descriptive geomatry in engineering school

1. CH 3
BEARING , SLOPE,
AND GRADE

2. Bearing And Slop of Lines GL2:2

3. Bearing , Slope, and Grade
a
H
b
5
5
a
H
b
N
N
Bearing: a term used to describe the direction of a line on
the earth’s surface
Bearing of a line is
the angular
relationship of the
top view of the line
with respect to due
north or south,
expressed in
degrees.
The position of a line in space is described by its
bearing and slope , or by its bearing and grade .

4. Bearing , Slope, and Grade
a
H
b
b to a
N
a
H
b
55
N
55
a to b
In this traditional system it is customary to make the specified
angle less than 90 Selecting north or south accordingly as the base
direction .

5. GL2:5

6. a
H
125
o
N
Azimuth Bearing
b
a
H
b
The Azimuth bearing of a line is the clock wise departure
in degrees of the top view of the line from a base
direction, usually north.

7. Azimuth Bearing
GL2:7
305
A toward B
B toward A

8. GL2:8

9. a
h
a
F
a
1
20
o
b
b
b
H
F
H
1
N
D1
Problem:
A 160-m segment AB
of a power line has a
bearing of N 60
o
and
a downward slope of
20
o
from the given
point A. Complete the
front and top views.

11. Solution :
1- the bearing direction is
established at H plane.
2- the TL and θH is shown in
auxiliary view “1” projected
from H plane .
3- the location of point “b” is
transferred by projection .

12. Grade
Grade: a way to describe the inclination of a line with respect to a
horizontal plane

13. Grade
Grade of frontal line .

14. Grade of oblique line .

16. Points on Lines
GL
2:1
6

17. GL
2:1
7

18. GL
2:1
8

19. GL
2:1
9