Topic 14: State Plane Coordinates (SPCS)

Question 0

Common datums

Answer 0

NAD27 (North American Datum of 1927): the first major adjustment in control data was made in 1927. It used Clarke’s 1866 ellipsoid and had its origin at Meade’s Ranch in Kansas.
NAD83 replaced 1927 and has the center at the center of the earth. Has an accuracy of 1:200,000

Question 1

State plane coordinate system.

Answer 1

Provides a common datum of reference for horizontal control of all surveys over a large area. It uses simple Cartesian coordinate system rather than other complex spherical coordinates systems.

Question 2

Projection of SPCS

Answer 2

Points are project mathematically onto a flat plane.
Highly accurate within each zone.
Outside a specific state plane zone accuracy drops.

Question 3

There are two common methods for map projections.

Answer 3

1) Lambert Conformal Conic Projection

2) transverse Mercator projection. (Cylinder)

Question 4

Statistics

Answer 4

• each state contains one or more state plane zones, the boundaries of which usually follow county lines.
• there are 110 zones in the US.
  10 more in Alaska, 5 in Hawaii, and one in Puerto Rico and U.S. Virgin Islands.
  Total of 126 SPCS