使用地理編碼器gem和RGeo的PostGIS數據庫對地址進行地理編碼

Question

我正在嘗試使用地址解析器gem來查找地址和坐標。 我希望它與PostGIS空間數據庫和RGeo gem一起使用，后者使用POINT功能而不是分別保存緯度和經度值。 因此，我嘗試研究模型以將地址解析器的結果保存到RGeo POINT功能中：

class Location < ActiveRecord::Base
  attr_accessible :latlon, :name, :address
  set_rgeo_factory_for_column(:latlon, RGeo::Geographic.spherical_factory(:srid => 4326))

  geocoded_by :name_and_address do |obj, results|
    if geo = results.first
      obj.latlon = Location.rgeo_factory_for_column(:latlon).point(geo.longitude, geo.latitude)
    end
  end

  after_initialize :init
  after_validation :geocode


  def init
    self.latlon ||= Location.rgeo_factory_for_column(:latlon).point(0, 0)
  end

  def latitude
    self.latlon.lat
  end

  def latitude=(value)
    lon = self.latlon.lon
    self.latlon = Location.rgeo_factory_for_column(:latlon).point(lon, value)
  end

  def longitude
    self.latlon.lon
  end

  def longitude=(value)
    lat = self.latlon.lat
    self.latlon = Location.rgeo_factory_for_column(:latlon).point(value, lat)
  end

  def name_and_address
    "#{self.name}, #{self.address}"
  end

end

在Rails控制台中，我現在可以執行以下操作：

test = Location.new(name: "Eiffel Tower") // => #<Location id: nil, name: "Eiffel Tower", latlon: #<RGeo::Geographic::SphericalPointImpl:0x81579974 "POINT (0.0 0.0)">, created_at: nil, updated_at: nil, address: nil>
test.geocode    //  => #<RGeo::Geographic::SphericalPointImpl:0x81581ac0 "POINT (2.294254 48.858278)">

精彩！ 但是，當我想保存測試位置，從而觸發:geocode的:after_validation調用時，出現錯誤：

NoMethodError: undefined method `lon' for nil:NilClass
    from /Users/sg/rails-projects/geo_rails_test/app/models/location.rb:24:in `latitude='
    from /Users/sg/rails-projects/geo_rails_test/app/models/location.rb:7:in `block in <class:Location>'
    from /Users/sg/.rvm/gems/ruby-1.9.3-p194/gems/geocoder-1.1.2/lib/geocoder/stores/base.rb:108:in `call'
    from /Users/sg/.rvm/gems/ruby-1.9.3-p194/gems/geocoder-1.1.2/lib/geocoder/stores/base.rb:108:in `do_lookup'
    from /Users/sg/.rvm/gems/ruby-1.9.3-p194/gems/geocoder-1.1.2/lib/geocoder/stores/active_record.rb:278:in `geocode'
    from /Users/sg/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:405:in `_run__1498365873506454431__validation__51840359655181017__callbacks'
    [...]

似乎地理編碼回調刪除了RGeo對象，因此它的內置方法以及我的getter和setter方法不再可用。 為什么？ 有任何想法嗎？

Answer 1

這是流血的錯字...

有用。 我將其保留，也許其他人有相同的問題或更好的解決方案...

我還添加了reverse_geocode案例。

現在看它能做什么：

1.9.3p194 :310 > loc = Location.new(name: "Vatikan")
 => #<Location id: nil, name: "Vatikan", latlon: #<RGeo::Geographic::SphericalPointImpl:0x8148add8 "POINT (0.0 0.0)">, created_at: nil, updated_at: nil, address: nil> 
1.9.3p194 :311 > loc.save
   (0.2ms)  BEGIN
  SQL (0.6ms)  INSERT INTO "locations" ("address", "created_at", "latlon", "name", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["address", "Via Pio X, 00120, Vatican City"], ["created_at", Sat, 17 Nov 2012 19:26:59 UTC +00:00], ["latlon", #<RGeo::Geographic::SphericalPointImpl:0x81570554 "POINT (12.453389 41.902916)">], ["name", "Vatikan"], ["updated_at", Sat, 17 Nov 2012 19:26:59 UTC +00:00]]
   (0.9ms)  COMMIT
 => true 

我喜歡這個！ :-)