Class: GoogleStaticMapsHelper::Location

Inherits:
Object
  • Object
show all
Defined in:
lib/google_static_maps_helper/location.rb

Overview

Represents a location with lat and lng values.

This classed is used internally to back up Markers' location and Paths' points.

Defined Under Namespace

Classes: NoLatKey, NoLatMethod, NoLngKey, NoLngMethod

Constant Summary collapse

EARTH_RADIUS_KM =

:nodoc:

6371
LAT_LNG_PRECISION =

:nodoc:

6

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Location

:call-seq: new(location_object_or_options, *args)

Creates a new Location which is used by Marker and Path object to represent it's locations.

:args: Either a location which responds to lat or lng, or a Hash which has :lat and :lng keys.

Raises:

  • (ArgumentError) 


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# File 'lib/google_static_maps_helper/location.rb', line 28

def initialize(*args)
  raise ArgumentError, "Must have some arguments." if args.length == 0
  
  if args.first.is_a? Hash
    extract_location_from_hash!(args.first)
  else
    extract_location_from_object(args.shift)
  end
end

Instance Attribute Details

#lat ⇒ Object

Returns the value of attribute lat.



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# File 'lib/google_static_maps_helper/location.rb', line 18

def lat
  @lat
end

#lng ⇒ Object

Returns the value of attribute lng.



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# File 'lib/google_static_maps_helper/location.rb', line 18

def lng
  @lng
end

Instance Method Details

#distance_to(location) ⇒ Object

Calculates the distance in meters to given location

location

Another location which you want the distance to



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# File 'lib/google_static_maps_helper/location.rb', line 43

def distance_to(location)
  dLat = deg2rad(location.lat - lat)
  dLon = deg2rad((location.lng - lng).abs)

  dPhi = Math.log(Math.tan(deg2rad(location.lat) / 2 + Math::PI / 4) / Math.tan(deg2rad(lat) / 2 + Math::PI / 4));
  q = (dLat.abs > 1e-10) ? dLat/dPhi : Math.cos(deg2rad(lat));

  dLon = 2 * Math::PI - dLon if (dLon > Math::PI) 
  d = Math.sqrt(dLat * dLat + q * q * dLon * dLon); 

  (d * EARTH_RADIUS_KM * 1000).round
end

#endpoint(distance, heading) ⇒ Object

Returns a new Location which has given distance and heading from current location

distance

The distance in meters for the new Location from current

heading

The heading in degrees we should go from current



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# File 'lib/google_static_maps_helper/location.rb', line 62

def endpoint(distance, heading)
  d = (distance / 1000.0) / EARTH_RADIUS_KM;
  heading = deg2rad(heading);

  oX = lng * Math::PI / 180;
  oY = lat * Math::PI / 180;

  y = Math.asin(Math.sin(oY) * Math.cos(d) + Math.cos(oY) * Math.sin(d) * Math.cos(heading));
  x = oX + Math.atan2(Math.sin(heading) * Math.sin(d) * Math.cos(oY), Math.cos(d) - Math.sin(oY) * Math.sin(y));

  y = y * 180 / Math::PI;
  x = x * 180 / Math::PI;

  self.class.new(:lat => y, :lng => x)
end

#endpoints_for_circle_with_radius(radius, steps = 30) ⇒ Object

Returns ends poionts which will make up a circle around current location and have given radius

Raises:

  • (ArgumentError) 


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# File 'lib/google_static_maps_helper/location.rb', line 81

def endpoints_for_circle_with_radius(radius, steps = 30)
  raise ArgumentError, "Number of points has to be in range of 1..360!" unless (1..360).include? steps

  points = []
  steps.times do |i|
    points << endpoint(radius, i * 360 / steps)
  end
  points << points.first

  points 
end

#to_url ⇒ Object

Returning the location as a string "lat,lng"



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# File 'lib/google_static_maps_helper/location.rb', line 96

def to_url # :nodoc:
  [lat, lng].join(',')
end