Adding and subtracting coordinates

[+joshenberg1]

I'm relatively new to Geocaching and I'd love to up my game by doing some multi caches! The problem is, I don't know how to add and subtract coordinates.

 

For example, One multi in my area asks you to find a plaque and then calculate the numbers on the plaque until you come up with two different numbers. It then asks the Geocacher to add the first number to the North coordinate and then deduct the second number from the west coordinate in order to come up with the coordinates of the next step.

 

Here's where the problem is. I don't know which digit in the original coordinates to add and subtract from. Do I add to the degrees, or do I add to the decimal? If I were to add to the decimal, which digit of the decimal would I add to?

 

The coordinates for this specific cache are: N 47 11.038" W 122 14.692"

 

Hopefully that makes sense. Thank you!

Edited May 19, 2017 by joshenberg1

[+Touchstone]

For most of the Multi's I've done that involve a sign and some math, the frame of reference has been the coordinates at the top of the page. Most of the time, the math only involves the last 3 digits of the North and the last 3 digits of the West. In your example, let's say you come up with a number of 12 from reading the plaque. If the instructions on the Listing page say to subtract that number from your North values, it would be 038-12 to give you a new coordinate of 026 for the last 3 digits of the North value.

 

Good luck!

[+noncentric]

Yep - most of the caches I've done have added to the full number of the listed coords. It can be more confusing when the number you're adding/subtracting pushes you into changing the number before the decimal.

 

Some examples, with entirely made-up numbers:

 

N 47 31.234 W 122 11.789

 

Add 451 to North & Subtract 451 from West = N 47 31.685 W 122 11.338

 

Add 810 to North & Subtract 810 from West = N 47 32.044 W 122 10.979

 

Add 1025 to North & Subtract 1025 from West = N 47 32.259 W 122 10.764

 

Hope that helps!

Edited May 20, 2017 by noncentric

[+HHL]

[...]

The coordinates for this specific cache are: N 47 11.038" W 122 14.692"

[...]

 

No. They are N 47° 11.038' W 122° 14.692'

Minutes are marked with a single quote. The quotes are marking seconds.

So this: W 122 14.692' (format: decimal minutes) - gives that: W122° 14 '41.52" (format: degree minute seconds)

 

Hans