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.
- Snyder, John Parr (1985). Chapter 5a A low-error conformal projection for a 50-State map of the United States; Appendix 9 Derivation of formulas for a low-error conformal projection for the 50 States (Abstract + pdf (74Mb)). "Computer-assisted map projection research". Bulletin (United States Geological Survey) 1629: pp.79–92; 147–51. Retrieved 26 March 2013.
- Snyder, John Parr (1987). 26 Modified-Stereographic Conformal projections (Abstract + pdf (22Mb)). "Map Projections: A Working Manual". Professional Paper (United States Geological Survey) 1395: 203–212. Retrieved 26 March 2013.