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Why do I need a GPS?

What is a GPS?

A GPS (or more technically, a GPS receiver; sometimes a GPS unit) is a device about the size of a smartphone that receives signals from satellites to provide precise location and time. Receiving the satellite signals is free; it requires no subscription.

Why not use a phone?

Yes, many phones have GPS capability built in. But for serious back-country exploring, you might want to invest in a dedicated GPS receiver for these reasons instead of relying on your phone:

Five basic functions

There are at least five basic functions you might want to perform with your GPS. On any given expedition, you might use several of them together or maybe all of them.

1. Measuring distance

It's always good for interest or bragging rights to know how far you walked, or you might need to know how far Point A is from Point B so you can give directions to someone else. This is otherwise difficult to estimate because your walking speed may vary significantly with the terrain, e.g., on slopes. "Gee, it seemed like a lot farther than that!" Or you may have some sort of fitness routine with a walking distance goal and you need to measure your progress. Your GPS may also calculate elapsed time, how much time you spend standing still, your average overall speed, and your average speed while moving.

2. Going to a specified point

Some hiking guides (e.g., yukonhiking.ca, Hikes and Bikes book, and THEN projects on this site) give GPS coordinates for key locations. These may include the trailhead (not always obvious where to start), key intersections ("When you get to this point, make sure you take the left fork in the trail."), and points of interest ("This is the lost portal of the Anaconda Mine."). If you have a point programmed into your GPS (loaded in by computer or entered manually) and tell your GPS to navigate to it, your GPS will provide you the straight-line distance to the point and show you the direction. It will also show on the screen your position relative to the point you're heading to, even if you don't have any maps programmed into your GPS.

Geocaching is all about finding your way to a specific point. And on THEN, points of interest (POIs) are all about visiting a specific location... see Downloads for POIs that you can load directly into your GPS so you can find them.

3. Marking a point

You might want to record a specific point so you can find it again. The most common situation is marking the location of your car when you start a hike so you have some hope of finding it again at the end. Or when you're walking, you might find the ultimate berry patch or some interesting historical artifact.

4. Tracking your progress during a hike

Your GPS will show a little line drawing of your path on the screen and any points you have loaded. This in itself is useful for retracing your steps to find the trail in the buckbrush if you're hiking above the treeline. If you have maps loaded, then you'll see your progress across the map instead of on a mostly blank screen. That gives you an idea of where you are with respect to other landmarks that you haven't programmed in as points. "No, I don't think we're completely lost... look, if we go another 200 metres this way, we should come out on the road."

5. Analyzing your track after a hike

The GPS keeps a record of the track you followed. You can transfer that track to Google Earth and see where you actually went in the context of other geographical features that you didn't appreciate while you were on the ground. You can also transfer the track to the free Garmin BaseCamp software program to obtain other info.

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See also:

How do I learn to use my GPS?

TimmiT History Exploration Notebook