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Geometry: find point a specific distance between two points

This is similar to this question, but kind of the opposite.

I have two geographic points (latitude, longitude) A and B. Let's say they're 40 nautical miles apart. I'd like to calculate the coordinates of the point 10 nautical miles from point A, on the line between A and B. I'm sure this is very basic math, but it's been YEARS since I've had to do this kind of math (some other kinds I use daily), so I'm stuck. Any pointers would be greatly appreciated. My code for this project is in Python, but math isn't language-specific, so I'm not really concerned about that -- I just want to know the formula.

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RustyAtMath Avatar asked Aug 05 '10 04:08

RustyAtMath


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1 Answers

You have two position vectors with (latitude, longitude). From those you can calculate your bearing from point A to point B (if you don't already know it). With a bearing and a distance you can calculate your new latitude and longitude.

All the math you need to know is referenced here: http://www.movable-type.co.uk/scripts/latlong.html. I deal with this stuff so infrequently it's nice to have that link saved somewhere (read: printed).

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Anthony Avatar answered Sep 28 '22 18:09

Anthony