Surveying Written Exam 1

surveying

those activities involved in the planning and execution of

measurements for the location, design, construction, maintenance, and

operation of civil and other engineered projects

systematic error

errors for which the magnitude and the algebraic sign can be determined; can be eliminated from measurements when determined

random error

errors associated with the skill and vigilance of the surveyor; magnitude is unknown; tend to cancel out with multiple measurements

DMS

degree minute second (1 degree = 60’ ; 1’ = 60”)

chain

66 feet, 100 links

acre

66 ft x 660 ft (1 chain x 10 chains = 10 square chains)

hectare

100 m x 100 m = 10000 m²

link

0.66 feet (100 = 1 chain)

principle tasks of surveying

determining distance (horizontal, vertical, slope), angles (horizontal, vertical), and position (coordinates, elevation)

systematic and random

types of errors

accuracy

the relationship between the measured value and the true value

mistakes

due to inattention of the surveyor; can and should be eliminated

precision

the degree of refinement with which measurements are made

odometer

measures distance

EDM

electronic distance measurement

GPS

global positioning system

invar

material used for making surveying equipment, specifically tapes and rods

direct read, add tape, cut tape

types of readouts

6.5(10^-6)L/C or 11.7(10^-6)L/F

thermal expansion/contraction conversion factors

elevation

vertical distance above or below a reference datum

NGVD

national geodetic vertical datum

geoid

the shape that the ocean’s surface would take under the influence of gravity and rotation above, which is then extended through the continents

mean sea level

NAVD 88

vertical

aligned with the direction of the pole of earth’s gravity

horizontal

a straight line that is perpendicular to vertical

level

a curved line that is parallel to the geoid

benchmark

a permanent point of known elevation

temporary benchmark

only needed for completion of a project

turning point (TP)

a temporary spot to move level; where the rod is

side shot (same as IS)

intermediate sight taken in between turning points

differential leveling

finding difference in elevation between two points

zenith

angle measured downward from “up“

nadir

angle measured upward from “down“

meridian

longitudinal lines

theodolite (also called transit)

electronically measures angles precisely

(n-2)(180)

sum of interior angles

(n+2)(180)

sum of exterior angles

laying off angles

deflecting from straight line a certain amount/angle