Quote:
Originally Posted by leevtr
I dont understand the way these things are supposed to work. No maps for africa/middle east, yet you can program waypoints from a paper map. Someome enlighten me. I know garmin/mapsource do a ' worldmap ', and supposedly its basic, yet i was told certain areas are not available, so what is it.
Help!!!!!!!!
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Basically the GPS unit knows where it is around the globe using long and lat, or whichever 'local' scale/grid you might be using as an alternative.
The mapping data is essentially an overlay (or technically an underlay) that the GPS uses to relate the actual pin point position to something you can relate to on the ground - be it a road, city, contour line etc.
More advanced GPS units (and the type you use in cars for example) can then interact the GPS point with the map to guide/route you in a certain direction (ie typically along a road) other than a straight line.
The 'problem' comes when the mapping data in the GPS doesn't accurately coincide with what is actually on the ground. Don't worry, the GPS always knows where it is in relation to long and lat, it's just the display screen might suggest you are in a slightly different position to what is on the ground, as the map data maybe slightly skewed at that particular point.
Hope that makes sense?
xxx
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