Distance between 2 points ?

[Gilletarom]

Hello Dave, hello JesperWe, Hello Pavel, Hello all,

Who can tell me how OpenCPN 3.0.2 calculates the distance between two points. for example
- The starting point 30 South 150 West
- Arrival 45 South 100 West,

Mathematical answer and accepted line of code in question.

Thank you in advance.

Gilletarom.

[JesperWe]

Most of the time it is calculated using ordinary trigonometry in Spherical Mercator coordinates.

The code is in DistanceBearingMercator() in the src/georef.cpp file.

The calculations will not be accurate over very long distances like in your example.

You can use the Route tool in the betas to see the difference between the SM (rhumbline) distance and the true Great Circle distance.