Surveying Measurements and Angle Correction

Flashcards covering surveying measurements, angle adjustments, and triangulation techniques.

Azimuth (Z)

Measured clockwise from true north (0°); Ranges from 0°– 360°.

Bearing

Always given as an acute angle (<90°); Uses compass directions: e.g., N30°E or S75°W.

Traverse Adjustment

Used to close polygon loops for location/path surveys.

Angle Correction Rule

Angle opposite longer side gets smaller; Angle opposite shorter side gets larger.

Length Correction Rule (Proportional)

Distribute corrections in proportion to segment lengths.

Compass Rule

Used to distribute coordinate (Δx, Δy) corrections proportionally.

Bowditch Rule

Same as Compass Rule; Assumes equal precision in angle and distance measurements.

Triangulation / Intersection

Used when you can measure angles but not distances. Uses ASA (Angle-Side-Angle): Two angles and the included side known.

Resection

Used to find unknown location from known points; SAS (Side-Angle-Side): Two sides and included angle known.

Mixture Case (SSA)

Two sides and an angle not between them; Can result in ambiguous cases (2 possible solutions).

Leveling

Process of determining height differences between points; Based on optical leveling and backsight/foresight measurements.

Interior angles

(n-2) x 180

Exterior angles:

(n+2) x 180

Deflection angles (full circle):

2π

Sum of given angles

interior angles traverse - the total of all interior angles of a polygon

correction per angle

misclosure / polygon sides

azimuth to bearing

the conversion from a clockwise angle measured from true north to a direction expressed in the format of degrees east or west of north.

law of sines

a/sin A = b/sin B = c/sin C

total linear misclosure

like taking the magnitude

relative precision

total distance / total misclosure

systematic error

a consistent error that occurs in measurements, often due to faulty equipment or an incorrect measuring process, leading to biased results.

random error

an unpredictable error that occurs due to various factors such as environmental changes or human variability, affecting the precision of measurements.