Understanding Map Projections

POLAR STEREOGRAPHIC
Area
The farther from the pole, the greater the areal scale.
Direction
True direction from the pole. Local angles are true
everywhere.
Distance
The scale increases with distance from the center. If
a standard parallel is chosen rather than one of the
poles, this latitude represents the true scale, and the
scale nearer the pole is reduced.
The central meridian is 0°, and the latitude of origin is 90° S.
DESCRIPTION
The projection is equivalent to the polar aspect of
the Stereographic projection on a spheroid. The
central point is either the North Pole or the South
Pole. This is the only polar aspect planar projection
that is conformal. The Polar Stereographic projection
is used for all regions not included in the UTM
coordinate system, regions north of 84° N and south
of 80° S. Use UPS for these regions.
LIMITATIONS
Normally not extended more than 90 degrees from
the central pole because of increased scale and area
distortion.
USES AND APPLICATIONS
Polar regions (conformal).
In the UPS system, the scale factor at the pole is
0.994, which corresponds to a latitude of true scale
(standard parallel) at 81°06'52.3" N or S.
PROJECTION METHOD
Planar perspective projection, where one pole is
viewed from the other pole. Lines of latitude are
concentric circles. The distance between circles
increases with distance from the central pole.
POINT OF TANGENCY
A single point, either the North Pole or the South
Pole. If the plane is secant instead of tangent, the
point of global contact is a line of latitude.
LINEAR GRATICULES
All meridians.
PROPERTIES
Shape
Conformal; accurate representation of local shapes.
Supported map projections• 77