Course Description
This third course on the series on State Plane Coordinate Systems characterizes the types of distortions that occur with the Transverse Mercator and Lambert Conformal systems. The concept of “scale great than true,” “…less than true,” and “true” is discussed. The concept of the mapping angle is presented and demonstrated qualitatively for both types of projection systems. Typical SPCS constants for a selected number of zones for Transverse Mercator types and Lambert Mercator are shown, using them to reinforce the concept of the Central Meridian. The concept of the geoid is briefly reviewed before proceeding through the computational processes for reducing a ground distance to its geodetic equivalent using the sea level factor and then, using the scale factor to is grid distance equivalent. The process of computing the mapping angles for both types of projections is then covered, concluding with a discussion of how to apply them.
Objectives
- How distortions occur with each of the projection types is covered.
- The concept of scale less than true and scale greater than true is reinforced.
- The concept of the mapping angle for each system is presented, as well as the process of calculating it.
- The computational process for computing geodetic distances from the ground distances, and then applying the scale factor to develop grid distances is then discussed.
