On Sun, 4 May 2008, Ray wrote:
> On May 4, 1:27 am, Brettster <brett.ba...@[EMAIL PROTECTED]
> wrote:
>> My regular walk to the Beverly Hills Public Library seems like a
>> gradual uphill climb -- nothing on par with San Francisco, but a very
>> slight incline most or all of the way. As you might expect, the walk
>> back home is a breeze. According to my handheld Garmin GPS, it's
>> exactly 1.75 miles each way. But I wondered exactly how much height I
>> was achieving on my walk, in addition to the distance. How can I tell?
>> Can a handheld device measure something like that? It could be several
>> feet or, I suppose, it could be more. I have utterly no idea. Any
>> ideas?
>
> All gps receivers calculate altitude (as the calculated position is a
> point in 3D space, not just a horizontal position), but whether they
> choose to display it is up to the unit. As previously mentioned,
> altitude is notoriously inaccurate - this is because the algorithm is
> biased to give preference to satellites that are near the horizon, in
> order to improve horizontal accuracy. Mine can be out by over 100 feet
> or more.
Data point: My car GPS (Mio) routinely re****ts my altitude to be some 25
to 30' higher than it actually is. Like two week ago when it re****ted my
altitude to be 35', when I was parked in a lot about 8' above MSL.
--
"Thank heavens I'm atheist, otherwise I'd be in fear of going
to hell." Veronique explains comparative religion.
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