The GPS is a wonderful and very powerful navigational tool. It works so well, in fact, that it enables people to find their way without doing any real navigation. We wondered how many geocachers really know how to navigate. This cache was created to test your understanding of some basic principles of navigation. If you understand them and are careful, this cache will be a no brainer.
To do the cache you will need a compass and GPS at a minimum. Read the instructions before leaving home and think through how you will determine the cache location. If your are unsure what you must do, check the hint and make sure you are familiar with the terms it contains. A little homework might be required for some. If you're still unsure how to proceed, check our profile for helpful information. For reasons that will soon become obvious, this cache should be attempted on a clear day. The cache is a large ammo can hidden within a few feet of a path on public land. No bushwacking is required.
The above coordinates are to a trail junction in a small park. You will need to determine several compass bearings and use them to calculate the location of the next waypoint. To minimize problems caused by slight errors in measurement, I have supplied a list of the readings I obtained along with some erroneous ones. For the calculations, use values from the following list that most closely match the readings you obtain:
8, 26, 46, 74, 92, 110, 190, 208, 226, 254, 272, 290, 350
First, locate the following objects you will use to determine the necessary bearings.
1) A round observation tower arising from a house right next to the park.
2) A benchmark disk. To find it, face Mt. Hood from the junction. Across the park are some shrubs directly in line with Mt. Hood. The disk is attached to the top of a large rock on the far side of the shrubs.
3) A park bench.
4) A trash can (next to the bench).
5) A large, white church building. To find it, sit on the bench and look just over the roof of the house that is right in front of you. You will see the roof of a large white building with 4 pointed towers arising from its corners. It's a bit over a mile away.
6) Mt. Hood
7) Mt. Saint Helens
Next, record the following compass bearings.
A = True bearing from junction to Mt. St. Helens
B = True bearing to the benchmark disk from the park bench
C = True bearing from white building to the park bench
D = Magnetic bearing from trash can to observation tower
E = Magnetic bearing from Mt. Hood to the junction
F = Magnetic bearing to the white building from the bench
To determine the location of the final waypoint relative to your current position, solve the following algebraic equations. (30A means 30 times A)
Y (in meters) = 30A + 10B + 20C – 1753
X (in meters) = 20D + 10E + 10F - 1631
The next waypoint is Y meters north and X meters east of the trail junction.
When you arrive at the final waypoint, you will be on a path where it crosses an intermittent stream. Move south a few feet along the path until you are standing on a concrete slab. The cache is
in a large hollow stump only a few feet from the path and less than 100 yards away. The exact bearing from the cache to your present location is 135 degrees True. The hiding place is very conspicuous. It should not be necessary to trample any vegetation to find the cache.
HELP - Verify your calculations using the following check sums. To get the check sum, add all the digits of your answer together. For example, to the find checksum for the value 461, add 4 + 6 + 1 which equals 11.
The checksum for X is 17.
The checksum for Y is 21.