by Joseph Hazelbaker

Created on: April 06, 2007   Last Updated: April 27, 2007

I love my GPS unit, but it doesn't work in all conditions and I can't use it during adventure races. As a result, I've been forced to maintain by map and compass navigation skills and not just rely on my GPS Unit. As compasses and maps have improved and adopted the coordinate system used by the GPS, I have found that the old technology can be just as good, and sometimes better, than the new.

A map and compass can equal or exceed a Global Position System (GPS) when the weather, topography, or your power source goes "south." Recently manufactured compasses and recently printed maps contain the same information and provide the same navigational capabilities that are offered by a GPS unit. The trick is to have the knowledge to get at that information, rather than just pushing a button on your GPS.

~ BACKGROUND ~

A GPS uses satellites in space to locate points on earth. The satellites are reference points and by using three such points or satellites, a position on earth can be "triangulated." Obviously, this requires that your GPS be able communicate via radio signal with at least three separate satellites at one time. It is a well-recognized fact that a map and compass provide greater overall utility because they can be used in conditions and places where GPS reception is poor or inaccessible. Such reception problems primarily relate to weather and interference.

~ SIGNAL INTERFERRENCE ~

Currently, the U.S. GPS Satellite Network consists of 24 satellites. This number allows for the theoretical ability to locate enough satellites to perform the needed triangulation from any location in the U.S. at any time. However, local weather conditions can impair reception. If even one of the available satellites has its radio signals impaired by weather (e.g. heavy clouds with or without precipitation), then the GPS unit could be rendered useless.

This problem also occurs when reception is impaired by human-made structures, such as bridges or buildings, or natural conditions such as mountains or heavy forest cover. If the GPS unit cannot receive a signal from more than two or three satellites, then the unit is useless.

~ OTHER GPS LIMITATIONS ~

In addition to the problems with signal interferrence, a map and compass don't require batteries and are much less fragile than a GPS unit. Drained or expired batteries and unit breakage are simply two more variables that can cause your unit to malfunction. These two variables don't exist with map and compass.

~ MAP & COMPASS DISADVANTAGES ~

The drawbacks to map and compass are that they require more refined navigational skills. However, by the time you read the owners manual, figure out what all the buttons and screens on your GPS unit mean, and convince yourself that you are getting accurate readouts you could have already mastered the basics map and compass navigation.

Moreover, current maps have the same coordinate system used by GPS. If you have a UTM grid, you can easily locate and plot points using the same coordinates you would use or find with your GPS. There is nothing you can do with a GPS unit that a map, compass, and UTM grid can't do equally.

~ CONCLUSION ~

In reality, it's wise to learn to use both a GPS and traditional navigation skills. If you spend a lot of time outdoors, both will come in hand at one time or another. Sometimes a GPS unit will be easier. Sometimes a map and compass will be your only choice. The problem is, it's hard to predict when one will be better than the other. All things being equal, choose both.

~ RESOURCES ~

Here are some resources for boning up on your navigations skills:

http://www.maptools.com/FreeTools/UTMtools.ht ml

http://www.worldar.com/nav/AR_Nav_Primer_v1.pdf

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