Geocache Formulas

What it's for

Work out a geocache’s final coordinates. Multi-caches and puzzle caches often give the final position as a formula, such as N 51° 2A.B(C+1)D, where you find the letters’ values on the way. This fills them in, works out the brackets, reads the result as a position, and gives the digit sum that many checkers ask for.

For example, when you’ve found A to F at a multi-cache’s stages, type them in with the listing’s formula and copy the final position into your GPS.

How to use it

In Values, give each letter its number, as A=3 B=7 or one a line. A value can use earlier letters, as C = A + B.

In Formula, paste the formula from the listing. A letter on its own is replaced by its value, and anything in brackets is worked out first, with +, -, * (or x), /, ^ and the Calculator’s functions such as sqrt(…). The N or S at the start, and the E or W that starts the longitude, are read as compass letters rather than variables.

You get the filled-in formula, the position in degrees and minutes and in decimal degrees, its digit sum (with the north and east parts separately), and the value of each bracket. The message warns about a bracket that isn’t a whole number or is negative. The links open the position in a map or in the Coordinate Converter.

Example

Values:

A=3 B=7 C=1 D=4 E=5 F=4

Formula:

N 51° 2A.B(C+1)D W 000° 0E.(F*2)(A+4)B

It fills in as N 51° 23.724 W 000° 05.877, which is 51.395400, -0.097950 in decimal degrees, with a digit sum of 51 (north 24, east 27).

Good to know

A letter’s value is put in as all its digits, so if A is 12, 2A becomes 212: check the result has the right number of digits. Letters can only be single letters, and a variable named E or W written on its own after a space is read as a compass letter; write it in brackets, as (E), to use it as a variable there.

Use Number Codes (in Ciphers) to turn words into numbers first, for letter-value puzzles.