OT: Question re GPS and geotagging

Mark Roberts mark at robertstech.com
Mon Oct 12 21:44:56 EDT 2009


A few thoughts:

I've owned several handheld GPS units, all either Magellan or Garmin.
I've found all the Magellans to be much more user friendly. 

For the past couple of years I've been working on a book about hiking
and photographing on the extensive trail system around Grandfather
Mountain. I've been gathering GPS data for the trails and for the
places where I've shot particularly good landscape shots, visiting
every place for which I intend to give co-ordinates multiple times
with multiple different units, so I've gained a *lot* of experience in
gathering GPS data for photographs. Here's my take: I would never even
consider a camera with built-in GPS. Nor one of those add-on GPS units
that goes on the hot shoe (neat idea, though). I will *only* consider
a GPS unit that shows me the co-ordinates *and* the margin for error
*and* the number of satellites it's tracking. The amount of variance
you can get with GPS (especially if you're somewhere interesting like
a mountain) is astonishing. Don't believe the accuracy statements you
read in the advertising, real-world accuracy can be orders of
magnitude worse (that's in the fine print of the ads).

On the top of a mountain or on a wide open plain you get amazing
accuracy. Low on a mountain or under heavy tree cover or in a valley
or some combination of those... you get awful accuracy. In between?
You get in between accuracy, of course. You want a GPS that will
*tell* you where you are in that vast expanse called "in between".





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