HaversineFast

This takes advantage of C being faster at calculating double floating point values then say ruby. A project necessitated the haversine calculation frequently which would be sub optimal in ruby. There were gems that I found that did this which were either old (2+ years,) or they ran on ruby which defeated the purpose, or did a lot more then just calculate the minimum distance between two points on an ellipsoid. Either way this was a nice exercise to remove external dependencies and optimize a continuous calculation.

Per wikipedia:

Add this line to your application's Gemfile:

gem 'haversine_fast'

And then execute:

$ bundle

Or install it yourself as:

$ gem install haversine_fast

For a given starting location of lat-1, lng-1 and an ending location of lat-2, lng-2, use:

HaversineFast.calc_distance(30.1959496, -81.5497181, 30.279191, -81.3895320)

Examples via the rails console:

rails console
[2] pry(main)> HaversineFast.calc_distance(30.1959496, -81.5497181, 30.279191, -81.3895320)
=> 17.8579022904856
[3] pry(main)>

Note: The above result is in kilometers. To perform a calculation for miles, you can use the following:

[3] pry(main)> ( 0.62137 * HaversineFast.calc_distance(30.1959496, -81.5497181, 30.279191, -81.3895320) ).floor
=> 11
[4] pry(main)>

1. Fork it ( https://github.com/[my-github-username]/haversine_fast/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request