AccuLine 40-6910 Manual de instruções - Página 9

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AccuLine 40-6910 Manual de instruções
2595H
7/29/09
10:15 AM
Page 9
5.5 Determining difference in elevation
Measuring a difference in elevation from one set-up
To find the difference of elevation between two points which can be
observed from one position, set up and level your instrument about
midway between these points. Be sure that a leveling rod held on
both opposite points can be read when your telescope is level. Each
point should not be greater than 150 to 200 feet away from the
instrument or you may have difficulty reading the rods. The height of
the line of sight (horizontal crosshair) above or below each of the
points is found by reading the rod.
A line of sight 69 inches above A and 40 inches above B is shown
above. Therefore, B is higher than A by 29 inches.
Suppose one of your points is below the line of sight and the other
above (Fig. B), C is 4 feet 6-1/2 inches below the line of sight, and
point D, the underside of a floor beam is 7 feet 9-3/8 inches above
the line of sight (the latter reading having been obtained by holding
the rod upside down with the foot of the rod against the beam). D is
then higher than C by an amount equal to 4 feet 6-1/2 inches plus 7
feet 9-3/8 inches, or a total of 12 feet 3-7/8 inches.
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