I have explored many of the popular GPS navigation devices over approximately the last 10 years. I have about 20 devices, from about 8 manufacturers. As a EE with a software and hardware background, I worked on some of the first computerized maps and computer-attached displays in the 1970's.
It has been wonderful to see the technology mature, with the map and POI databases, display capability, position-location, and route-calculation all grow to the point where one can have almost all the roads in North America (or USA, or Europe) in a small battery-operated, pocket-sized, hand-held unit, for as little as $100.
Where we are now:
1. The map data is generally improving, but some few expensive units do not contain the "full" available coverage (notably the Nav in the Prius). Generally, the manufacturer pays for use of the map data.
2. The GPS receivers have gone from "you need a clear view of the sky" to "you can use it indoors" or "it can lay on the seat of the car". The best GPS receivers in common use, like the SIRF III, have reliable reception (except for areas with strong reflections ... generally amoung tall buildings), fast start-up times, and virtually "instant" re-aquire times.
3. A 12 to 16 million POI (Points of Interest) database can cover most businesses in the USA, but many units only offer 1 to 2 (or occasionally 6) million POI. Some have older (presumably less expensive to license) POI databases, but things are generally improving.
4. The displays, now "higher" resolution with good color and brightness (except in direct sunlight), are often only limited by the software and the Processor speeds.
5. Routing is a non-trivial calculation. Significant variations from assumed speeds still hinder accurate time estimates. Handling of turns, lack of sufficiently detailed traffic and signal light information also hinder accurate estimates. Occasionally, bad or incomplete map data is significant locally.
---- CAUTION ----
Remember, all GPS info and routing should be considered only as ADVICE or SUGGESTIONS from a wandering gypsy who might have been there some years ago, and might have forgotten, been mistaken, or ... things might have changed. When it says "Turn Left", you should check to see if there is a suitable road there, AND that it is SAFE and legal to make the turn.
See SOC/GID-Meter and CAN-Do Info
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