You might remember that for the longest time, I was in the weird position of writing a blog about maps and mapping technology without so much as owning a single GPS receiver. That state came to an end last December, when I got a Celestron SkyScout for Christmas, and picked up a Nikon GP-1 geotagger shortly after that. (I wrote about the SkyScout in my post about GPS for amateur astronomers, and reviewed the GP-1 back in March.) But while GPS is integral to each of these gadgets, neither would be recognized as “a GPS” in the colloquial sense — i.e., a personal navigation device (PND) with maps and directions.

I’ve resisted buying one of those for years, not just because, as someone who’s been reading highway, street and topo maps from a very young age — I used to read highway maps until I got sick, which in my case was about five minutes — I didn’t see the need. I was also reluctant to put myself in a position where I’d be arguing with the device, disagreeing with the directions it gave me. And all the stories I posted to this blog about people blindly following their PNDs off cliffs or into rivers did not exactly persuade me that I needed one.

Even so, a bit more than three weeks ago, I actually bought one. More specifically, I bought a Garmin nüvi 255W — a rather inexpensive device with a 4.3-inch screen, text-to-speech directions, and not much else in the way of bells and whistles. (GPS Tracklog reviewed the nüvi 255W last year — favourably.)

So why did I do that, after going so long without one? What changed?

First of all, I actually saw one of these things in action. In July, I went on a road trip with some friends, one of whom brought along her PND — an older model, a Garmin Quest. We didn’t use its driving directions on the way down, but I still found value in knowing where were and how fast we were going; on the way back, with my home address in the system, we did use driving directions, and there it was interesting to see how an estimated time of arrival and time until the next turn.

I thought that PNDs were essentially for people who didn’t know where they were going, and I have never allowed myself to be that way. I thought that the question they answered was “where are we going?” I discovered that there were other questions it could answer as well: “where am I right now?” and “are we there yet?” So even a snooty old map reader like me could see some value in one of these things.

It also occurred to me that if I want to have any credibility when talking about PNDs, I really ought to have one myself — otherwise, I’d run the risk of speaking from a position of ignorance. Not only that, I figured I could use it as a baseline to which I can compare other PNDs, in case I want to start reviewing the things. And most important of all: I can write it off.

I settled on the Garmin nüvi 255W for a number of reasons. For one thing, it was on sale, and cost me less than $200 Canadian. But I wanted an entry-level unit at the outset, on the assumption that I would end up with many GPS units, each dedicated to a specific task, so I shouldn’t spend a lot on any one gadget. Based on my experience with what happened to Google Maps in my area when Google switched to Tele Atlas, I wanted something with Navteq maps. I also wanted something with at least nominal Mac compatibility, which pointed to Garmin.

I realize that I’m coming to this game so late that I run the risk of coming across as a blithering idiot if I present as some New Revelation something that everyone else has already figured out and now takes for granted. (See, for example, Fake Steve Jobs’s evisceration of tech blogger Henry Blodget, who’d never been in an Apple Store before last month.) So I have to be mindful of that. Having said that, after a few weeks of using the nüvi 255W, I can offer a few pithy observations:

First of all, the nüvi 255W is basic. It provides less on-screen information than the Quest despite its larger screen. (It gives me distance to the next turn, for example, but not time.) And that larger screen isn’t much use if you aren’t using 3D mode; in the 2D mode I use, with my current direction at top rather than north, there’s too little ahead of me and too much to the left and right of me. On the other hand, it’s handy for getting a general sense of the local street architecture in unfamiliar neighbourhoods.

It has given me some interesting directions that I’ve disagreed with, but none that would strike me as bizarre or outright wrong. If I’d blindly followed them, I would have gotten where I was going. We’ll see if anything truly interesting turns up.

It doesn’t do much besides car navigation: it’s a dedicated device. You can get coordinates for your current location, but only in degrees and decimal minutes, which makes using it to enter coordinates in another device — say, a computerized telescope that expects coordinates in degrees, minutes and seconds — less than convenient.

Suffice to say that my impression that GPS devices are quite specialized has not been challenged. This is my third GPS, and I will soon be picking up a fourth: I’ve ordered an HEQ5 Pro telescope mount with a GPS receiver. And after that, I will probably get a handheld unit — but with what features, I have no idea yet.

Bottom line: I’m getting a lot of GPS devices.

• Buy Garmin nüvi 255W at Amazon.com