measuring 10 km with 1m accuracy

Op Wed, 17 Feb 2010 01:00:10 +0100 schreef Andy <jonesandy@comcast.net>:
> On Feb 15, 3:00 pm, Paul Keinanen <keina...@sci.fi> wrote:
>>
>> Take a look what happens to the elevation display, when you walk below
>> a bridge, that obscures at least some of the satellites.
>
> Walking under a bridge selectively

I wonder what it could be like to walk under a bridge unselectively...

> also blocks out satelites at higher
> angles above the horizon, which as stated earlier, increases the error
> in the elevation calculation.

Unless you compensate by using data collected from an accelerometer.


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Rich Webb wrote:

> Frank Buss wrote:
>
>> I guess it would be difficult to get 1 m accuracy with a 10 km measuring
>> tape (non-planar ground, tape stretching etc.).
>
> It also depends on what one considers distance to be. Is it the straight
> cord between the points? Or the great circle distance?

IIUC, the latter is also called orthodromic distance.

http://en.wikipedia.org/wiki/Great-circle_distance

> Or the measured ground distance?

Taking into account terrain features, you mean?