Module: RandomCoordinates

Defined in:
lib/random_coordinates.rb,
lib/random_coordinates/version.rb

Defined Under Namespace

Classes: Error

Constant Summary collapse

EARTH_RADIUS =

km

6371
VERSION = 
"0.1.0"

Class Method Summary collapse

Class Method Details

.at(centroid, radius, kml = nil) ⇒ random_lat, random_lng

Parameters:

  • centroid —

    The coordinates to start from (:lat, :lng)

  • The —

    maximum kilometers to go from central coordinates

  • kml (defaults to: nil) —

    The kml file to stay in, can be nil

Returns:

  • (random_lat, random_lng) 


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# File 'lib/random_coordinates.rb', line 14

def self.at(centroid, radius, kml=nil)
  max_distance = Math.sqrt(radius * 100 / 3)
  min_distance = Math.sqrt(radius * 100 / 8)

  # Latitude north/south
  distance = Random.rand(min_distance..max_distance)
  new_lat = distance * 180 / (Math::PI * EARTH_RADIUS)
  new_lat = Random.rand(0..1).zero? ? new_lat : -new_lat # north (+) or south (-)

  # Longitude east/west
  distance = Random.rand(min_distance..max_distance)
  new_lng = distance * 180 / (Math::PI * EARTH_RADIUS * Math.cos(new_lat * Math::PI / 180))
  new_lng = Random.rand(0..1).zero? ? new_lng : -new_lng # east (+) or west (-)

  random_lat = (centroid[:lat] + new_lat).round(5) # meter precision
  random_lng = (centroid[:lng] + new_lng).round(5) # meter precision

  unless kml.nil?
    boundary = BorderPatrol.parse_kml(File.read(kml))
    if !boundary.contains_point?(random_lng, random_lat)
      at(centroid, kml, radius)
    end
  end

  [random_lat, random_lng]
end