Great circle calculator

A great circle is the intersection of a sphere with a plane going through its center. A great circle is also a section of a sphere that contains a diameter of the sphere. The shorter segment between two points on a great circle is the shortest path between the two points on the sphere, also known as an orthodrome or the great circle distance.
You may calculate the great circle distance between two points on the Earth from the geographical coordinates. This is possible under the assumption that the Earth is a perfect sphere with a radius of 6371.0 km.

In addition, the shortest distance between the coordinates on the WGS84-ellipsoid is calculated. For the surface of the sphere the courses of departure and arrival are also given (True Course, clockwise, N = 0°).

Usage: Type the geographic coordinates of both points into the corresponding fields. The input may be either in degrees/minutes/seconds or as decimal degrees. The values will be converted, accordingly. Next click on the "calculate" button and read the result in the desired unit. Use the "reset" button to reset your calculation.
When the input is done in decimal degrees coordinates of westerly longitude and southerly latitude have a negative sign.

Example: What is the shortest distance between Hamburg (53°33′N, 9°59′E) and New York (40°43′N, 74°01′W)? Type the coordinates into the corresponding fields. Note the westerly longitude of New York. With every mouseclick the decimal coordinates are calculated, e.g. "-74.017" for the geographical longitude of New York. Finally click on the "calculate" button and read the result (e.g. 6130 km).

Remarks:
- Please note the remarks about the representation of numbers..
- There is no warranty for the calculation. Cactus2000 is not responsible for damage of any kind caused by wrong results.
- Please send an email if you have suggestions or if you would like to see more conversions to be included.

© Bernd Krüger, 04.10.2004, 11.05.2014