In Geocaching there is a type of cache called a “Multi”, or “Multi-Cache”. It requires the user to locate an initial cache that provides directions to the next cache, which when found provides directions to another cache, and so-on until the final cache is found. My initial thoughts to these type of caches were that they are like the old fictional pirate treasure maps.
I’m sure you’ll recognize the following excerpt from a popular 80’s movie:
Mikey pulls out the doubloon and verifies another critical alignment.
Mikey: Guys...I think I have a match. I'm sure of it! The lighthouse, the rock, and the restaurant all fit the doubloon. That must mean that the rich stuff is near the restaurant. So, (pulls the map out of his shirt), wait a second, Mouth, I'm going to need you to translate the map because I don't understand Spanish. (Pointing) Right here.
Mouth: (Looking at the map) Alright, alright, alright. (Reading) (spanish)
Mikey: What does that mean?
Mouth: Ten times ten.
Mikey: Uh, hundred.
Mouth: (Translating) ...stretching feet to nearest northern point.
Mikey: North. What's north? Which way is north?
Mouth: That's where you'll find the treat.
Mikey: The treat...the rich stuff! The treat! The rich stuff. That's it!
Data: (Checks his compass and points) North is that way.
Now you can fulfill your childhood fantasies of joining Mikey’s gang in search for magical pirate treasure right from the convenience of this page.
I first attempted to create this calculator five years ago. My understanding of spherical coordinates was very limited – it still is – but I cracked open some websites and learned quite a bit. The trigonometry I did so well in during my time in High School was rusty, but I remembered enough that it was helpful.
It turns out this calculator was already placed up on NASA’s website a couple of years ago, though I’m not sure what algorithm they use. When doing research on that, I came across one of Wolfram Research’s pages on Spherical Trigonometry. Ah! Good head-spinning stuff… pun intended.
Here’s what to enter:
- Distance (Feet) = the distance from the center point in feet. If you’re interested in metric entry and results, post a comment.
- Heading (Compass Degrees) = the heading in compass degrees. 0 degrees is due North, 90 degrees is due East, 180 degrees is due South, and 270 degrees is due West.
- Latitude of Origin = coordinates in the format “N XX° YYY.ZZZZ'” where N denotes North/South from a drop-down, XX is the degrees and YYY.ZZZZ is the decimal minutes. This is the common form that Geocaching.com provides for coordinates.
- Longitude of Origin = the same as the Latitude, only for Longitude. It should now be able to handle W or E hemispheres to handle our friends on the other side of the meridian.
The Calculations are for nerds. The Results are for you. The coordinate results should display a link to Google maps when you’ve entered in all the criteria.
Update: 2017-06-15, I corrected the algorithm. Instead of using the angular distance, it uses a formula based on Haversine distance equation.
Have fun and post a comment to let me know if it’s useful.