# kristianmandrup/geo-distance

Calculates the geo distance between two locations using longitude and latitude, using Haversine, Speherical or Vincenty formula
Ruby
 Failed to load latest commit information. lib Jun 23, 2011 spec Jun 23, 2011 .document Jan 13, 2011 .gitignore Jan 11, 2016 .rspec Jan 13, 2011 Gemfile Jan 11, 2016 LICENSE.txt Jan 13, 2011 README.textile Jun 22, 2011 Rakefile Jan 11, 2016 VERSION Jan 11, 2016 geo-distance.gemspec Jan 11, 2016

# GeoDistance – geo distance calculations

Calculates the Geo distance between two locations using longitude and latitude.
This is done using “pure” Math formulas without resorting to Active Record or SQL DB functionality

This gem is meant to be a replacement for those geo distance utils out there that use built in SQL DB functionality for their calculations!

The formulas curently supported are

• Haversine
• Spherical
• Vincenty
• Flat

## Install & Usage

```require 'geo-distance'

it "should work" do
lon1 = -104.88544
lat1 = 39.06546

lon2 = -104.80
lat2 = lat1

dist = GeoDistance.distance( lat1, lon1, lat2, lon2 ) # in radians

dist = GeoDistance::Haversine.geo_distance( lat1, lon1, lat2, lon2 ).to_meters

# Change to (lng, lat) mode
GeoPoint.coord_mode = :lng_lat

p1, p2 = [[lon1, lat1].geo_point, [lon2, lat2].geo_point]

dist = GeoDistance::Haversine.geo_distance( lon1, lat1, lon2, lat2)
dist = GeoDistance::Haversine.geo_distance( p1, p2).to_miles

puts "the distance from  #{lat1}, #{lon1} to #{lat2}, #{lon2} is: #{dist.meters} meters"

dist.feet
dist.meters
dist.kms
dist.miles
end
```

## Distance API

The call to distance returns an instance of GeoDistance

`dist = GeoDistance::Haversine.distance( lat1, lon1, lat2, lon2 )`

The #kms, #meters, #miles and #feet methods return an instance og GeoUnit

`dist.kms`

### Setting default algorithm

You can also set a default algorithm to use…
The following will use the Haversine algorithm:

```  GeoDistance.default_algorithm = :haversine
dist = GeoDistance.distance( lat1, lon1, lat2, lon2 )
```

GeoDistance is used in the geo_magic gem

## Contributing to geo-distance

• Check out the specs and add specs to spec any added features or changes!
• Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet
• Fork the project
• Start a feature/bugfix branch
• Commit and push until you are happy with your contribution
• Make sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
• Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.