module GeoCalc::Distance
Public Class Methods
distance_to(base_point, point, precision = 4)
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Returns the distance from this point to the supplied point, in km (using Haversine formula)
from: Haversine formula - R. W. Sinnott, “Virtues of the Haversine”,
Sky and Telescope, vol 68, no 2, 1984
@param [GeoPoint] Latitude/longitude of destination point @param [Numeric] number of significant digits to use for returned value
@return [Numeric] distance in km between this point and destination point
# File lib/geo_calc/calc/distance.rb, line 23 def self.distance_to base_point, point, precision = 4 # default 4 sig figs reflects typical 0.3% accuracy of spherical model precision ||= 4 lat1 = base_point.lat.to_rad lon1 = base_point.lon.to_rad lat2 = point.lat.to_rad lon2 = point.lon.to_rad dlat = lat2 - lat1 dlon = lon2 - lon1 a = Math.sin(dlat/2) * Math.sin(dlat/2) + Math.cos(lat1) * Math.cos(lat2) * Math.sin(dlon/2) * Math.sin(dlon/2) c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)) d = base_point.earth_radius_km * c d.round(precision) end
Public Instance Methods
distance_to(point, precision = 4)
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# File lib/geo_calc/calc/distance.rb, line 8 def distance_to point, precision = 4 GeoCalc::Distance.distance_to self, point, precision end