SURVEYING CH 5 Flashcards
The most commonly used reference datum is
mean sea level rise
The vertical height of a point above or below a reference datum is
referred to as the
reduced level or the level of a point
are used practically in all aspects of construction:
to produce ground contours on a plan; to enable the optimum
design of road, railway or canal gradients; to facilitate ground
modeling for accurate volumetric calculations.
reduced levels of
use of reduced levels
to enable the optimum design of road, railway or canal gradients
to facilitate ground modeling for accurate volumetric calculations
is the most widely used method for obtaining the
elevations of ground points relative to a reference datum and is
usually carried out as a separate procedure from that used for
fixing planimetric position
leveling
involves the measurement of vertical distance relative to
a horizontal line of sight
leveling
is one which at all points is normal to
the direction of the force of gravity as defined by a freely
suspended plumb-bob.
level line or level surface
is one that is normal to the direction
of the force of gravity at a particular point.
horizontal line or surface
is any reference surface to which the elevations of
points are referred
datum
most common datum
msl
In order to make MSL accessible to all users throughout the
country, a series of permanent marks were established, called
bench marks
is its height above or below a reference datum.
reduced level of a point
leveling methods
- Direct or spirit leveling
- Profile leveling
- Reciprocal Leveling
- Trigonometric Leveling
- Stadia leveling
- barometric leveling
- cross-section leveling
- borrow-pit leveling
types of direct or spirit leveling
- Differential Leveling
2.Double-rodded Leveling
3.Three-wire Leveling
is the process of determining difference in
elevation of points, some distance apart by a series of set ups of a
leveling instrument along a selected route.
direct or spirit leveling