Description
This projection is one of the best for middle latitudes. It is similar to the Albers conic equal area projection except that Lambert conformal conic portrays shape more accurately than area. The State Plane Coordinate System uses this projection for all zones that have a greater east–west extent.
- Learn more about the Albers conic equal area projection
- Learn more about the State Plane Coordinate System
Projection method
Conic projection normally based on two standard parallels, making it a secant projection. The latitude spacing increases beyond the standard parallels. This is the only common conic projection that represents the poles as a single point. Can also be defined with a single standard parallel and a scale factor. If the scale factor is not equal to 1.0, effectively the projection becomes a secant projection.
Lines of contact
If using a two standard parallel case, the two standard parallels.
If using a single standard parallel case, and the scale factor is 1.0, the standard parallel.
If using a single standard parallel and the scale factor is less than 1.0, the cone cuts the spheroid along two parallels.
Linear graticules
All meridians.
Properties
Shape
All graticular intersections are 90°. Small shapes are maintained.
Area
Minimal distortion near the standard parallels. Areal scale is reduced between standard parallels and increased beyond them.
Direction
Local angles are accurate throughout because of conformality.
Distance
Correct scale along the standard parallels. The scale is reduced between the parallels and increased beyond them.
Limitations
Best for regions predominantly east–west in extent and located in the middle north or south latitudes. Total latitude range should not exceed 35°.
Uses and applications
SPCS for all zones that are more east–west in extent.
USGS 71/2—minute quad sheets to match the State Plane Coordinate System.
Used for many new USGS maps created after 1957. It replaced the Polyconic projection.
Learn more about the Polyconic projection
Continental United States: standard parallels, 33° and 45° N.
Entire United States: standard parallels, 37° and 65° N.
Parameters
Desktop
- False Easting
- False Northing
- Central Meridian
- Standard Parallel 1
- Standard Parallel 2
- Scale factor
- Latitude of origin
Workstation
- 1st Standard Parallel
- 2nd Standard Parallel
- Central Meridian
- Latitude of projection's origin
- False Easting (meters)
- False Northing (meters)