CH1903+ to WGS84 Converter
About CH1903+ Coordinate System
CH1903+ (Swiss Geodetic Datum 1903+) is the official geodetic datum for Switzerland and Liechtenstein. It uses the Bessel 1841 ellipsoid with a 3-parameter shift (dx=674.4m, dy=15.1m, dz=405.3m) from WGS84. CH1903+ is an improved version of the original CH1903 datum, providing higher accuracy for surveying and mapping.
CH1903 was originally established in 1903 as the first unified Swiss coordinate system. CH1903+ was introduced later as a refined version with improved accuracy using the Bessel 1841 ellipsoid and modern geodetic measurements. It has been the foundation for Swiss national mapping and the LV95 coordinate system.
CH1903+ is widely used in Switzerland and Liechtenstein for official surveying, cadastral mapping, engineering projects, and GIS applications. The newer LV95 (EPSG:2056) projection is based on CH1903+ and is the current standard for Swiss national coordinates.
CH1903+ is the official geodetic datum for Switzerland, used for all federal surveying, mapping, and land information systems.
CH1903+ uses the Bessel 1841 ellipsoid (a=6377397.155m, 1/f=299.1528128), a classical ellipsoid widely adopted in Central Europe.
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.
CH1903+ to WGS84 Conversion Guide
// CH1903+ → WGS84 coordinate transformation
// Using WGS84 ellipsoid (a = 6378137m, 1/f = 298.257223563)
// Geodetic to Cartesian (if needed for intermediate step):
N = a / √(1 - e² × sin²(φ))
X = N × cos(φ) × cos(λ)
Y = N × cos(φ) × sin(λ)
Z = N × (1 - e²) × sin(φ)
// Apply datum-specific transformation
// The exact parameters depend on the specific coordinate system
// Convert back to geodetic coordinates:
λ' = atan2(Y, X)
p = √(X² + Y²)
φ' = atan2(Z, p × (1 - e²)) // iterativeThe conversion between CH1903+ and WGS84 uses standard geodetic transformation methods, converting between geographic and geocentric coordinates and applying the appropriate datum transformation.
- Enter your CH1903+ coordinates in the input field (latitude, longitude, one pair per line)
- Click the Convert button to transform coordinates from CH1903+ 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
- For batch conversions, enter one coordinate pair per line
- Verify a sample of converted coordinates on your target platform
- All conversions are performed client-side for complete data privacy