Great circle calculator
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Great circle calculator
See also - Great circles
What is the Great circle calculator?
The Great circle calculator is a program written in Mircosoft Excel, that, when given two locations in the world, will plot calculate the length of the great circle connecting them, and plot this great circle on a world map.
The Great circle calculator is a program written in Mircosoft Excel, that, when given two locations in the world, will plot calculate the length of the great circle connecting them, and plot this great circle on a world map.
| great_circle_calculator.xls |
(Version 1.00, 283 KB)
What does the Great circle calculator do?
You enter two locations, either by choosing from the list of preset locations* or by inputting your own using latitude and longitude coordinates. The Great circle calculator will then....
Below is a screenshot from the program...
What does the Great circle calculator do?
You enter two locations, either by choosing from the list of preset locations* or by inputting your own using latitude and longitude coordinates. The Great circle calculator will then....
- Calculate the length and path of the great circle connecting the two locations
- Plot the great circle on a world map
- Calculate the length of the line going through the Earth that connects the two locations
- Calculate how long it would take to cover the distance of the great circle and line through the Earth at a speed you choose
Below is a screenshot from the program...
How does the Great circle calculator work?
The program uses the basic law of sperical trigonometry, which, when given the latitude and longitude of two locations, can find the angle (and hence the distance) between them. For more on this, I'd suggest reading my page on great circles.
Where did you get the information to write the Great circle calculator?
I first came across the spherical trigonometry law in Jean Meeus' book Astronomical Algorithms, but the law is widely known, and is easily found online (for example, see mathworld).
*Preset locations currently only include national capitals, although I am working to expand the list.
The program uses the basic law of sperical trigonometry, which, when given the latitude and longitude of two locations, can find the angle (and hence the distance) between them. For more on this, I'd suggest reading my page on great circles.
Where did you get the information to write the Great circle calculator?
I first came across the spherical trigonometry law in Jean Meeus' book Astronomical Algorithms, but the law is widely known, and is easily found online (for example, see mathworld).
*Preset locations currently only include national capitals, although I am working to expand the list.
