Geodetic Calculations - Redfearn's Formulae, Geographic to Grid

Given Latitude and Longitude, calculate Easting, Northing, Zone for a Universal Transverse Mercator (UTM) projection, Grid convergence and Point Scale Factor.

• The calculations are performed using the GRS80 ellipsoid which is used for Australia's new coordinate system (the Geocentric Datum of Australia - GDA) and is also compatible with the global coordinate system (WGS84) (a = 6,378,137.0 metres; 1/f = 298.25722210)
• Redfearn's formulae are used (Redfearn, Empire Survey Review, No. 69, 1948) to convert between latitude & longitude and easting, northing & zone for a UTM projection, such as the Map Grid of Australia (MGA) used in conjunction with the GDA. These formulae are accurate to better than 1mm in any zone.
• Latitude must be between 0° and +84°/-80°. South Latitude is negative (eg -35° 55' 56.12'').
• Longitude must be between 0° and ± 180°. West Longitude is negative (eg -148° 56' 25.12'').

• NOTE: Given Easting, Northing and Zone for a UTM projection, calculate Latitude, Longitude, Grid convergence and Point Factor use the Grid to Geographic version of Redfearn's Formula.

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