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Tutorial: How to select a GPS unit
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What Is GPS?

A Global Positioning System (GPS) is a satellite navigation system that works by continually transmitting high-frequency radio signals containing the time and location of the satellite in relation to earth. A GPS receiver on the Earth's surface obtains this information from three or more satellites and the GPS receiver calculates the user's position on the planet. The receiver pinpoints (between 3 and 15 meters) where the device and thus the user is located. With multiple measurements, the receiver can also calculate speed, trip time, distance to destination, altitude, sunrise and sunset, and more.

On average, eight satellites are always within sight of wherever you are on Earth. The more satellites your GPS receiver can contact, the more accurate your readings will be.

 

There are a few important differences in GPS units that should be understood before deciding on a unit to purchase.  For hiking and backpacking. you will definitely want a handheld unit so we’ll concentrate on those.

Manufacturers typically produce two types of handhelds. These are Basic and Mapping units. Below are a few general features for each type of unit that should help you choose the appropriate one for your needs.

Basic Units:
  • Look for units with 12 parallel channel capability.(this means that they can track up to 12   satellites for better speed and accuracy especially under tree cover where reception can    be greatly limited)
  • Main function is to record waypoints and tracks.
  • Do not include pre-loaded maps and cannot have maps installed into them.
  • Generally do not include additional memory.
  • Trackback capability such as Garmin's TracBack(r) feature is worth looking for. This             feature will allow your GPS unit to guide you back to your starting point.
  • Most basic and mapping GPS units are either completely waterproof or at least            submersible for up to a specified number of minutes. This in sharp contrast to digital             cameras -sigh!
  • Basic units are a good value if you only wish to record Latitude, Longitude, and                     waypoints on the track.
  • Basic Garmin Etrex units include the Summit, the Camo, and the Basic models.

    • Mapping Units:
  • These models provide several more features over most basic gps.
  • Usually contain pre-loaded points of interest maps or a detailed basemap.
  • More detailed maps can be uploaded into the unit including topographic and highly detailed street maps.
  • Additional memory can range from 1 megabyte to 24 megabytes as in the Vista.
  • Garmin models come with a PC serial interface cable as part of the package (newer models connect via USB which is a big advantage for more speedy uploading of topo maps and track logs and for downloading tracks and waypoints).
  • Virtually all of these are 12 parallel channel and some now include WAAS (wide area augmentation system) accuracy. This is a combination of ground and satellite positioning that is still in development and there are currently few WAAS satellites and none over most of Canada.
  • Some of the higher end models also include barometric altimeters and electronic compasses (Vista).
  • Vehicle mounting brackets can be purchased for your handheld unit so it can also be used as an automotive unit.
  • Mapping Garmin units include the Venture, the Legend, and the Vista plus the newer GPSMap 60 and GPSMap 60CS (with compass).
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    60cslrg

    So, what do I use and how does it work?
  • All of the trail maps available on this website have been tracked by this unit (Garmin Vista). In addition to the features above, the unit itself has performed quite well, even in forested areas and is fairly simple to use. However dense forest and deep gulleys limit the “sight” the unit has for satellites and can result in temporary signal loss. I did find that it works best at shoulder height attached to the shoulder strap of my backpack and level with the ground.
  • The Garmin firmware is updated regularly and you can download the revisions and upload these to your unit. A fresh set of alkaline AA batteries (2) are usually good for two average length hikes at best making rechargeable nickel metal hydride batteries a better buy. Finally, always take extra batteries with you. The trackback feature is of little use if your batteries run out. I have had some trouble with the Vista and rechargeable NiMH batteries in which the unit would shut down for no reason. It seems that these rechargeable batteries are slightly smaller in diameter than regular batteries and this may result in some “looseness” in the battery compartment. Placing some light card stock under the batteries or winding a bit of hockey tape around the battery itself seems to help. Also periodically carefully stretch out the battery contact springs to keep the battery snug.
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    An Update:
  • I recently purchased a second GPS with more memory and the ability to upload Garmin Mapsource maps which are the maps you see on the newer PDF trail maps on this site. The added benefit of a colour display is obvious on first use with even small creeks shown on the maps. Still not all areas have such detailed maps. On hike M01 even Dendrich Creek is not shown yet much smaller creeks appear in other regions. So map coverage detail is not uniform. The new GPS is the Garmin GPSMap 60CS. It is very good but somewhat slow in acquiring satellites in new locations which can take up to 10 minutes. Of course you can reduce this time by “telling” the gps it is in a new location. This is helpful if you are over 100 km from where you last used the gps. Again, sharp jolts can shut the unit down -likely due to momentary loss of contact with the batteries
  • The downloadable track files on this site can be uploaded through EasyGPS to almost any GPS. Of course the map detail you see on this site will not be available unless you purchase Mapsource Canada from Garmin. Other manufacturers have similar map products for their units. I have not seen a comparison of the detail available on maps by different providers. Unfortunately there is no uniform map standards between different GPS manufacturers. You must by Company A maps for Company A GPS units. They have you!
  • While this account focuses on Garmin units as that is where my knowledge lies, other manufacturers such as Lowrance and Magellan also make quality GPS units.
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