module Geocoder::Sql

def full_bearing(latitude, longitude, lat_attr, lon_attr, options = {})


http://www.beginningspatial.com/calculating_bearing_one_point_another
Based on:

(:linear or :spherical).
and an options hash which must include a :bearing value
Fairly accurate bearing calculation. Takes a latitude, longitude,
# 
def full_bearing(latitude, longitude, lat_attr, lon_attr, options = {})
  case options[:bearing] || Geocoder.config.distances
  when :linear
    "CAST(" +
      "DEGREES(ATAN2( " +
        "RADIANS(#{lon_attr} - #{longitude.to_f}), " +
        "RADIANS(#{lat_attr} - #{latitude.to_f})" +
      ")) + 360 " +
    "AS decimal) % 360"
  when :spherical
    "CAST(" +
      "DEGREES(ATAN2( " +
        "SIN(RADIANS(#{lon_attr} - #{longitude.to_f})) * " +
        "COS(RADIANS(#{lat_attr})), (" +
          "COS(RADIANS(#{latitude.to_f})) * SIN(RADIANS(#{lat_attr}))" +
        ") - (" +
          "SIN(RADIANS(#{latitude.to_f})) * COS(RADIANS(#{lat_attr})) * " +
          "COS(RADIANS(#{lon_attr} - #{longitude.to_f}))" +
        ")" +
      ")) + 360 " +
    "AS decimal) % 360"
  end
end