Re: Calculating a Distance on the Surface of the Earth
- From: davem@xxxxxxxxx (Dave Martindale)
- Date: Thu, 31 Jan 2008 03:35:28 +0000 (UTC)
Bob Ball <bobball@xxxxxxxxxxxxxxxxxx> writes:
The line he dropped to the earth's surface was shown by angle and symbol
as a right angle to the original tangential line. Straight down to the
earth's surface to me would be a radial line, one from the end of the
200km line toward the center of the earth.
There's a third possibility too: the "vertical" dropped line is
perpendicular to the earth's surface (or to the surface of a pool of
liquid) at the point it reaches the surface. This is the usual
definition of a "vertical" line to a surveyor.
If the earth was spherical, or is assumed to be a sphere, then a
vertical line perpendicular to the surface also goes through the centre
of the earth. But with an ellipsoidal earth, a vertical line misses the
centre, and a radial line isn't perpendicular to the surface (except at
the poles and on the equator).
Dave
.
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- Calculating a Distance on the Surface of the Earth
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- Re: Calculating a Distance on the Surface of the Earth
- From: Bruce Stemplewski
- Re: Calculating a Distance on the Surface of the Earth
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