Module: GeoTools::Location::ClassMethods

Defined in:
lib/geo_tools/location.rb

Instance Method Summary collapse

Instance Method Details

#acts_as_location ⇒ Object 



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# File 'lib/geo_tools/location.rb', line 10

def acts_as_location
  include InstanceMethodsOnActivation

  validates_numericality_of_for :latitude_degrees,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :less_than_or_equal_to    => 90,
                                :message                  => 'Degrees are invalid',
                                :for                      => :latitude

  validates_numericality_of_for :latitude_minutes,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :less_than                => 60,
                                :message                  => 'Minutes are invalid',
                                :for                      => :latitude

  validates_numericality_of_for :latitude_decimal_minutes,
                                :only_integer              => true,
                                :greater_than_or_equal_to  => 0,
                                :message                   => 'Decimal minutes are invalid',
                                :for                       => :latitude

  validates_numericality_of_for :latitude_decimal_minutes_width,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :for                      => :latitude

  validates_inclusion_of_for    :latitude_hemisphere,
                                :in      => %w( N S ),
                                :message => 'Hemisphere is invalid',
                                :for     => :latitude

  validates_numericality_of_for :longitude_degrees,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :less_than_or_equal_to    => 180,
                                :message                  => 'Degrees are invalid',
                                :for                      => :longitude

  validates_numericality_of_for :longitude_minutes,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :less_than                => 60,
                                :message                  => 'Minutes are invalid',
                                :for                      => :longitude

  validates_numericality_of_for :longitude_decimal_minutes,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :message                  => 'Decimal minutes are invalid',
                                :for                      => :longitude

  validates_numericality_of_for :longitude_decimal_minutes_width,
                                :only_integer             => true,
                                :greater_than_or_equal_to => 0,
                                :for                      => :longitude

  validates_inclusion_of_for    :longitude_hemisphere,
                                :in      => %w( E W ),
                                :message => 'Hemisphere is invalid',
                                :for     => :longitude

  before_validation :set_empty_values

  # Returns all locations within the given bounding box, to an accuracy of 1 minute.
  #
  # This is useful for finding all locations within the area covered by a Google map.
  #
  # The parameters should be positive/negative floats.
  named_scope :within, lambda { |sw_lat, sw_lng, ne_lat, ne_lng|
    sw_lat_degs = sw_lat.to_i.abs
    sw_lat_mins = ((sw_lat - sw_lat.to_i) * 60.0).round.abs
    ne_lat_degs = ne_lat.to_i.abs
    ne_lat_mins = ((ne_lat - ne_lat.to_i) * 60.0).round.abs

    sw_lng_degs = sw_lng.to_i.abs
    sw_lng_mins = ((sw_lng - sw_lng.to_i) * 60.0).round.abs
    ne_lng_degs = ne_lng.to_i.abs
    ne_lng_mins = ((ne_lng - ne_lng.to_i) * 60.0).round.abs

    # Latitude conditions.
    if sw_lat > 0 && ne_lat > 0       # northern hemisphere
      condition_lat_h  = 'latitude_hemisphere = "N"'
      condition_lat_sw = ["(latitude_degrees > ?) OR (latitude_degrees = ? AND latitude_minutes >= ?)", sw_lat_degs, sw_lat_degs, sw_lat_mins]
      condition_lat_ne = ["(latitude_degrees < ?) OR (latitude_degrees = ? AND latitude_minutes <= ?)", ne_lat_degs, ne_lat_degs, ne_lat_mins]
      condition_lat    = merge_conditions condition_lat_h, condition_lat_sw, condition_lat_ne

    elsif sw_lat < 0 && ne_lat < 0    # southern hemisphere
      condition_lat_h  = 'latitude_hemisphere = "S"'
      condition_lat_sw = ["(latitude_degrees < ?) OR (latitude_degrees = ? AND latitude_minutes <= ?)", sw_lat_degs, sw_lat_degs, sw_lat_mins]
      condition_lat_ne = ["(latitude_degrees > ?) OR (latitude_degrees = ? AND latitude_minutes >= ?)", ne_lat_degs, ne_lat_degs, ne_lat_mins]
      condition_lat    = merge_conditions condition_lat_h, condition_lat_sw, condition_lat_ne

    elsif sw_lat <= 0 && ne_lat >= 0  # straddles equator
      condition_lat_h  = 'latitude_hemisphere = "S"'
      condition_lat_sw = ["(latitude_degrees < ?) OR (latitude_degrees = ? AND latitude_minutes <= ?)", sw_lat_degs, sw_lat_degs, sw_lat_mins]
      condition_lat_s  = merge_conditions condition_lat_h, condition_lat_sw

      condition_lat_h  = 'latitude_hemisphere = "N"'
      condition_lat_ne = ["(latitude_degrees < ?) OR (latitude_degrees = ? AND latitude_minutes <= ?)", ne_lat_degs, ne_lat_degs, ne_lat_mins]
      condition_lat_n  = merge_conditions condition_lat_h, condition_lat_ne

      condition_lat    = merge_or_conditions condition_lat_s, condition_lat_n
    end

    # Longitude conditions.
    if sw_lng > 0 && ne_lng > 0       # eastern hemisphere
      condition_lng_h  = 'longitude_hemisphere = "E"'
      condition_lng_sw = ["(longitude_degrees > ?) OR (longitude_degrees = ? AND longitude_minutes >= ?)", sw_lng_degs, sw_lng_degs, sw_lng_mins]
      condition_lng_ne = ["(longitude_degrees < ?) OR (longitude_degrees = ? AND longitude_minutes <= ?)", ne_lng_degs, ne_lng_degs, ne_lng_mins]
      condition_lng    = merge_conditions condition_lng_h, condition_lng_sw, condition_lng_ne

    elsif sw_lng < 0 && ne_lng < 0    # western hemisphere
      condition_lng_h  = 'longitude_hemisphere = "W"'
      condition_lng_sw = ["(longitude_degrees < ?) OR (longitude_degrees = ? AND longitude_minutes <= ?)", sw_lng_degs, sw_lng_degs, sw_lng_mins]
      condition_lng_ne = ["(longitude_degrees > ?) OR (longitude_degrees = ? AND longitude_minutes >= ?)", ne_lng_degs, ne_lng_degs, ne_lng_mins]
      condition_lng    = merge_conditions condition_lng_h, condition_lng_sw, condition_lng_ne

    elsif sw_lng <= 0 && ne_lng >= 0  # straddles prime meridian
      condition_lng_h  = 'longitude_hemisphere = "W"'
      condition_lng_sw = ["(longitude_degrees < ?) OR (longitude_degrees = ? AND longitude_minutes <= ?)", sw_lng_degs, sw_lng_degs, sw_lng_mins]
      condition_lng_w  = merge_conditions condition_lng_h, condition_lng_sw

      condition_lng_h  = 'longitude_hemisphere = "E"'
      condition_lng_ne = ["(longitude_degrees < ?) OR (longitude_degrees = ? AND longitude_minutes <= ?)", ne_lng_degs, ne_lng_degs, ne_lng_mins]
      condition_lng_e  = merge_conditions condition_lng_h, condition_lng_ne

      condition_lng    = merge_or_conditions condition_lng_w, condition_lng_e
    end

    # Combined latitude and longitude conditions.
    {:conditions => merge_conditions(condition_lat, condition_lng)}
  }

  private

  # Merges conditions so that the result is a valid +condition+.
  # Adapted from ActiveRecord::Base#merge_conditions.
  def merge_or_conditions(*conditions)
    segments = []

    conditions.each do |condition|
      unless condition.blank?
        sql = sanitize_sql(condition)
        segments << sql unless sql.blank?
      end
    end

    "(#{segments.join(') OR (')})" unless segments.empty?
  end

end

#merge_or_conditions(*conditions) ⇒ Object

Merges conditions so that the result is a valid condition. Adapted from ActiveRecord::Base#merge_conditions.



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# File 'lib/geo_tools/location.rb', line 149

def merge_or_conditions(*conditions)
  segments = []

  conditions.each do |condition|
    unless condition.blank?
      sql = sanitize_sql(condition)
      segments << sql unless sql.blank?
    end
  end

  "(#{segments.join(') OR (')})" unless segments.empty?
end