module GeoCalc::Bearing
Public Class Methods
bearing_to(base_point, point)
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Returns the (initial) bearing from this point to the supplied point, in degrees see(#williams.best.vwh.net/avform.htm#Crs)
@param [GeoPoint] Latitude/longitude of destination point
@return [Numeric] initial bearing in degrees from North
# File lib/geo_calc/calc/bearing.rb, line 15 def self.bearing_to base_point, point lat1 = base_point.lat.to_rad lat2 = point.lat.to_rad dlon = (point.lon - base_point.lon).to_rad y = Math.sin(dlon) * Math.cos(lat2) x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(dlon) bearing = Math.atan2(y, x) (bearing.to_deg + 360) % 360 end
final_bearing_to(base_point, point)
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Returns final bearing arriving at supplied destination point from this point; the final bearing will differ from the initial bearing by varying degrees according to distance and latitude
@param [GeoPoint] Latitude/longitude of destination point
@return [Numeric] final bearing in degrees from North
# File lib/geo_calc/calc/bearing.rb, line 38 def self.final_bearing_to base_point, point # get initial bearing from supplied point back to this point... lat1 = point.lat.to_rad lat2 = base_point.lat.to_rad dlon = (base_point.lon - point.lon).to_rad y = Math.sin(dlon) * Math.cos(lat2) x = Math.cos(lat1)*Math.sin(lat2) - Math.sin(lat1)*Math.cos(lat2)*Math.cos(dlon) bearing = Math.atan2(y, x) # ... & reverse it by adding 180° (bearing.to_deg+180) % 360 end
Public Instance Methods
bearing_to(point)
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@returns [Numeric] bearing in degrees
# File lib/geo_calc/calc/bearing.rb, line 4 def bearing_to point GeoCalc::Bearing.bearing_to self, point end
final_bearing_to(point)
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# File lib/geo_calc/calc/bearing.rb, line 27 def final_bearing_to point GeoCalc::Bearing.final_bearing_to self, point end