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On Mon, 25 Jul 2011 21:22:40 -0600, Bruce J. Pennino
 wrote:

> Second question: I have a laser level, high quality Nikon construction
> level, and a surveyor's total station.  The total station has an
> internal scale that I can estimate a vertical angle to plus or minus
> about 2.5 seconds. Can I use these instruments to establish horizontal
> lines on  a wall?

Make it a wall (or feature of a building) far, far away.  In 100 yards,
roughly a city block, an error of one inch in vertical positioning of your
head and sextant would give an error of one minute of angle.  So a one
inch error in 2500 yards would be about your total station's accuracy
limit.  At that distance, you would also have to take the curvature of the
earth into consideration to determine a "level", equipotential, or free
water surface elevation equivalent to your eye height.

The sextant at sea, when using the horizon as a reference, does not really
use the level line, tangent to the earth's surface, as used in ordinary
plane surveying.  Depending on the total station, you may be able to punch
in distance and temperature, and account for curvature and refraction . .
. I don't know for sure, but I think that would be your largest source of
error.

--
Richard . . .

Using Opera since the"Dog" died

   

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