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THE FEUTEX TOOLKIT

Initial Great-Circle Bearing

Calculate the initial true bearing between two nonidentical geographic points.

Geospatial workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaInitial bearing clockwise from north = (atan2(sin((lon2-lon1)*PI/180)*cos(lat2*PI/180),cos(lat1*PI/180)*sin(lat2*PI/180)-sin(lat1*PI/180)*cos(lat2*PI/180)*cos((lon2-lon1)*PI/180))*180/PI+360)%360
Sources and model references

Worked example

Inputs

Start latitude
0 degrees
Start longitude
0 degrees
End latitude
0 degrees
End longitude
90 degrees

Expected results

Initial bearing clockwise from north
90 degrees

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Calculate the initial true bearing between two nonidentical geographic points.
  2. Set start latitude, start longitude, end latitude, end longitude in the indicated units.
  3. Calculate and compare initial bearing clockwise from north.

Try this example

{
  "lat1": 0,
  "lon1": 0,
  "lat2": 0,
  "lon2": 90
}

Accuracy and scope

Idealized educational model. Enter measured values in the displayed units; real systems may require additional corrections.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.