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module Mongoid
module Geospatial
# Point
#
class Point
include Enumerable
attr_accessor :x, :y, :z
def initialize(x, y, z = nil)
@x = x
@y = y
@z = z
end
# Object -> Database
# Let's store NilClass if we are invalid.
#
# @return (Array)
def mongoize
return nil unless x && y
[x, y]
end
alias to_a mongoize
alias to_xy mongoize
def [](args)
mongoize[args]
end
def each
yield x
yield y
end
#
# Point representation as a Hash
#
# @return [Hash] with { xl => x, yl => y }
#
def to_hsh(xl = :x, yl = :y)
{ xl => x, yl => y }
end
alias to_hash to_hsh
#
# Helper for [self, radius]
#
# @return [Array] with [self, radius]
#
def radius(r = 1)
[mongoize, r]
end
#
# Radius Sphere
#
# Validates that #x & #y are `Numeric`
#
# @return [Array] with [self, radius / earth radius]
#
def radius_sphere(r = 1, unit = :km)
radius r.to_f / Mongoid::Geospatial.earth_radius[unit]
end
#
# Am I valid?
#
# Validates that #x & #y are `Numeric`
#
# @return [Boolean] if self #x && #y are valid
#
def valid?
x && y && x.is_a?(Numeric) && y.is_a?(Numeric)
end
#
# Point definition as string
#
# "x, y"
#
# @return [String] Point as comma separated String
#
def to_s
"#{x}, #{y}"
end
#
# Point inverse/reverse
#
# MongoDB: "x, y"
# Reverse: "y, x"
#
# @return [Array] Point reversed: "y, x"
#
def reverse
[y, x]
end
#
# Distance calculation methods. Thinking about not using it
# One needs to choose and external lib. GeoRuby or RGeo
#
# Return the distance between the 2D points (ie taking care
# only of the x and y coordinates), assuming the points are
# in projected coordinates. Euclidian distance in whatever
# unit the x and y ordinates are.
# def euclidian_distance(point)
# Math.sqrt((point.x - x)**2 + (point.y - y)**2)
# end
# # Spherical distance in meters, using 'Haversine' formula.
# # with a radius of 6471000m
# # Assumes x is the lon and y the lat, in degrees (Changed
# in version 1.1).
# # The user has to make sure using this distance makes sense
# (ie she should be in latlon coordinates)
# def spherical_distance(point,r=6370997.0)
# dlat = (point.lat - lat) * DEG2RAD / 2
# dlon = (point.lon - lon) * DEG2RAD / 2
# a = Math.sin(dlat)**2 + Math.cos(lat * DEG2RAD) *
# Math.cos(point.lat * DEG2RAD) * Math.sin(dlon)**2
# c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a))
# r * c
# end
class << self
#
# Database -> Object
# Get it back
def demongoize(obj)
obj && new(*obj)
end
#
# Object -> Database
# Send it to MongoDB
def mongoize(obj)
case obj
when Point then obj.mongoize
when String then from_string(obj)
when Array then from_array(obj)
when Hash then from_hash(obj)
when NilClass then nil
else
return obj.to_xy if obj.respond_to?(:to_xy)
raise 'Invalid Point'
end
end
# Converts the object that was supplied to a criteria
# into a database friendly form.
def evolve(obj)
case obj
when Point then obj.mongoize
else obj
end
end
private
#
# Sanitize a `Point` from a `String`
#
# Makes life easier:
# "" -> []
# "1, 2" -> [1.0, 2.0]
# "1.1 2.2" -> [1.1, 2.2]
#
# @return (Array)
#
def from_string(str)
return nil if str.empty?
str.split(/,|\s/).reject(&:empty?).map(&:to_f)
end
#
# Sanitize a `Point` from an `Array`
#
# Also makes life easier:
# [] -> []
# [1,2] -> [1.0, 2.0]
#
# @return (Array)
#
def from_array(array)
return nil if array.empty?
array.flatten[0..1].map(&:to_f)
end
#
# Sanitize a `Point` from a `Hash`
#
# Uses Mongoid::Geospatial.lat_symbols & lng_symbols
#
# Also makes life easier:
# {x: 1.0, y: 2.0} -> [1.0, 2.0]
# {lat: 1.0, lon: 2.0} -> [1.0, 2.0]
# {lat: 1.0, long: 2.0} -> [1.0, 2.0]
#
# Throws error if hash has less than 2 items.
#
# @return (Array)
#
def from_hash(hsh)
raise 'Hash must have at least 2 items' if hsh.size < 2
[from_hash_x(hsh), from_hash_y(hsh)]
end
def from_hash_y(hsh)
v = (Mongoid::Geospatial::Config::Point.y & hsh.keys).first
return hsh[v].to_f if !v.nil? && hsh[v]
raise "Hash must contain #{Mongoid::Geospatial::Config::Point.y.inspect}"
end
def from_hash_x(hsh)
v = (Mongoid::Geospatial::Config::Point.x & hsh.keys).first
return hsh[v].to_f if !v.nil? && hsh[v]
raise "Hash must contain #{Mongoid::Geospatial::Config::Point.x.inspect}"
end
end # << self
end # Point
end # Geospatial
end # Mongoid