Editing Map projection (section)

===Notable lines===<!-- [[Central meridian (map projections)]] links to this section -->
{{comparison_of_cartography_surface_development.svg|300px}}
The developable surface may also be either ''[[tangent]]'' or ''[[secant line|secant]]'' to the sphere or ellipsoid. Tangent means the surface touches but does not slice through the globe; secant means the surface does slice through the globe. Moving the developable surface away from contact with the globe never preserves or optimizes metric properties, so that possibility is not discussed further here.

Tangent and secant lines (''standard lines'') are represented undistorted. If these lines are a parallel of latitude, as in conical projections, it is called a ''standard parallel''. The ''central meridian'' is the meridian to which the globe is rotated before projecting. The central meridian (usually written ''λ''{{sub|0}}) and a parallel of origin (usually written ''φ''{{sub|0}}) are often used to define the origin of the map projection.<ref>{{cite web
  | url       = http://www.geography.hunter.cuny.edu/~jochen/GTECH361/lectures/lecture04/concepts/Map%20coordinate%20systems/Projection%20parameters.htm
  | title     = Projection parameters
  | last      = Albrecht
  | first     = Jochen
  | publisher = City University of New York
  }}</ref><ref>{{cite web
  | url          = http://edndoc.esri.com/arcsde/9.2/concepts/geometry/coordref/coordsys/projected/mapprojections.htm
  | archive-url  = https://web.archive.org/web/20181128234249/edndoc.esri.com/arcsde/9.2/concepts/geometry/coordref/coordsys/projected/mapprojections.htm
  | archive-date = 28 November 2018
  | title        = Map projections
  | website      = ArcSDE Developer Help
  }}</ref>