Joel McNamara

Joel McNamara is a writer, technology consultant, and outdoor adventurer. He has worked in the computer industry for 25 years and advises international humanitarian organizations on safety and security issues. Joel is also the author of Geocaching For Dummies and Secrets of Computer Espionage.

Articles & Books From Joel McNamara

Article / Updated 03-26-2016
When the U.S. government turned off GPS Selective Availability (SA) in May 2000, it was like magic. Suddenly civilian GPS receivers that were formerly accurate to about 300 feet were accurate to 30 feet. This level of accuracy offered some creative possibilities. Three days after SA was turned off, a message appeared in the sci.
GPS For Dummies
GPS For Dummies gives new meaning to finding yourself. In fact, with a GPS (global positioning system) receiver, you can determine precisely where you are anywhere on this planet. If you’re are planning on buying a GPS receiver or if you have one and want to get your money’s worth, this guide tells you what you need to know, including: Basic GPS principles and concepts such as waypoints, routes, tracks, and coordinate systems Recommended features for GPS receivers to be used in various types of activities, including hiking, mountain biking, cross country skiing, geocaching, hunting, ATVing, mapping, and more How to do digital mapping on your computer, including software packages you can use to work with aerial photos, topographic maps, and road maps The main providers of digital map data for the U.
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