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Re: Coordinates from iPhone

Subject: Re: Coordinates from iPhone
From: "Peter Shute" pshute2
Date: Tue Jun 25, 2013 8:12 pm ((PDT))
jtudor2005 wrote:
> If you use any GPS that can give you 'distance travelled'
> (whether a cheap or highly accurate model) and stand in one
> spot for a while, you'll find that you have 'travelled' quite
> some distance. The GPS coordinates will 'wander' over time,
> so any assumption of precision to 2 decimal places is
> misplaced. And if you are using it to log recording data, are
> you logging where the recorder is or the actual sound? So I'm
> not sure why 2 point precision is necessary. If you take a
> reading today, and then return tomorrow, you'll get a
> slightly different reading. Also, are you aware that 1 second
> is only 30 metres? So 2 decimal places is 30cm (12 inches)
> and that will easily be negated by trying to return to the
> exact same spot at some other time.

So you don't think it's worth recording even to 0.1". i.e. 3m? I've watched=
 my previous phone continue tracking when I'm stationary, but I would have =
said it was mostly moving around within 5m of me. Even if it was 10m, I wou=
ld have thought recording to the nearest 1" (30m) would be throwing away so=
me usable precision.

I've also done a little geocaching, and the coordinates supplied often get =
me within metres of the caches.

Peter Shute

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