Apply offsets to coordinates (usually associated with puzzles or mysteries)

[+knhdah]

Hi there, I'm wondering if there's a quick/easy way to apply offsets to coordinates? I've run across several mystery caches where the original coordinates will have a plaque or something to grab additional numbers from. Then after you add them together, you're to apply the additional numbers to the original coordinates as offsets. Is it just a matter of converting the feet to a decimal and adding or subtracting it from the original, or is there some complex mathematical formula?

 

For example, a cache near me said to add up all the digits from a sign, which then became XX. Now project a waypoint XX feet north from where you are standing and proceed to that point, where you should be able to locate the container. Note: this scenario is from a real cache, but the coordinates are made up so as to not jeopardize the integrity of the puzzle. And I was able to solve that one with help from the Cache Owner who gave me a huge hint without an offset lesson, so I'm really just asking for going forward. So if the coordinates were N 45 37.013 and XX was 20, what should have the new coordinates been?

 

Thanks in advance ~Kristin

[+ramblingduck]

Various GPS units have project waypoint functions where you enter the compass bearing (0 degrees in your example) and distance from your current location. For my unit, the Oregon 600, you mark a waypoint and then go into the options and select project waypoint.

 

Another is to have your GPS set to display the distance and bearing to the current waypoint, then simply walk away from the point until the unit reads the offset distance and the bearing shows the correct back-bearing or 180 degree difference from the offset bearing. If the cache is located at a bearing of 0 degrees from the original waypoint, then the original waypoint is located at a backbearing of 180 degrees from the cache location.