An azimuthal projection that is conformal. A standard variation of the Stereographic projection in polar aspect that is used with Universal Transverse Mercator (UTM) projection systems to represent polar regions.
True only where the central latitude crosses the central meridian or, alternatively, along a circle concentric about the projection center (or a parallel on the polar aspect). Scale is constant along any circle having its center at the projection center, but scale increases moderately with distance from the center within a hemisphere.
Only the center or the circle of true scale (if not the center) is free from all distortion. Areas grow greater the farther from the center, albeit in a conformal manner.
Employed in the UTM system to show North and South polar regions. Used from the North Pole to latitude 84 degrees North and from the South Pole to latitude 80 degrees South. In Universal Polar Sterographic projections the scale is reduced to 0.994, resulting in a standard parallel of about 81 degrees 07 minutes North or South.
The Universal Polar Stereographic projection is used only from the North Pole to 84 degrees latitude North and from the South Pole to 80 degrees latitude South.
Apparently developed in polar aspect by Egyptians and Greeks by the 2nd Century BC. Hipparchus was apparently the first Greek to use it and is generally considered its inventor.