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The 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 continental 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 coordinate system to specify locations rather than a more complex spherical coordinate system (the geographic coordinate system of latitude and longitude). By thus ignoring the curvature of the Earth, "plane surveying" methods can be used, speeding up and simplifying calculations. Second, the system is highly accurate within each zone (error less than 1:10,000). Outside a specific state plane zone accuracy rapidly declines, thus the system is not useful for regional or national mapping.

Most state plane zones are based on either a Transverse Mercator projection or a Lambert conformal conic projection. The choice between the two map projections is based on the shape of the state and its zones. States that are long in the east-west direction are typically divided into zones that are also long east-west. These zones use the Lambert conformal conic projection, because it is good at maintaining accuracy along an east-west axis. Zones that are long in the north-south direction use the Transverse Mercator projection because it is better at maintaining accuracy along a north-south axis. The panhandle of Alaska, whose maximum dimension is on a diagonal, uses an Oblique Mercator projection, which minimizes the combined error in the X and Y directions.


All State Plane zones in California

Click here to go back to the list off all State Plane grids

County or City SPCS27 Code SPCS83 Code
Alameda 10403 403
Alpine 10402 402
Amador 10402 402
Butte 10402 402
Calaveras 10403 403
Colusa 10402 402
Contra Costa 10403 403
Del Norte 10401 401
El Dorado 10402 402
Fresno 10404 404
Glenn 10402 402
Humboldt 10401 401
Imperial 10406 406
Inyo 10404 404
Kern 10405 405
Kings 10404 404
Lake 10402 402
Lassen 10401 401
Los Angeles 10407 405
San Clemente Island 10406 406
Santa Catalina Island 10406 406
Madera 10403 403
Marin 10403 403
Mariposa 10403 403
Mendocino 10402 402
Merced 10403 403
Modoc 10401 401
Mono 10403 403
Monterey 10404 404
Napa 10402 402
Nevada 10402 402
Orange 10406 406
Placer 10402 402
Plumas 10401 401
Riverside 10406 406
Sacramento 10402 402
San Benito 10404 404
San Bernardino 10405 405
San Diego 10406 406
San Francisco 10403 403
San Joaquin 10403 403
San Luis Obispo 10405 405
San Mateo 10403 403
Santa Barbara 10405 405
San Miguel Island 10405 405
Santa Barbara Island 10406 406
Santa Cruz Island 10405 405
Santa Rosa Island 10405 405
Santa Clara 10403 403
Santa Cruz 10403 403
Shasta 10401 401
Sierra 10402 402
Siskiyou 10401 401
Solano 10402 402
Sonoma 10402 402
Stanislaus 10403 403
Sutter 10402 402
Tehama 10401 401
Trinity 10401 401
Tulare 10404 404
Tuolumne 10403 403
Ventura 10405 405
Anacapa Island 10405 405
San Nicholas Island 10406 406
Yolo 10402 402
Yuba 10402 402

Click here to go back to the list off all State Plane grids