Template:POTD/2016-07-08
The American Polyconic projection is a map projection conceptualized as "rolling" a cone tangent to the Earth at all parallels of latitude, rather than as a single cone as in a normal conic projection. Each parallel is a circular arc of true scale. The scale is also true on the central meridian of the projection. The projection was in common use by many map-making agencies of the United States from the time of its proposal by Ferdinand Rudolph Hassler in 1825 until the middle of the 20th century.Photograph: JJ Harrison