maanantai 3. syyskuuta 2012


In the right hand side bar of my blog there has always been a little image telling the number of geocaches I have found. Also, in the very first post of this blog I mentioned that you might see an occasional post about geocaching, but that hasn't really been true -- until now.

A particularly clever cache, drilled into a tree stump and openable with a key. (The code that identifies the cache has been blurred.)
I think geocaching is a pretty well known hobby already, but still not all people have heard about it yet. It's basically a modern game of treasure hunt: someone hides a container, a geocache, somewhere and posts the coordinates on the Internet, and then other people go and find it. You usually use a GPS device to find the cache, but often just a map is enough. Most if not all smartphones already have a GPS receiver built-in, so basically you probably don't even need to buy any new equipment to start the hobby. I've been caching just fine with my phones for some three years now. :)

Okay, so what's a geocache like, you may ask? Well. Probably the only common denominator with all caches is that they all contain a log book. It's either a real book or a dedicated piece of paper where you sign your nickname. Afterwards you go online to and log your find to the cache's own page as well.

OK, but what's a geocache really like, then? One of the most common appearances is a plastic box of a couple of deciliters. Film canisters are also popular. The tiniest caches I have found are nano-caches that measure less than 2 by 2 by 2 cm, such as this one, and the largest has been a plastic container of about 40 liters. Needless to say, the first one can be hidden in the busiest place of a city center, whereas the latter definitely needs a remote place in the woods.
One of the weird things I've seen while caching: a tree had grown up right through a fence.

Right, so where are these geocaches hidden? I already touched this subject in my previous sentence, and the answer is that they can be hidden basically anywhere: in the cities or in the woods, in parks, mountains, bus stops, train stations, light poles, stone walls. In cities you can often find micro-caches under, behind and inside various pipes, bars and railings. They may be under staircases or in a bush. They may be hanging from trees or they may be hidden in the roots of a tree, behind some stones.

OK, but what's so interesting about finding a plastic box from the woods? Well, usually the cache page contains a description of the place: why does the cache owner want to show you the place? There are, of course, those boring boxes with no purpose as well, but you don't need to get those. :) Geocaching is a great way to get to know a new city, for example. Geocaching takes you outside the normal tourist areas and attractions and shows you less-known and quaint places. For example here in Helsinki, Finland there are many World War I era fortifications in the forests and many caches have been placed in them. In London there was a cache in front of two houses – which are actually fake, designed to hide a railroad. Normally you'd just pass this kind of a place without noticing anything, but with geocaching you become familiar with the local history.

Traditional cache
Besides the location, the cache itself might be interesting and worth seeing in its own. Some cache owners put a lot of time and effort to construct contraptions where you have to, for example, open some lid with a key or winch a container down from a tree. I have seen a cache camouflaged as a beehive, and some of the funniest caches are the ones that are hidden in plain sight, disguised as electric boxes or some such ordinary objects that just belong to the landscape.

Besides the traditional caches where someone just posts the coordinates on the Internet and you go find it, there are other kinds of caches as well. The most popular other types are multi-caches and unknown caches, also known as puzzle or mystery caches. Multi-caches contain one or more intermediate points before the final location where the cache with the log book is. In the intermediate locations you might find cache boxes with coordinates, or you might have to calculate, say, the number of windows in a building and apply that number to a formula given in the cache description to get the next coordinates. Multi-caches may be of any length: 20 meters, 2 kilometers or 200 kilometers. The basic rule with all caches, though, is that there must be at least 161 meters, or 0.1 miles, between them.

Mystery cache
Finally, mystery caches can be pretty much like anything. There might be a simple jigsaw puzzle that you must build in order to see the coordinates in the picture that forms, or the puzzle might require deep knowledge of some sports league, programming language or historical event or person.

A screenshot from, showing you the strategic information of the Oslo Concert Hall cache: D/T 2/1.5, small.
Oh, and how do you know which caches would be easy and which ones would be difficult? All the caches have two ratings assigned to them by the author: the difficulty rating (D) and the terrain rating (T). You seldom see traditional caches with difficulty values over D3 or D3.5, and those are often used by cleverly camouflaged caches or caches in places with many possible hiding places. A cache with a difficulty rating of D1 should be quite trivial to find, whereas a mystery cache with a difficulty rating of D5 might stay unsolved for weeks or months. Difficulty ratings are, however, quite subjective. In the end terrain ratings are also subjective, but I think they are less subjective than difficulty ratings anyway. A T1 cache can usually be retrieved even from a wheelchair, whereas a T5 cache basically requires you to have some special equipment, such as climbing gear, or you will risk serious injury or even death. Of course one of the fun parts of the hobby is that there's something for everyone and you can only go find those caches that suit your tastes and skills. :)

So, what are you waiting for? Go check out the map of geocaches in your area, register to the site, get the coordinates and go out with your smartphone. :)