Brunton Pocket Transit, Инструкция по эксплуатации

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Example: Tan(60°)
≠
Tan(30°) + Tan(30°) Find Tan(60°) from a table, use a calculator, or
step back until angle of inclination is less than 45°.
5.2.b Height Measurements Using % Grade
1. Sight % Grade using level or sloping ground, same as in Figures 22A & B, p. 11 .
2. Apply height calculation, as show in figures 23A & 24B.
A United States Geological Survey (USGS) topographic map is a 2-dimensional drawing of 3-
dimensional terrain. Hills, valleys, ridges, cliffs and other terrain are represented through a
series of contour lines. Each line represents constant elevation in feet or meters above sea
level. Find the contour interval in the legend of the topo-map. With practice, you’ll begin to
recognize contours, labeling and identify passable routes.
6.1 Map Azimuth
1. On the topo-map, place a “point” at a starting position and an “X” at a destination.
Example: Tan( 26.5°) = .499 = 49.9% Grade
5.2 Inclination Using Prismatic Compass
The pocket transit can also measure angles of inclination
without a tripod.
1. Open small sight and large sight as far as possible.
2. Flip peep sight up on large sight, .
3. Position Cover to approximately 45°.
4. With large sight pointing toward you, position transit
at eye-level with cover open to the left. (Fig 21)
5. Sight object behind transit, aligning small sight,
window and peep sight with object.
6. In mirror, adjust vernier until bubble in long level is centered.
5. Read inclination or percent grade at vernier’s center line.
5.2.a Height Measurement Using Vertical Angles
1. Sight inclination, as described in section 5.2.
2. Apply height calculation as shown in Figure 22A or 22B.
Note: Do not calculate tangent of an angle by adding tangents of two smaller angles.
Figure 22A Figure 22B
Height Measurement on
Level Ground
Height Measurement on
Sloping Ground
Sloping Ground
Height = (TanA - TanB) x Distance
Example: A = 38
°
, B = 10
°
& Distance = 75 ft.
Height = (Tan(38
°
) - Tan (10
°
))} x 75’
Height = (.781 - .176) x 75
Height = (.605) x 75
Height = 45.38 ft. = 45’
Level Ground
Height = (TanA + TanB) x Distance
Example: A = 36
°
, B = 10
°
& Distance = 50 ft.
Height = (Tan(36
°
) + Tan (10
°
)) x 50’
Height = (.727 + .176) x 50
Height = (.903) x 50
Height = 45.15 ft. = 45’
Level Ground
Height = (A + B) x Distance
Example: A = 72.7%, B = 17.6% & Distance = 50 ft.
Height = (72.7% + 17.6%)} x 50’
Height = (.903) x 50’
Height = 45.15 ft. = 45’
Sloping Ground
Height = (A - B) x Distance
Example: A = 78.1%, B = 17.6% & Distance = 75 ft.
Height = (78.1% - 17.6%) x 75’
Height = (.605) x 75’
Height = 45.38 ft. = 45’
Figure 23A Figure 23B
6 -- Compass Use with a Topographic Map
12 11
Figure 21