Arc 1960 to WGS84 Converter
About Arc 1960 Coordinate System
Arc 1960 is a historic geodetic datum used in East and Central Africa, covering countries including Kenya, Tanzania, Uganda, Burundi, and Rwanda. It uses the Clarke 1880 ellipsoid (a=6378249.145m, 1/f=293.465) and requires 7-parameter Helmert transformation for accurate conversion to WGS84. Arc 1960 was established as a refinement of the earlier Arc 1950 system.
Arc 1960 was established in 1960 as an updated adjustment of the Arc 1950 geodetic network, incorporating additional survey measurements and improved computation methods. It provided better accuracy for the growing mapping needs of East and Central African countries following independence.
Arc 1960 is still found in legacy mapping, historical cadastral surveys, and older infrastructure projects across East and Central Africa, particularly in Kenya, Tanzania, Uganda, Burundi, and Rwanda.
Arc 1960 served as a refined geodetic datum for East and Central Africa, improving upon Arc 1950 with additional survey observations for better accuracy.
Arc 1960 to WGS84 conversion requires a 7-parameter Helmert transformation. Parameters vary by country and region. Consult local surveying authorities for official values.
About WGS84 Coordinate System
WGS84 (World Geodetic System 1984) is the global standard geodetic reference system used by GPS. It defines an Earth-centered, Earth-fixed coordinate system and geodetic datum.
Developed by the U.S. Department of Defense in 1984, WGS84 has undergone several refinements (WGS84(G730), WGS84(G873), WGS84(G1150), WGS84(G1762)) to improve accuracy through GPS satellite observations.
WGS84 is the default coordinate system for GPS receivers worldwide. It is used in aviation, maritime navigation, Google Maps, OpenStreetMap, GIS applications, and scientific research.
WGS84 is the native coordinate system of the Global Positioning System (GPS), ensuring direct compatibility with all GPS receivers and satellite navigation systems worldwide.
As the most widely adopted geodetic datum, WGS84 provides a consistent global reference frame for mapping, surveying, and geospatial data exchange across international boundaries.
With continuous refinements, WGS84 achieves centimeter-level accuracy globally, making it suitable for high-precision applications like surveying, drone navigation, and scientific research.
Arc 1960 to WGS84 Conversion Guide
// Arc 1960 → WGS84 (7-parameter Helmert transformation)
// Between WGS84 ellipsoid and Clarke 1880 ellipsoid
// Step 1: Convert from Clarke 1880 to geocentric Cartesian
// Using source ellipsoid: a = 6378249.145, 1/f = 293.465
N = a_source / √(1 - e²_source × sin²(φ))
X = (N + h) × cos(φ) × cos(λ)
Y = (N + h) × cos(φ) × sin(λ)
Z = (N × (1 - e²_source) + h) × sin(φ)
// Step 2: Helmert 7-parameter transform (Arc 1960 → WGS84)
// Parameters: dx, dy, dz (m), rx, ry, rz (rad), s (ppm)
// Reverse sign for inverse transformation
X' = ΔX + (1 + s)(X + Rz·Y - Ry·Z)
Y' = ΔY + (1 + s)(-Rz·X + Y + Rx·Z)
Z' = ΔZ + (1 + s)(Ry·X - Rx·Y + Z)
// Step 3: Convert back to geodetic using WGS84 ellipsoid
// a = 6378137.0, 1/f = 298.257223563
p = √(X'² + Y'²)
θ = atan2(Z' × a_target, p × (1 - f_target))
φ' = atan2(Z' + e²_target × (1 - f_target) × a_target × sin³(θ),
p - e²_target × a_target × cos³(θ))
λ' = atan2(Y', X')Arc 1960 to WGS84 requires a full 7-parameter Helmert transformation because the two systems use different ellipsoids and different datum origins. The conversion accuracy depends on the quality of regional 7-parameter values used.
- Enter your Arc 1960 coordinates in the input field (latitude, longitude, one pair per line)
- Enter the appropriate 7-parameter Helmert values (dx, dy, dz, rx, ry, rz, s) for your region
- Click the Convert button to transform coordinates from Arc 1960 to WGS84
- Review the converted WGS84 coordinates in the output field
- Copy the results or save them as an XLSX file for further use
- Ensure coordinates are within valid ranges before conversion
- 7-parameter values are region-specific; obtain them from local surveying authorities
- Verify a sample of converted coordinates on your target platform
- All conversions are performed client-side for complete data privacy