(Caution, mostly geeky)
I first suspected I needed a Satnav in 2006. I got lost in outer Northampton and then lost again in Brackley. The Brackley incident was particularly annoying because my route planning was to follow signs to Brackley and then pick up signs to Oxford but there weren't any. Lots back to Northampton, the ring road and the Town Centre (which I visited several times) but nothing for Oxford. I just checked on Google Streetview and found some relevant signs but perhaps they weren't there in 2006, or it was dark and I was tired.
My next encounter with GPS technology was when a camera I bought came with a built in GPS. This was quite irritating because sorted itself out so slowly it tended to stamp the pictures with the position the camera had been in for the previous picture. Even when it didn’t do that, it was often wrong by 25m horizontally which annoyed me.
So finally I bought a Garmin Nuvi52LM. I first tried it out on foot because I'd had a few drinks. Whether that was the reason I decided to walk it the wrong way along one way street after telling it I was in a car I don't know. Perhaps I'm naturally cruel. Anyway, the little “you are here” symbol approached the one way section but refused to enter it. Suddenly it flipped and showed we were at the far end of the one way section. Patiently it waited until I got there. Walking back it was fine – that was legal. No way would it show me apparently breaking the law. Later I discovered how to turn on its voice. I must try this torment on it again and see if it says anything interesting or just whimpers. You're probably thinking by now I must have been one of those children who pulled the wings off of flies to see what happened but strangely enough, I wasn't..
Anyway, when I sobered up, I took it out and about in the car. I let it show me alternative routes to places I already knew. It did this rather well – choosing roads I didn't realise were the quickest route. It also showed up the optimism of my speedometer when it says 70mph it’s really 67! It's also fairly good at telling me what the current speed limit is which helps if I’ve been distracted as I passed a sign. Annoyingly, it “knew” there was a 50mph average speed check on part of the M5 when in fact there wasn't and I couldn't stop it going “dong”.
I downloaded some free software called Basecamp that lets you display your trips in minute detail. This revealed how clever the software is. The GPS system seems to detect (and log) quite a few “rubbish” positions – places over 100m from the road but doesn't usually worry you with them. To confuse it a little more, I took it on a walk alongside the River Severn well away from the road. It showed our position as 200m “out to sea” and at an elevation of -2m. In reality we were about 4m above the level of the water - and on dry land.
Another thing I found “off road” is that despite not being designed for the job, it's more useful than you might expect. Say you hope you're on a footpath that your (paper) map shows as joining a road at a distinctive junction. The device shows you as in the middle of nowhere but if when you walk, the indicator moves closer to the distinctive junction, that's good.
It also “believes” you'll do as you're told so if you turn off the motorway unexpectedly, it continues to log you on the “correct” route for 500 feet/10 seconds before flipping to your actual position on the slip road. After that bit of disobedience at junction 11A of the M5, it logged me nipping across country at 159 mph to explain the discrepancy. So if I'm ever accused of speeding, this gadget might not help as much as I'd like.
Not a bad early Christmas present to myself.