accumulated errors), measure the gap between where you ended up and where Station 1 actually is. This is your closure error.

• Acceptable closure error: Less than 1 in 50 (if your total loop was 1000 paces, being off by less than 20 paces is acceptable for community mapping).
• If error is too large: The most likely cause is a wrong compass bearing or a miscount. Resurvey the most suspect leg.

---

Method 2: Building a Simple Transit/Level

A transit lets you measure horizontal and vertical angles precisely. A level tells you whether two points are at the same elevation. Combined, they enable accurate surveying for construction, irrigation, and boundary marking.

Building a Water Level

The simplest and most reliable leveling tool.

1. Get a clear or translucent flexible tube, 5-10 meters long. Garden hose works but clear vinyl tubing is better because you can see the water.
2. Fill the tube with water, leaving about 30 cm of air at each end. Remove all air bubbles — they cause errors. Tilt and tap the tube to work bubbles out.
3. How it works: Water seeks its own level. When you hold both ends of the tube upright, the water surface in each end is at exactly the same height, regardless of terrain between them.
4. To use: One person holds one end of the tube against a reference point (a stake at known height). Another person holds the other end at the point being checked. When the water level at the reference end is at the mark, the water level at the other end shows the exact same elevation.
5. Mark the matching height on the far stake. You now know both points are at the same elevation.

Accuracy: A water level is accurate to within about 3 mm over 10 meters — more than adequate for any surveying task in a rebuilding community.

Building a Simple Transit

A transit measures horizontal angles (for bearings) and vertical angles (for elevation differences).

1. Base: A flat wooden board, approximately 30 cm square, mounted on a tripod or on top of a vertical stake driven firmly into the ground.
2. Degree circle: Draw a large circle on the board (as large as the board allows). Divide it into 360 degrees. This requires patience:
   • Draw the circle with a compass (the geometric kind — a stick with a pivot and a drawing point)
   • Mark 0/360 at the top (north)
   • Divide into quarters (0, 90, 180, 270) using perpendicular lines
   • Divide each quarter into 9 equal parts (every 10 degrees)
   • Subdivide further if your drawing skills allow (every 5 degrees is adequate for community surveying)
3. Sighting arm (alidade): A straight, flat piece of wood or metal as long as the circle’s diameter. Mount it at the center of the circle with a nail or bolt so it pivots freely. Place two upright sighting pins (nails) at each end of the arm, exactly the same height.
4. Level the base: Use a plumb line or water level to ensure the board is perfectly horizontal before taking readings.
5. To take a bearing: Align the sighting arm so that both pins line up with your target. Read the angle where the arm crosses the degree circle. That is the bearing.
6. To measure vertical angles: Mount a second degree circle vertically on the sighting arm, with a plumb line hanging from its center. When you tilt the arm to sight uphill or downhill, the plumb line hangs straight down and the angle between the arm and the plumb line is the vertical angle.

---

Method 3: Drawing a Community Map

With survey data in hand, you can create an accurate map.

Step 1: Choose Your Scale

Scale is the ratio between distances on the map and distances on the ground.

• For a community area (1-5 km across): 1:5,000 works well. 1 cm on the map = 50 meters on the ground.
• For a larger region (10-50 km): 1:50,000. 1 cm = 500 meters.
• For a building or small area: 1:100. 1 cm = 1 meter.

Write the scale on the map. Always.

Step 2: Establish the Map Framework

1. Orient the map. North is at the top. Draw a north arrow in the upper right corner.
2. Plot Station 1 near the center of your drawing surface (so the map can extend in all directions).
3. Plot subsequent stations:
   • Use a protractor (or your transit’s degree circle) to mark the bearing angle from each station
   • Calculate the map distance: ground distance / scale factor. Example: 129 meters at 1:5,000 scale = 129/5000 = 0.0258 meters = 2.58 cm on the map.
   • Mark the point and label it with the station number
4. Connect stations with lines. These form the skeleton of your map.

Step 3: Add Features

Using your field notes, add details around each station:

Standard mapping symbols (establish these for your community and use them consistently):

Feature	Symbol
Building	Small filled rectangle
Water source (spring, well)	Small circle with a dot in the center
River/stream	Wavy line (width proportional to water body)
Road/trail	Double parallel lines (solid for road, dashed for trail)
Forest/dense vegetation	Small circles clustered together
Farmland	Crossed diagonal lines
Elevation point	Dot with number (height above a reference point)
Community boundary	Dash-dot line
Bridge	Double line crossing water with cross marks
Dangerous area	Small triangle with exclamation mark

Step 4: Add Map Elements

Every useful map must have:

1. Title — “Map of [community name] territory” with the date of survey
2. North arrow — always at the top
3. Scale bar — a line drawn at the correct length with distance labels (e.g., a 2 cm line labeled “100 meters”). Better than a ratio because the scale bar remains accurate even if the map is copied at a different size.
4. Legend — a box explaining every symbol used on the map
5. Date — when the survey was done
6. Surveyor’s name — who made this map (for accountability and questions)

Step 5: Terrain Representation

Showing elevation (hills, valleys, slopes) on a flat map requires one of these techniques:

Contour lines (best method):

1. A contour line connects all points at the same elevation
2. Choose a contour interval (the elevation difference between lines). For hilly terrain, 10 meters works. For flat terrain, 2-5 meters.
3. Using your level and transit, identify points at the same elevation and mark them on the map
4. Connect the points with smooth curves
5. Closely spaced contours = steep slope. Widely spaced = gentle slope.
6. Label every 5th contour line with its elevation

Hachure marks (simpler):

1. Draw short parallel lines pointing downhill
2. Steeper slopes get more closely spaced marks
3. Less precise than contours but faster and requires less surveying data

---

Triangulation

Triangulation lets you locate distant points without walking to them — essential for mapping features on the far side of a river, across a canyon, or on a hostile territory.

The Principle

If you know the length of one side of a triangle and the angles at both ends of that side, you can calculate the position of the opposite point.

How to Do It

1. Establish a baseline. Measure a straight distance between two known points (Station A and Station B) as accurately as possible. This is the ONE measurement you need to be very precise about. Use your measuring rod, not paces.
2. From Station A: Sight the target point (the distant feature you want to locate) using your transit. Record the angle between the baseline and the sighting line.
3. From Station B: Sight the same target point. Record the angle between the baseline and the sighting line.
4. On paper: Draw the baseline at scale. Using a protractor, draw lines from each end of the baseline at the recorded angles. Where the lines intersect is the target point’s position.

Example:

• Baseline AB = 200 meters, running east-west
• From A, the target is at 35 degrees from the baseline
• From B, the target is at 110 degrees from the baseline
• Draw this on paper at scale. The intersection is the target’s position. Measure the distance from the baseline to the intersection on paper, multiply by the scale factor, and you have the distance to the target.

Extending a Triangulation Network

Once you have located one distant point by triangulation, you can use it as a station for further triangulation. This lets you map an entire region from a small number of precisely measured baselines.

1. From your first triangle, you now have three known points (A, B, and the target C)
2. Use any two of these as a new baseline
3. Sight a new distant point D from two of the known stations
4. Repeat, extending the network further

This is how entire countries were mapped before GPS existed.

---

Resource Mapping

One of the most practical applications of cartography: recording where useful resources are located.

What to Map

• Water sources: Springs, wells, streams, rivers, ponds. Note whether seasonal or permanent, flow rate if estimated, water quality.
• Arable land: Soil quality (dark, rich soil vs. sandy or rocky), slope, drainage, sun exposure.
• Forests: Wood type (hardwood, softwood), density, accessibility.
• Mineral deposits: Clay beds, stone quarries, sand deposits, metal-bearing rock (look for rust-colored streaks in stone).
• Medicinal plants: Locations of useful plant populations.
• Wildlife: Migration routes, nesting areas, fishing spots.
• Hazards: Flood zones, unstable slopes, contaminated areas, dangerous wildlife territories.
• Salvage sites: Abandoned buildings, vehicles, factories, stores with useful materials.

Create a separate map layer (or separate map) for resources, using your base map as the foundation. Update it regularly as resources are discovered, depleted, or change seasonally.

---

Boundary Marking

Clear, agreed-upon boundaries prevent land disputes — one of the most common sources of conflict in any community.

Physical Boundary Markers

1. Cairns — piles of stones at boundary corners and along boundary lines. Build them 1-1.5 meters tall, wide enough to be stable. Place them at every corner and at intervals along straight boundary sections (every 100-200 meters).
2. Blazed trees — if boundaries run through forest, mark trees on the boundary line by cutting a distinctive mark into the bark. Three horizontal cuts is a traditional boundary mark.
3. Ditches or berms — a shallow ditch or low earth mound along the boundary is visible and long-lasting. Useful for property boundaries between farms.
4. Engraved stones — flat stones with carved marks placed at boundary corners. Durable and unmistakable.

Documentary Boundaries

Physical markers can be moved, destroyed, or buried. Always supplement them with:

1. Written description referencing permanent features: “From the large oak at the creek bend, 150 paces northeast to the stone outcropping, then 200 paces east to the lone pine…”
2. Map with boundary plotted — a copy held by each neighboring party and by the council
3. Witness signatures — both parties and at least two witnesses sign the boundary agreement

---

Common Mistakes

Mistake	Why It’s Dangerous	What to Do Instead
No scale on the map	Distances cannot be determined; the map is just a picture	Always include a scale bar and state the ratio
Not calibrating your pace	Distance measurements can be off by 20-30%	Calibrate on measured ground; recalibrate for different terrain
Compass near metal objects	Readings are deflected; entire survey is wrong	Keep compass at least 2 meters from iron, steel, or electronics
Not closing survey loops	Errors accumulate without detection; map drifts from reality	Always close your loop back to the starting point and check closure error
Only one copy of the map	Fire, water, or damage destroys your only record	Make at least 2 copies; store in separate locations
No north arrow	Nobody knows which direction the map is oriented	Always mark north. Always.
Inconsistent symbols	Different people interpret the map differently; confusion	Establish a standard legend and use it on every map
Boundary markers with no written backup	Markers can be moved, stolen, or destroyed	Always supplement physical markers with written descriptions and maps
Surveying in bad weather	Rain obscures sighting targets; wind affects plumb lines; wet notebooks are ruined	Survey on clear, calm days; protect your notes
Not recording the survey date	Maps become outdated; nobody knows how old the data is	Date every map and every page of field notes

---

What’s Next

With surveying and mapping skills, your community can support more sophisticated infrastructure and trade:

• Next step: Trade & Currency — mapped trade routes and measured land boundaries enable commerce and fair property allocation
• Builds on: Navigation — compass skills and direction-finding are prerequisites for surveying
• Builds on: Writing & Record Keeping — all survey data must be recorded systematically
• Related: Community Organization — boundary marking and resource mapping support governance decisions
• Enables: Infrastructure planning — every bridge, road, irrigation channel, and building starts with a survey

---

Quick Reference Card

Cartography & Surveying — At a Glance

Building a compass:

1. Magnetize a needle (stroke with magnet 50-100 times in one direction)
2. Float on a leaf in still water, or balance on a pivot point
3. Verify against Polaris or solar noon shadow

Pace-and-compass survey:

1. Calibrate your pace on measured ground (50m, 5 trials, average)
2. Start at a marked station with compass and notebook
3. At each leg: record bearing (degrees), count paces, note features
4. Drive a stake at each station
5. Close the loop; check closure error (acceptable: less than 1 in 50)

Drawing a map:

1. Choose scale (1:5,000 for community area)
2. Plot stations using bearing + scaled distance
3. Add features using consistent symbols
4. Always include: title, north arrow, scale bar, legend, date, surveyor name

Triangulation:

1. Measure a precise baseline between two known points
2. From each end, sight the target and record the angle
3. On paper, draw baseline at scale, plot angles, find intersection

Every map must have:

• Title and date
• North arrow
• Scale bar
• Legend
• Surveyor’s name

Boundary marking: Physical markers (cairns, blazed trees, engraved stones) + written description + map + witness signatures