If you want to know how to geocache properly then it's important to have a good understanding of how GPS co-ordinates work. This is especially useful when you are trying to solve puzzle caches.
Before we get going check out the photo on the right. I was geocaching near the Dead Sea in Jordan in November 2010. I thought it would be interesting to see what the GPS altitude would be the lowest point on earth. Look at the altitude... or whatever you call negative altitude.
BTW the geoaching app shown here is called Blackstar and works on Blackberries. Unfortunately my BB died after it got wet after I got back. Blackstar in conjunction with the GPS on the BB is such a good app that I hardly used Garmin.
Now that I have an Android, I'm back to the Garmin because the geocaching apps with the Samsung Galaxy GPS just don't work well enough for me. See my review on the Geoaching Android app here.
But I digress...
Understanding GPS Co-ordinates
To understand how to geocache you'll need to become familiar with how co-ordinates work.
Lines of latitude
We start by cutting the world in half horizontally - this line is called the equator.
Horizontal lines that circle the earth are called lines of latitude. Imagine that a line is drawn from the centre of the earth at angle to the horizontal. This angle gives us degrees latitude above or below the equator. So in the picture you can see N30, N50 N70 which are north of the equator, and S10, S30 which are south of the equator.
So if your latitude co-ordinate has an "N" in front of it, then you are north of the equator, and if it has an "S" in front of it you are south of the equator. Going back to the Dead Sea, you can can see that we are located at 31 degrees to the north of the equator. And at the north pole, we would be 90 degrees above the equator.
If, as you move, your latitude numbers increase, in the northern hemisphere you would be heading further north, and in the southern hemisphere you would be heading further south.
Lines of longitude
The line that cuts the world in half vertically through Greenwich in London is called the prime meridian - as you can see in the picture. Vertical lines that circle the earth are called lines of longitude.
Anything west of the prime meridian will have a "W" in the longitude, and anything to the east will have an "E" in the co-ordinate. Going back to the Dead Sea, you can can see that we are located at 35 degrees to the east of the prime meridian. If, as you move, your longitude numbers are increasing, and you have an "E" in front of your co-ordinate you would be heading further east, and if you have a "W" in the longitude, you would be heading further west.
This is useful to know when you are solving puzzle caches. For example if you are plotting numbers in Google Earth and see that the calculation takes you to the wrong location, do a whatif and see what happens if you increase either the latitude or longitude. Increasing/decreasing the latitude number by itself, will move your point due north/south. Alternatively, increasing/decreasing the longitude will move your point due east/west.
Degrees, minutes, seconds
Consider the co-ordinates shown on the Blackberry at the Dead Sea.
- N 310 38.664
- E 350 34.371
Since the world is circular (yes, I know it's almost a sphere, but work with me here!) it can be divided into 360 degrees. However because, as we discussed above, cartographers divided the earth in to north/south, latitudes only go from from 0 to 90 degrees in the North or South. Longitudes go from 0 to 180 East or West.
How far is one degree of Latitude?
You'll notice that latitudes are parallel lines wherever you are on earth. It means since the earth is almost a sphere, for geocaching purposes one degree of latitude is the same anywhere on earth. (OK the earth is slightly flat at the poles so latitude does vary but it's only a difference of about 1km between latitudes at the equator and the poles.)
A minute of latitude is 1/60th of a degree, and one second is 1/60th of a minute.
Geocaching uses Degrees, Minutes and Decimal minutes. You'll sometimes see it referred to as dd mm.mmm, for example in the setup menu of your GPS. Some puzzle caches will use Decimal Degrees to be tricky and these are expressed as dd.mmmm.
So how far is one degree, minute and second?
- 1° of Latitude (1/360th of the Earth's Polar circumference) is 110.5743 km (68.70768 miles)
- 1' (1 minute) of Latitude (1/60th of 1°) is 1.8429 km (1.1451 miles)
- 1" (1 second) of Latitude (1/3600th of 1°) is only 30.7151 m (100.771 feet)
- 0.1" (1/10th second) of Latitude (1/36000th of 1°) is only 3.07151 m (10.0771 feet)
So for co-ordinates in the Degree/Decimal Minute format (dd mm.mmm)...
- If the co-ordinates change by 1 degree you would have moved 110.6 kilometres
- If the co-ordinates change by 1 minute you would have moved 1844 metres
- If the co-ordinates change by 0.1 minutes you would have moved 184 metres
- If the co-ordinates change by .01 minutes you would have moved 18.4 metres
- If the co-ordinates change by .001 minutes you would have moved 1.84 metres.
So that third decimal place in the co-ordinates doesn't make a lot of difference - very useful information when you're trying to solve a puzzle cache. It's within the accuracy of your GPS. So you don't need to solve that number to get within a search radius. Even the second decimal place isn't that far away. It will get you somewhere pretty close. This is one of the secrets of finding puzzle caches.
In the puzzle you know the degrees are going to be the same as where you are (unless you're near a degree confluence). All you need to work out are the minutes and the first decimal point and you can see that you will be very close. Just plot some numbers on Google Earth until you find somewhere that looks likely.
How far is one degree of Longitude?
Because lines of longitude converge as you get closer to the poles, the distance between longitudes decreases as you move away from the equator and towards the poles. Therefore the distance depends on the latitude at which you are located.
For example at the equator, the distance between degree longitudes (say, between 150 and 151 degrees) is about 111.3 km. However at 35 degrees latitude that distance is only 91.2 km. Of course by the time you reach the pole it's zero.
Rather than digging out your old school scientific calculator, try this distance calculator here. It accepts various formats, so just use the usual geocaching dd mm.mmm.
Below is a table of distances between degree and minute longitudes that are calculated for latitudes from 0 to 90 degrees.
For example, if you are at 35 degrees latitude, then the distance between one degree longitudes is 91.2 km. The difference between one minute of longitude is 1.52 km. The distances are also shown in statute miles.
So you can now calculate distances for decimal minutes in the same way as for latitudes above i.e. At 35 degree latitude 0.1 minutes is 152 metres, 0.01 minutes is 15 metres and 0.001 minutes is 1.5 metres.[table "2" not found /]
Converting from Decimal Degrees to Decimal Minutes
Sometimes, people use Decimal Degrees in their cache puzzles i.e. dd.mmmm You need to convert these co-ordinates into Decimal Minutes which is what is used for most geocaches. Conversely you may want to convert from Decimal Minutes to Decimal Degrees.
It's actually very simple.
Since there are 60 minutes in a degree, to convert from Decimal Degrees to Minutes simply take the decimal part of the co-ordinate and multiply by 60. For example say the co-ordinate is S34.12345, multiply 60 x .12345 = 7.407. So your co-ordinate would be S34 07.407.
To convert from Decimal Minutes to Degrees divide the minutes by 60. So using our previous example, divide 7.407/60 = .12345.
It's the same process for either latitude or longitude co-ordinates.
Let me know if there is anything else that you would like to know about co-ordinates.
As you become more experienced in learning how to geocache you'll find that one of the rewards is the pleasure of finding the treasure at the end. After you expended considerable energy to find the thing it's something that makes it all worth it.
... unless it's a wretched micro! Man, I hate those things.
Not only are they hard to find but it is a pain to unroll a tiny scroll and find a space on it to jot your signature in microscopic letters. There is no joy at the end, only pain. A lot of people think the same. Check out what people DON'T like about some caches here.
Unless you're going to be very creative with a micro, just don't put them out. Unless you're going to be very creative with a micro, just don't put them out. Unless you're going to be very creative with a micro, just don't put them out. Unless you're going to be very creative with a micro, just don't put them out.
Did I just repeat myself?
Go for quality.
If you're a creative type who can design and construct unusual containers, then my choice of container is an ammo can. These things are relatively cheap, rugged and totally weatherproof. They last for years and you rarely have to maintain them. Stuff it full of quality goodies and find a fabulous location in which to hide it.
Sometimes an ammo can is too big and obvious for the location you have chosen. This is where you get to use your imagination. There are so many creative ways to hide things that will avoid using a nano or a micro. In fact you can purchase all sorts of camouflaged containers (e.g on eBay) that you don't need to think up something yourself.
By being unique and creative you will enhance your reputation in the geocaching community and people will look forward to doing your caches. You never know, they may come and ask you for advice on how to geocache.
Any dummy with a GPS can hide a geocache... many do; and have. The result has been a lot of "plastic trash" littering the countryside. Many people have left the game because it's hardly worth the effort. It's because so many people don't go to the effort of learning how to geocache properly.
Alternatively some people simply filter out the rubbish when they do searches. They may filter out micros (I often do!) or avoid caches hidden by certain geocachers.
Sometimes you spend a lot of time and effort solving a puzzle, or trekking a considerable distance or driving out of your way, only to find a micro, something with inaccurate co-ordinates, a location with no redeeming features, or some other feature that makes it hardly worth it.
If you're new to the game and want to learn how to geocache properly I'd suggest finding a variety of caches, say, at least 30 to 50 before even thinking about hiding one of your own. By variety, I mean traditionals, multi-caches, puzzle caches and containers of different sizes and shapes at different locations. You'll start to get an idea of what you like or don't like, and may gain some inspiration about what sort of cache you could hide.
A cache is like marketing your own product
Imagine you run a company that sells products. Your success depends on the quality of your products and the quality of your customer service.
Think of your caches in a similar way. You want to give people a great experience. You will get pleasure out of hearing about their experiences. In our survey most people said that they want to have great experiences and adventures. Give them that and they will love you for it.
Planning your cache
So you've done a few caches, and are getting an idea of what makes a good cache.
To help you along here is a checklist of what will make a good geocache:
- Great location - spectacular or scenic, historical interest, somewhere people wouldn't normally go to, etc...;
- Good size container e.g. ammo container (no micros!!!!!)
- Quality contents (not MacDonalds trinkets or the like) - something with some value
- Some challenge involved - physical and/or intellectual.
- Accurate co-ordinates
- Creativity in the hide (use your imagination!)
Is there a spot in your area that would be interesting to others.
Before you start, have a read of the guidelines on the main geocaching website.
If you want a cache that people enjoy visiting, DON'T consider these types of spots:
- Where there are no redeeming features - you just feel like putting something there because there is nothing there at the moment.
- The local mall - particularly Light Pole Caches (LPC);
- The local 7/11 or gas station;
- Near private property where your customers (err, other geocachers) would be uncomfortable visiting;
- Near the edge of cliffs or where you may endanger peoples' lives - unless you specifically intend that they use abseiling gear or the like.
Remember... GIVE PEOPLE A GOOD EXPERIENCE!
I don't know what it is, but there is something satisfying about finding a large container stuffed with quality contents. Conversely it's deflating to expend a lot of effort (e.g. a long hike) only to end up discovering.... a micro or it's evil cousin... the nano.
If you really must use a micro, it had better be something very creative!
Here are some examples of good containers:
- Ammo box
- Sealed drain pipe
- Container in a container
The container-in-a container is sometimes used where extra weatherproofing is needed. This is where a smaller container is placed inside a larger outer container. Both need to be weatherproof.
Over the years I have used and seen various types of containers in many different situations. By far the most reliable is the good ol' ammo container. These things are totally hermetic and are nice and roomy to comfortably hold a good assortment of contents.
Another big reason to use something like an ammo container is that they are a good investment. You will not need to continually replace the contents because they are waterlogged or replace the container because it is cracked or rodents have eaten holes in it.
I can also guarantee that people will give favourable comments because it is unusual.
And finally your reputation as a hider of quality cachers will be enhanced.
How to get accurate co-ordinates
There is nothing worse than wasting time trying to find a cache, only to discover that the co-ordinates are not accurate.
It's worth spending a bit of time making sure that the co-ordinates you publish are accurate. Again, people will give you favourable comments.
So once you've stashed your cache, mark the location on your GPS. I strongly suggest using a dedicated GPS (e.g. Garmin or Magellan). Don't use a Smartphone (e.g. iPhone, Android, Nokia, Blackberry) because the GPS is normally not as good as a proper GPS, and they usually don't have an averaging function.
Average the co-ordinates - usually found by pressing the menu button on your GPS. Leave it for several minutes until the distance to the cache minimizes. Save the co-ordinates.
Use the Find waypoint/geocache function using these co-ordinates. Walk 20 to 50 metres away from the cache and return to it. The distance should read less than 5 metres. If it doesn't, average the position again and repeat the procedure. In a difficult location, you may not get perfect co-ordinates but they will be close.
If you think the co-ordinates are going to be inaccurate, be sure to give a good hint.
So there are some tips on how to hide a quality geocache. Please feel free to add your own tips in the comment section below, or ask a question.