Common Mistakes, Differential and Profile Leveling (Part 3) Flashcards
(15 cards)
5 Common Mistakes in Leveling
- Misreading the rod
- Incorrect recording
- Erroneous computations
- Rod not fully extended
- Moving turning points
(MIMER)
a fixed point of reference whose elevation is either known or assumed.
Benchmark (BM)
a reading taken on a rod held on a point of known or assumed elevation.
Backsight (BS)
a reading taken on a rod held on a point whose elevation is to be determined.
Foresight (FS)
measured from the center of the instrument to the rod on which a backsight is taken.
Backsight distance
the horizontal distance from the center of the instrument to the rod on which a foresight is taken.
Foresight distance
an intervening point between two bench marks upon which point foresight and backsight rod readings are taken to enable a leveling operation to continue from a new instrument position.
Turning point (TP)
the elevation of the line of sight of an instrument above or below a selected reference datum.
Height of instrument or height of collimation (HI)
curved line which graphically portrays the intersection of a vertical plane with the surface of the earth.
Profile
numerical designation given in terms of horizontal distance any point along a profile line is away from the starting point.
Stationing
taken along the centerline of the proposed project to provide an accurate representation of the ground surface.
Intermediate foresights or ground readings
points which are established along the profile level route at uniformly measured distances.
Full stations
any other intermediate point established along a profile level route which is not designated as a full station.
Plus stations
a process of drawing the vertical scale for a profile much larger than the horizontal scale in order to accentuate the differences in elevation.
Vertical exaggeration
a special heavy grade graphing paper used for plotting profiles.
Profile paper
