distance.rb in gis-distance-1.2.0

- old
+ new

@@ -1,14 +1,16 @@
+# frozen_string_literal: true
+
 # The GIS module serves as a namespace only.
 module GIS
   # The Distance class encapsulates methods related to geographic distance.
   class Distance
     # Error raised if latitude or longitude values are invalid.
     class Error < StandardError; end
 
     # The version of the gis-distance library
-    VERSION = '1.1.0'.freeze
+    VERSION = '1.2.0'
 
     # Create a new GIS::Distance object using the two sets of coordinates
     # that are provided.
     #
     # If invalid coordinates are provided a GIS::Distance::Error is raised.
@@ -26,13 +28,11 @@
       @distance = nil
     end
 
     # Returns the radius of the Earth in kilometers. The default is 6367.45.
     #
-    def radius
-      @radius
-    end
+    attr_reader :radius
 
     # Sets the radius of the Earth in kilometers. This is variable because
     # the Earth is not perfectly spherical, and you may wish to adjust it.
     #
     # However, the possible range of values is limited from 6357.0 to 6378.0.
@@ -42,85 +42,85 @@
     # The default value is 6367.45.
     #
     # See http://en.wikipedia.org/wiki/Earth_radius for more information.
     #
     def radius=(kms)
-      if kms < 6357.0 || kms > 6378.0
-        raise Error, "Proposed radius '#{kms}' is out of range"
-      end
+      raise Error, "Proposed radius '#{kms}' is out of range" if kms < 6357.0 || kms > 6378.0
       @radius = kms
     end
 
     # Returns the formula used to calculate the distance. The default formula
     # is 'haversine'.
     #--
     # See http://en.wikipedia.org/wiki/Haversine_formula for details.
-    def formula
-      @formula
-    end
+    attr_reader :formula
 
     # Sets the formula to be used internally for calculating the distance.
     # The default is 'haversine'. Your other option is 'cosines' (i.e. the
     # Law of Cosines).
     #
     # If an unsupported formula is provided a GIS::Distance::Error is raised.
     #
     def formula=(formula)
       case formula.to_s.downcase
-      when 'haversine'
-        @formula = 'haversine'
-      when 'cosines'
-        @formula = 'cosines'
-      else
-        raise Error, "Formula '#{formula}' not supported"
+        when 'haversine'
+          @formula = 'haversine'
+        when 'cosines'
+          @formula = 'cosines'
+        when 'vincenty'
+          @formula = 'vincenty'
+        else
+          raise Error, "Formula '#{formula}' not supported"
       end
     end
 
     # Returns the distance (in kilometers) between the two coordinates
     # provided in the constructor.
     #
     def distance
       @distance =
-      case @formula.to_s.downcase
-      when 'haversine'
-        haversine_formula
-      when 'cosines'
-        law_of_cosines_formula
-      end
+        case @formula.to_s.downcase
+          when 'haversine'
+            haversine_formula
+          when 'cosines'
+            law_of_cosines_formula
+          when 'vincenty'
+            vincenty_formula
+        end
     end
 
     private
 
     # Validate the latitude and longitude values. Latitudes must be between
     # 90.0 and -90.0 while longitudes must be between 180.0 and -180.0.
     #
     def validate(lat1, lon1, lat2, lon2)
-      [lat1, lat2].each{ |lat|
+      [lat1, lat2].each do |lat|
         if lat > 90 || lat < -90
           msg = "Latitude '#{lat}' is invalid - must be between -90 and 90"
           raise Error, msg
         end
-      }
+      end
 
-      [lon1, lon2].each{ |lon|
+      [lon1, lon2].each do |lon|
         if lon > 180 || lon < -180
           msg = "Longitude '#{lon}' is invalid - must be between -180 and 180"
           raise Error, msg
         end
-      }
+      end
     end
 
     # See https://en.wikipedia.org/wiki/Law_of_cosines
     #
     def law_of_cosines_formula
       sin1 = Math.sin(@latitude1 * Math::PI / 180)
       sin2 = Math.sin(@latitude2 * Math::PI / 180)
       cos1 = Math.cos(@latitude1 * Math::PI / 180)
       cos2 = Math.cos(@latitude2 * Math::PI / 180)
-      cos3 = Math.cos(@longitude2 * Math::PI / 180 - @longitude1 * Math::PI / 180)
+      cos3 = Math.cos((@longitude2 * Math::PI / 180) - (@longitude1 * Math::PI / 180))
 
-      Math.acos(sin1 * sin2 + cos1 * cos2 * cos3) * radius
+      Math.acos((sin1 * sin2) + (cos1 * cos2 * cos3)) * radius
     end
 
     # See http://en.wikipedia.org/wiki/Haversine_formula
     #
     def haversine_formula
@@ -130,18 +130,24 @@
       lon2 = @longitude2 * Math::PI / 180
 
       dlat = lat2 - lat1
       dlon = lon2 - lon1
 
-      a = ((Math.sin(dlat/2))**2) + (Math.cos(lat1) * Math.cos(lat2) * (Math.sin(dlon/2)) ** 2)
-      c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a))
+      a = (Math.sin(dlat / 2)**2) + (Math.cos(lat1) * Math.cos(lat2) * (Math.sin(dlon / 2)**2))
+      c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a))
 
       radius * c
     end
 
+    # See https://en.wikipedia.org/wiki/Vincenty's_formulae
+    def vincenty_formula
+      require 'rvincenty'
+      RVincenty.distance([@latitude1, @longitude1], [@latitude2, @longitude2]) / 1000.0
+    end
+
     # Add a custom method to the base Float class if it isn't already defined.
     class ::Float
-      unless self.respond_to?(:mi)
+      unless respond_to?(:mi)
         # Convert miles to kilometers.
         def mi
           self * 0.621371192
         end
       end