Geodetic::Coordinate::UPS¶

Universal Polar Stereographic¶

The Universal Polar Stereographic (UPS) coordinate system covers the polar regions of the Earth that fall outside the UTM grid: latitudes north of 84°N and south of 80°S. It uses a stereographic projection centered on each pole.

Constructor¶

point = Geodetic::Coordinate::UPS.new(
  easting:    0.0,
  northing:   0.0,
  hemisphere: 'N',
  zone:       'Y'
)

easting — Easting coordinate in meters
northing — Northing coordinate in meters
hemisphere — 'N' for the North Pole region, 'S' for the South Pole region
zone — UPS zone letter

Zones¶

UPS divides each polar region into two zones based on longitude:

Hemisphere	Zones	Longitude Range
North	Y, Z	Y: 180°W to 0°; Z: 0° to 180°E
South	A, B	A: 180°W to 0°; B: 0° to 180°E

False Origin¶

Both easting and northing use a false origin of 2,000,000 meters to ensure all coordinate values remain positive within the projection.

Methods¶

Method	Description
`grid_convergence`	Returns the angular difference between grid north and true north at the point
`point_scale_factor`	Returns the scale distortion factor at the point's location
`valid?`	Returns `true` if the coordinates represent a valid UPS position

Universal Distance Methods¶

The universal distance_to method computes the Vincenty great-circle distance (in meters) to any other coordinate type. The straight_line_distance_to method computes the Euclidean distance in ECEF space. Both accept single or multiple targets.

ups_a = Geodetic::Coordinate::UPS.new(easting: 2000000.0, northing: 2000000.0, hemisphere: 'N', zone: 'Z')
ups_b = Geodetic::Coordinate::UPS.new(easting: 2100000.0, northing: 2100000.0, hemisphere: 'N', zone: 'Z')
ups_a.distance_to(ups_b)                # => Distance (meters, great-circle)
ups_a.straight_line_distance_to(ups_b)  # => Distance (meters, Euclidean)