Archive for January, 2006

Geocaching and GPS devices

Monday, January 23rd, 2006

Last Saturday we had a church outing, which included an afternoon walk through the woods. It wasn’t just your ordinary regular walk though; it was an actual geocaching trip.

One of the GPS devices we used for the geocaching trip

We were split in 10 groups, each with one of these GPS devices, and a piece of paper with the first set of coordinates written on them. Before we left, leaders of each group received an explanation on how to use the device, and then the groups were sent on their way, a couple of minutes apart.

Not everybody picked up the information that fast though, so when our group’s leader kept looking puzzled on receiving the information, I asked if I could help…

The instruction was short and simple: “this is where and how you enter the coordinates, and then you follow that arrow”. Well, up till we found the first location, this worked very well, and I thought it would be a breeze.

The purpose was to find a box on each location, in which there’d be a piece of paper with a multiple choice question. Each possible answer was linked to a set of GPS coordinates, so it was important to get the question answered correctly, in order to end up in the right spot for the next box.

The first question was easy too, and I entered the new coordinates into the GPS device. The route went North East, about 2 kilometers. We didn’t have a map, so we just had to find whichever path we thought would get us closest to the spot, and when we were only 200 meters from the second destination, we saw the box. Or so we thought.

When arriving at the box, the device still said North East, 140 meters. Obviously, that wasn’t our box. Soon another group arrived, and indeed, it was their box. So, I reckoned we should go another 140 meter North East, but that would be right across the river. As the river seemed to run from East to West, we started walking East, thinking we’d cross a bridge, walk back West, and find our box on the other side. As we walked, the arrow kept pointing North East, but the distance got greater with every step. Something seemed wrong, but I thought it was because the box was on the other side of the river.

Long story short: we walked 1 km to the first bridge, crossed it, walked 1 km in the opposite direction, only to find out that our box was indeed 140 meters from the other group’s box, but on the same river bank, in Western direction. Somehow, this GPS device didn’t do what it should have done: turn the arrow arround when we started walking in the wrong direction. I’m still not sure if that’s really what should have happened though, as there was another indication of direction on the device, that hadn’t been explained to me: the arrow was ‘broken’. The middle bit of it moves sideways when you’re off the right track. Had I known what this broken arrow meant, we would probably have found the second box much quicker 🙂

Anyway, looking at our box from the wrong side of the river, knowing it would be another 2km extra to get there and having tired children with us (mine) and a couple more tired people (not me), we decided to forget that second box and just go straight for the third (and final) one. We called the ‘cop out phone number’ and got the coords for the third box. GPS device said “South West, 2km”. Right across the river again. One of the brighter people among us decided to ask a passing cyclist whether the bridge in the Western direction would be closer than the one we just came from, and while it appeared to be the same distance, it would bring us closer to the third box than the other bridge, so we kept on walking West.

After we crossed that bridge, the device was pointing in the right direction, the road was straight, and all went fine. Until we got to 500 meters from the third box’ location: the lake. A big lake between us and the last box. The same lake also between us and the dinner that would be served after the walk. In the mean time it had gotten dark already, and some of us weren’t quite comfortable walking through the woods in the dark.

In the end we walked a couple hundred meters alongside the lake, until basically through miscommunication (too long a story to write down), we had to walk back to the road where we got picked up by a van, only to get back just in time for the leftovers from dinner — we were over an hour late!

Conclusion on geocaching: a fun thing to do, once you understand what the display on the GPS device really is saying 😉