I have an entry-level Garmin eTrex GPS device (no mapping involved) for walking. By default, it notes positions, waypoints, etc. in degrees of latitude and longitude. As long as one is connected to the ever more indispensible Internet, this is quite good fun. Routes and waypoints can be transferred between the GPS device and a clever piece of software such as Google Earth whereupon you can superimpose a visual representation of where you went, just in case you were unsure. Fun but not desperately useful. For walkers and cyclists meandering about the countryside without both laptop and expensive mobile phone Internet connection, current position noted in latitude and longitude coordinates is about as much use as a wheel clamp on a gondola.
A few days ago I discovered a setting enabling my eTrex to read out positions in British National Grid coordinates, as on an Ordnance Survey map. To be honest, I’d tried the setting some time ago but it didn’t seem to work. [Ed: user error!] This trip, I tried again with much more success. Lo and behold, current position and waypoints appeared in OS coordinates. Suddenly, rather than providing an historic log of a route for academic interest after the event, good ol’ eTrex became useful in real time. With this amendment, in answer to the age-old question, “where the flippin’ ‘eck are we?” (or words to that effect), I was now able to respond, “AB123986”. Actually, I could respond, “AB1234598765”, since Monsieur Garmin thinks he’s accurate to 10 digits (five on each axis). Try being that accurate on an OS Landranger 1¼inch/mile (2cms/1km) map! The point is, suddenly what had hitherto been a toy had become genuinely useful to walkers and cyclists alike.
Flushed with success and a series of new possibilities, I experimented further by manually entering a route of linked waypoints, such as where footpaths began, junctions to turn at, etc., into the eTrex using OS coordinates. Accuracy is the difficulty given the level of detail of maps. Boy Scouts, armed with a default OS 1¼inch/mile map, were taught to give 6-digit map references which are basically accurate to about 100m/300ft. Much better is an OS 2½in/mile map enabling a realistic estimate at 8-digit references; with this I was getting accurate to within about 30m/100ft. It is, of course, a complete pain in the digits entering “AB12349876” manually, one character at a time, from a scrolling list of characters for each and every position on your route. Planning a route beforehand is possible but arduous. However, If one is scratching one’s head wondering which junction on a map one has just arrived at, it answers the question admirably and is very useful.
Even our 2½in/mile map isn’t accurate enough on our campsite; there are far more tracks than the map actually shows so it’s still difficult to navigate a route with precision out of the site. Nonetheless, today we tried and popped off à bicyclette to have a look at Lymington. After a little while cycling down roads that seemed pretty obvious,we came to an unexpected junction. Up went the cry, “where the flippin’ ‘eck are we?” (or words to that effect), enquiringly. “Ah, hang on … we’re at AB123987” I was able to reply, helpfully. “How’d we get here? Turn left.”
Lymington is a well-shod, boaty-person sort of place. Anywhere requiring a “chandlery” (SZ327956) and refusing permission for a Weatherspoon’s is well-shod. In addition to granting permission for a chandlery, however, it had also granted permission for a very small local seafood establishment selling some excellent fresh crab sandwiches (SZ328955) which we sat on the harbour munching. A little way out of town at the start of our return trip, despite there being no Weatherspoon’s, we did come across the Chequers pub(SZ322936) selling some very good Ringwood brewery’s “Fortyniner” ale (4.9% ABV) which washed the crab sandwiches down admirably.
Thus much refreshed, we navigated our way back home to Guillaume (SU267001) on the road that we had originally intended to go on. OK, we did pause en route at a second hostelry in Sway (SZ283986) for a pint of Timothy Taylor’s Landlord (4.2% ABV). Well, we had cycled up a few inclines. 😉