PS PS Map Projections & Cartography

Question 1

What type of map projection preserves the shape of small areas but distorts area over large regions?

Accepted Answer

Conformal projection

Answer

Conformal projections preserve local angles and shapes, but they distort area as distance from the central meridian increases.

Question 2

The State Plane Coordinate System (SPCS) uses which two map projections depending on the orientation of the state?

Accepted Answer

Lambert Conformal Conic and Transverse Mercator

Answer

SPCS uses the Lambert Conformal Conic for east-west-oriented states and the Transverse Mercator for north-south-oriented states.

Question 3

What is the scale factor at the central meridian of a Transverse Mercator projection used in the State Plane Coordinate System?

Accepted Answer

Less than 1.0000

Answer

In SPCS Transverse Mercator zones, the scale factor at the central meridian is set slightly less than 1 (e.g., 0.9999) so that the projection surface secants the ellipsoid, reducing maximum distortion.

Question 4

Which datum and ellipsoid are used as the basis for the current North American State Plane Coordinate System (SPCS 83)?

Accepted Answer

NAD 83 / GRS 80 ellipsoid

Answer

SPCS 83 is referenced to NAD 83, which uses the GRS 80 ellipsoid as its geometric foundation.

Question 5

What is the purpose of a 'grid factor' (combined scale factor) in State Plane coordinate computations?

Accepted Answer

To convert ground distances to grid distances

Answer

The combined (grid) scale factor is multiplied by a ground distance to produce the corresponding grid distance on the State Plane projection.

(PS) Professional Licensed Surveyor Practice Test

(PS) Professional Licensed Surveyor Practice Test

PS PS Map Projections & Cartography