Coordinate Puzzle Types
Coordinate puzzles can take many forms:
- Projection puzzles — Calculate a new point from bearing and distance
- Averaging puzzles — Find the centroid of multiple waypoints
- Format puzzles — Convert between DD, DDM, DMS, UTM, etc.
- Formula puzzles — Substitute values into coordinate templates
- Triangulation puzzles — Use distances from known points
1. Waypoint Projection Puzzles
Give solvers a starting point, bearing, and distance to calculate the final location.
Example puzzle:
Start at N 51° 30.000 W 000° 07.500
Project 137 metres at bearing 045° (NE)
That's your cache location.
Making It Interesting
- Hide the bearing: "Face the church spire and walk 50m"
- Calculate the distance: Use word values or field counts for metres
- Multiple projections: Chain 2-3 projections together
- Cardinal puzzles: "Go NORTH + SOUTH + EAST" where words encode distances
2. Coordinate Averaging Puzzles
Give multiple waypoints and ask solvers to find their centre point (centroid).
Example puzzle:
Visit these three historic landmarks:
N 51° 30.123 W 000° 07.456
N 51° 30.789 W 000° 07.012
N 51° 30.456 W 000° 07.890
The cache is at the centre of this triangle.
Creative Applications
- Themed waypoints: "Find the centre of these 5 pubs"
- Historical research: Waypoints require research to find
- Field collection: "Record 4 coordinates and average them"
- Weighted averages: Some points count more than others
3. Format Conversion Puzzles
Present coordinates in unusual formats that require conversion.
Degrees Decimal (DD)
51.50000, -0.12500
Degrees Decimal Minutes (DDM)
N 51° 30.000 W 000° 07.500
Degrees Minutes Seconds (DMS)
51° 30' 00" N, 0° 7' 30" W
UTM
30U 699375 5710163
Plus Codes
9C3XGW4F+5V
What3Words
///filled.count.soap
Mix formats to add difficulty—give latitude in DMS and longitude in decimal degrees.
Open Coordinate Converter4. Formula Coordinate Puzzles
The classic geocaching puzzle format—provide a coordinate template with variables.
Example formula:
N 51° AB.CDE
W 000° FG.HIJ
Where:
A = Number of windows on the church
B = First digit of the year on the plaque
C = Letters in the pub name
... and so on
Variable Sources
- Field counting: Windows, steps, benches, trees
- Research: Dates, heights, populations, distances
- Cipher decoding: A1Z26 values, word sums
- Mathematical: Prime factors, digital roots
- Trivia: Quiz answers converted to numbers
Difficulty Variations
Easy (D1-D1.5)
- • Simple projection with given bearing and distance
- • Average of 2-3 clearly stated waypoints
- • Single format conversion
Medium (D2-D2.5)
- • Bearing/distance require calculation or research
- • Multiple waypoints with research needed
- • Formula with 5-10 field variables
Hard (D3+)
- • Chained projections with cipher-encoded values
- • Triangulation from three distance hints
- • Complex formulas with interdependent variables
- • Multiple format conversions in series
Complete Example Puzzle
Cache Title: "The Compass Rose"
Cache description:
"Start at the village war memorial: N 51° 30.000 W 000° 07.500
From there, project towards the direction of the setting sun at midsummer (bearing 304°). Walk the number of metres equal to the sum of the digits on the memorial's foundation date.
The memorial was dedicated in 1923."
Solution:
Distance = 1 + 9 + 2 + 3 = 15 metres
Bearing = 304° (given)
Project 15m at 304° from N 51° 30.000 W 000° 07.500
Final: N 51° 30.007 W 000° 07.513
Pro Tips
- Test in the field. Walk to your calculated final to confirm it's a valid, safe, accessible cache location.
- Account for GPS accuracy. Don't place the cache exactly at computed coordinates—leave a few metres margin for GPS drift.
- Provide a checker. Use GeoChecker or similar to let solvers verify coordinates before travelling.
- Consider seasonal access. Field-based puzzles may be inaccessible in certain seasons (overgrown, flooded, etc.).