GS-50 projection with lines of constant scale

GS50 is a

map projection In cartography, map projection is the term used to describe a broad set of transformations employed to represent the two-dimensional curved surface of a globe on a plane. In a map projection, coordinates, often expressed as latitude and longitud ...

that was developed by John Parr Snyder of the

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...

in 1982. The GS50 projection provides a conformal projection suitable only for maps of the 50 United States. Scale varies less than 2% throughout the area covered. Distortion is very low as well. It is not a standard projection in the sense that it uses complex polynomials (of the tenth order) rather than a trigonometric formulation, though it was developed from an

oblique stereographic projection The stereographic projection, also known as the planisphere projection or the azimuthal conformal projection, is a conformal map projection whose use dates back to antiquity. Like the orthographic projection and gnomonic projection, the stere ...

References

* * {{cite journal , last1 = Snyder , first1 = John Parr , year = 1987 , title = Map Projections: A Working Manual , url = https://pubs.er.usgs.gov/publication/pp1395 , format = PDF , publisher =

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

, accessdate = 26 March 2013 , pages = 203–212 , journal = Professional Paper , volume = 1395 Map projections Conformal projections