# Calculating distance from lat/long **URL:** \ **Category:** Factual Questions\ **Created:** [September 14, 2007, 4:47pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193 "2007-09-14T16:47:32Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [September 14, 2007, 4:47pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/1 "2007-09-14T16:47:32Z")
I am making a signpost thingie for my yard that will have directional arrows pointing toward places I like, along with the distance in miles/kilometers. For example, there will be a Hilton Head, SC arrow and a Sint Maarten arrow. I will use a compass to approximate the direction each sign points, but how do I determine distance? I have entered the locations into GoogleEarth, so I have the longitude/latitude for each point, as well as the lat/long for my house. How do I go from that to distance? Thanks. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 14, 2007, 4:53pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/2 "2007-09-14T16:53:38Z")
[QUOTE=vetbridge] I am making a signpost thingie for my yard that will have directional arrows pointing toward places I like, along with the distance in miles/kilometers. For example, there will be a Hilton Head, SC arrow and a Sint Maarten arrow. I will use a compass to approximate the direction each sign points, but how do I determine distance? I have entered the locations into GoogleEarth, so I have the longitude/latitude for each point, as well as the lat/long for my house. How do I go from that to distance? Thanks. [/QUOTE] Here ya’ go: [http://jan.ucc.nau.edu/~cvm/latlongdist.html](http://jan.ucc.nau.edu/~cvm/latlongdist.html) ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [September 14, 2007, 5:00pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/3 "2007-09-14T17:00:36Z")
Thanks! Easier than I could have dreamed. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [September 14, 2007, 6:04pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/4 "2007-09-14T18:04:41Z")
Another source of data. [How Far Is It?](http://www.indo.com/distance/index.html) ---
**Author:** ![butler1850](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@butler1850](https://boards.straightdope.com/u/butler1850)\ **Post date:** [September 14, 2007, 6:23pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/5 "2007-09-14T18:23:33Z")
[QUOTE=vetbridge] I am making a signpost thingie for my yard that will have directional arrows pointing toward places I like, along with the distance in miles/kilometers. For example, there will be a Hilton Head, SC arrow and a Sint Maarten arrow. I will use a compass to approximate the direction each sign points, but how do I determine distance? I have entered the locations into GoogleEarth, so I have the longitude/latitude for each point, as well as the lat/long for my house. How do I go from that to distance? Thanks. [/QUOTE] Use the measuring tool… it’ll get you “close enough” to the center of a city, and when you zoom in on the path, you’ll get a good indication of the “great circle route departure bearing.” The measuring tool defaults to showing a great circle when you measure long distance across the globe. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [September 14, 2007, 6:23pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/6 "2007-09-14T18:23:37Z")
The next time you are in need of these type of calculations but have lost the above links, search for “[Great Circle Calculation](http://en.wikipedia.org/wiki/Great-circle_distance)”. ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [September 14, 2007, 6:39pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/7 "2007-09-14T18:39:09Z")
😃 > [@](#): > > spherical coordinates used by mathematicians and physicists, usually when considering other spheres than the Earth’s surface, the great-circle distance is found as follows. If \varphi;! is the azimuthal angle and heta;! the colatitude, then the spherical distance is given by > > \begin{align}{\color{white}\frac{\Big|}{|}}r,\Delta\widehat{\sigma} &=2r\arcsin\left(\sqrt{\sin^2\left(\frac{ heta\_f- heta\_s}{2}\right)+\sin( heta\_s)\sin( heta\_f)\sin^2\left(\frac{\Delta\varphi}{2}\right)}\right),\ &=r\arctan\left(\frac{\sqrt{\left(\sin heta\_f\sin\Delta\varphi\right)^2+\left(\sin heta\_s\cos heta\_f-\cos heta\_s\sin heta\_f\cos\Delta\varphi\right)^2}}{\cos heta\_s\cos heta\_f+\sin heta\_s\sin heta\_f\cos\Delta\varphi}\right);\end{align};! I like pie, not pi! ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [September 14, 2007, 7:11pm UTC](https://boards.straightdope.com/t/calculating-distance-from-lat-long/419193/8 "2007-09-14T19:11:27Z")
Google Earth has a Ruler tool on the toolbar that will tell you the distance.