ASCE Surveying and Geomatics Flashcards

What is the purpose of astronomic azimuth determination in surveying?

Answer: To establish a true north reference for a survey without relying on magnetic north

Astronomic azimuth observations (on Polaris or the Sun) provide a true north reference independent of magnetic declination or assumed bearings.

What is the scale factor in State Plane Coordinate calculations?

Answer: A multiplier that converts ground distances to grid distances to account for map projection distortion

The scale factor converts ground (geodetic) distances to grid distances on the State Plane projection, accounting for the distortion inherent in projecting the curved Earth onto a flat plane.

In a topographic survey, what are contour lines?

Answer: Lines connecting points of equal elevation on a map

Contour lines are isolines on a topographic map that connect all points sharing the same elevation, conveying the shape and relief of terrain.

What is the purpose of a deed of dedication in surveying and land development?

Answer: To formally transfer private land to public use for streets, parks, or utilities

A deed of dedication transfers ownership of land shown on a plat (such as streets and public spaces) from the developer to the public or a government entity.

What is magnetic declination and how does it affect compass surveys?

Answer: The angular difference between true north and magnetic north; compass bearings must be corrected to get true bearings

Magnetic declination varies by location and changes over time; surveyors must apply this correction to convert magnetic compass readings to true bearings.

What is RTK GPS and what accuracy level does it typically achieve?

Answer: Real-Time Kinematic GPS; achieves centimeter-level accuracy by using carrier-phase measurements and a real-time base station correction

RTK GPS uses carrier-phase measurements and real-time corrections from a base station to achieve typical horizontal accuracies of 1–2 cm, suitable for control surveying.