Random Developments

I really like GPS; it’s one of the cooler “general use” technologies out there.

GPS is the closest thing we have to a worldwide information network. Granted, it doesn’t really give you that much information: it will tell you where you are and what time it is (assuming you know your time zone), but nothing else. And, ok, it doesn’t really work indoors and accuracy is not great in urban areas (because of shadows and reflections caused by buildings), but it’s still very cool. Think about it: I can be (almost) anywhere in the world and a small handheld device will be able to tell me, in just a few seconds, exactly where I am using only information from a constellation of satellites flying overhead, unseen and ignored by most people. Fifty years ago this would be the stuff of sci-fi.

The reason I’m mentioning this is that I recently bought a handheld GPS receiver, and I spent a few hours playing with it yesterday. The reason for that is that I’ve recently started engaging in bushwalking (or “hiking” for those outside Australia and NZ) with the Melbourne Bushwalkers. After my first somewhat “serious” walk, in the area of the Lorne waterfalls (about 13km downhill in the rain…), I tried to identify the path the group followed on a map and failed miserably. So, I thought “wouldn’t it be nice to be able to record the track so I could, later, trace it on a map?”. Well, a GPS receiver is a good way of doing that.

The model I bought is a Magellan eXplorist 400. It’s a discontinued model, but it is fairly decent and there’s a healthy market of new units on eBay for very good prices. It can track up to 12 satellites and will use ground-based (WAAS) and satellite-based (EGNOS) auxiliary signals to increase accuracy where available; none of those are available in Australia, alas. It has a grayscale LCD display with a reddish (amber?) backlight and can display fairly detailed background maps (it won’t give you address-based directions or convert addresses to positions without additional software), and it uses SD cards as additional memory to record tracks, routes, points of interest and maps. It’s also fully waterproof (full immersion of up to 1m for up to 30 minutes), which is great for rainy days… And it comes with a USB cable to upload and download data from/to a computer.

I haven’t yet used it “in the field”, so I can’t talk much about it’s performance there; I hope to remedy this soon enough. I can’t talk about battery durability either, for now. I did try to use it in central Melbourne yesterday, with sort of mixed results… it does well in areas that are somewhat open, but “canyon-like” streets (with tall buildings on both sides) are usually blind spots (I wonder how it does in real canyons…). I uploaded the track log to Google Earth, generated a KML file and made a public Google Map from it, which is here; the recorded path is in a barely-visible light blue, and it actually covers about half of the path I followed; I guess it lost the signal in the other areas. The receiver was inside my backpack, which may also not be the best possible position for it.

I will be using it in future walks (and in a trip to remote areas later this year, where I plan to use GPS data to geotag the pictures I’ll take — and to not get lost, also), and I’ll write about how it does later on.