Class: Haversine

Inherits:
Object
  • Object
show all
Defined in:
lib/haversine.rb

Defined Under Namespace

Classes: Distance

Constant Summary collapse

RAD_PER_DEG =

PI/180

0.017453293

Class Method Summary collapse

Class Method Details

.calc(dlat, lat1, lat2, dlon) ⇒ Object 



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# File 'lib/haversine.rb', line 149

def self.calc dlat, lat1, lat2, dlon
  (Math.sin(dlat.rpd/2))**2 + Math.cos(lat1.rpd) * Math.cos((lat2.rpd)) * (Math.sin(dlon.rpd/2))**2    
end

.distance(lat1, lon1, lat2, lon2, units = :meters) ⇒ Object

given two lat/lon points, compute the distance between the two points using the haversine formula

the result will be a Hash of distances which are key'd by 'mi','km','ft', and 'm'



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# File 'lib/haversine.rb', line 139

def self.distance( lat1, lon1, lat2, lon2, units = :meters ) 
  dlon = lon2 - lon1
  dlat = lat2 - lat1

  a = calc(dlat, lat1, lat2, dlon)
  c = 2 * Math.atan2( Math.sqrt(a), Math.sqrt(1-a))

  Distance.new c
end

.units ⇒ Object 



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# File 'lib/haversine.rb', line 43

def units 
  [:miles, :km, :feet, :meters]
end

.wants?(unit_opts, unit) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/haversine.rb', line 153

def self.wants? unit_opts, unit
  unit_opts == unit || unit_opts[unit]    
end