Automatic zone handling
For latitude/longitude input, the standard UTM zone and hemisphere are calculated automatically. Manual zone selection rejects a point outside the selected zone instead of returning misleading values.
Geodion tools
True ↔ grid heading converter
Convert between true heading and projected-grid heading using meridian convergence at a single position or across a CSV/XLSX file.
Automatic UTM zoneNorth and south hemispheresCSV/XLSX batch processing
Heading and position
Choose the projected coordinate system and enter either geographic or grid coordinates. For latitude/longitude input, the UTM hemisphere is derived from the signed latitude.
Calculations remain on this device
Batch processing
Process a CSV or XLSX file locally
Required columns: latitude, longitude and heading. Optional id and comments columns are preserved.
True, not magnetic
True heading is referenced to the local geodetic meridian. Magnetic declination is not included.
Single-point convergence
The result uses meridian convergence at each position. It does not include arc-to-chord or t−T corrections for a survey line.
UTM definition
Normal UTM coverage is 80°S to 84°N. Selecting an ellipsoid changes projection geometry only and does not perform a datum transformation.
British National Grid
BNG calculations are fixed to OSGB36 on Airy 1830. Geographic input must already be OSGB36 latitude and longitude.
Input validation
A heading is required. Latitude/longitude mode does not expose a conflicting hemisphere selector, while UTM grid coordinates require both zone and hemisphere.
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