State Plane Coordinate System State Plane Coordinate System The State Plane Coordinate System (SPS or SPCS) is a set of 124 geographic zones or coordinate systems designed for specific regions of the United States. Each state contains one or more state plane zones, the boundaries of which usually follow county lines. There are 110 zones in the contiguous US, with 10 more in Alaska, 5 in Hawaii, and one for Puerto Rico and US Virgin Islands. The system is widely used for geographic data by state and local governments. Its popularity is due to at least two factors. First, it uses a simple Cartesian
F-plane is also poor near the equator, where variations in "f" are on the same order of magnitude as "f". The beta plane approximation is an improvement on the "f"-plane approximation which takes leading-order variations in "f" into account. F-plane In geophysical fluid dynamics, the "f"-plane approximation is an approximation where the Coriolis parameter, denoted "f", is set to a constant value. This approximation is frequently used for the analysis of highly idealized tropical cyclones. Using a constant Coriolis parameter prevents the formation of beta gyres which are largely responsible for the North-westward direction of most tropical cyclones. Rossby waves also