Editing Map projection (section)

===Conic===
[[File:Usgs map albers equal area conic.PNG|thumb|upright=2|Albers conic]]

The term "conic projection" is used to refer to any projection in which [[Meridian (geography)|meridians]] are mapped to equally spaced lines radiating out from the apex and [[circles of latitude]] (parallels) are mapped to circular arcs centered on the apex.<ref>{{cite web |last1=Furuti |first1=Carlos A. |title=Conic Projections |url=https://www.progonos.com/furuti/MapProj/Normal/ProjCon/projCon.html |website=Prógonos |archive-url=https://web.archive.org/web/20161212000553/progonos.com/furuti/MapProj/Normal/ProjCon/projCon.html |archive-date=12 December 2016 |date=11 April 2016 |url-status=usurped}}</ref>
<!-- (or, [[mutatis mutandis]], more generally, radial lines from a fixed point are mapped to equally spaced radial lines and concentric circles around it are mapped to circular arcs). -->

When making a conic map, the map maker arbitrarily picks two standard parallels.  Those standard parallels may be visualized as [[secant line]]s where the cone intersects the globe—or, if the map maker chooses the same parallel twice, as the tangent line where the cone is tangent to the globe.  The resulting conic map has low distortion in scale, shape, and area near those standard parallels.  Distances along the parallels to the north of both standard parallels or to the south of both standard parallels are stretched; distances along parallels between the standard parallels are compressed.  When a single standard parallel is used, distances along all other parallels are stretched.

Conic projections that are commonly used are:
* [[Equidistant conic projection|Equidistant conic]], which keeps parallels evenly spaced along the meridians to preserve a constant distance scale along each meridian, typically the same or similar scale as along the standard parallels.
* [[Albers conic projection|Albers conic]], which adjusts the north-south distance between non-standard parallels to compensate for the east-west stretching or compression, giving an equal-area map.
* [[Lambert conformal conic projection|Lambert conformal conic]], which adjusts the north-south distance between non-standard parallels to equal the east-west stretching, giving a conformal map.