Class: MapPLZ::GeoItem

Inherits:
Hash
  • Object
show all
Defined in:
lib/mapplz.rb

Overview

internal map object record

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db = nil) ⇒ GeoItem

Returns a new instance of GeoItem.



691
692
693
694
695
696
 
# File 'lib/mapplz.rb', line 691

def initialize(db = nil)
  db = { type: 'array', client: nil } if db.nil?
  @db = db
  @db_type = db[:type]
  @db_client = db[:client]
end

Class Method Details

.centroid(geo_item) ⇒ Object 



843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
 
# File 'lib/mapplz.rb', line 843

def self.centroid(geo_item)
  # generate centroid if possible and not already existing
  if geo_item.key?(:path) && !geo_item.centroid
    coordinates = geo_item[:path].clone

    # centroid calculation from https://code.google.com/p/tokland/source/browse/trunk/centroid
    consecutive_pairs = (coordinates + [coordinates.first]).each_cons(2)
    area = 0.5 * consecutive_pairs.map do |(x0, y0), (x1, y1)|
      (x0 * y1) - (x1 * y0)
    end
    area.inject(:+)

    consecutive_pairs.map! do |(x0, y0), (x1, y1)|
      cross = (x0 * y1 - x1 * y0)
      [(x0 + x1) * cross, (y0 + y1) * cross]
    end
    (center_lat, center_lng) = consecutive_pairs.transpose.map do |cs|
      cs.inject(:+) / (6 * area)
    end

    geo_item[:centroid] = Digest::SHA256.digest(geo_item[:path].to_s)
    geo_item[:lat] = center_lat
    geo_item[:lng] = center_lng
  end
end

Instance Method Details

#centroid ⇒ Object 



802
803
804
805
806
 
# File 'lib/mapplz.rb', line 802

def centroid
  # verify up-to-date centroid exists
  path_hash = Digest::SHA256.digest(self[:path].to_s)
  (key?(:path) && key?(:centroid) && self[:centroid] == path_hash)
end

#delete_item ⇒ Object 



727
728
729
730
731
732
733
734
735
736
737
738
739
740
 
# File 'lib/mapplz.rb', line 727

def delete_item
  if @db_type == 'array'
    keys.each do |key|
      delete(key)
    end
  elsif @db_type == 'mongodb'
    # update record in database
    @db[:client].remove(_id: BSON::ObjectId(self[:_id]))
  elsif @db_type == 'postgis'
    @db_client.exec("DELETE FROM mapplz WHERE id = #{self[:id]}")
  elsif @db_type == 'spatialite'
    @db_client.execute("DELETE FROM mapplz WHERE id = #{self[:id]}")
  end
end

#distance_from(user_geo) ⇒ Object 



808
809
810
811
812
813
814
 
# File 'lib/mapplz.rb', line 808

def distance_from(user_geo)
  GeoItem.centroid(self)
  user_geo = MapPLZ.standardize_geo(user_geo)[0]
  GeoItem.centroid(user_geo)

  Geokdtree::Tree.distance([user_geo[:lat], user_geo[:lng]], [self[:lat], self[:lng]])
end

#inside?(user_geo) ⇒ Boolean

Returns:

  • (Boolean) 


816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
 
# File 'lib/mapplz.rb', line 816

def inside?(user_geo)
  GeoItem.centroid(self)

  # accept [point1, point2, point3, point1] as a polygon search area
  if user_geo.is_a?(Array) && user_geo[0].is_a?(Array) && !user_geo[0][0].is_a?(Array)
    user_geo = [user_geo]
  end

  user_geo = MapPLZ.standardize_geo(user_geo)[0]
  path_pts = user_geo[:path]
  path_pts = path_pts[0] if user_geo[:type] == 'polygon'

  # point in polygon from http://jakescruggs.blogspot.com/2009/07/point-inside-polygon-in-ruby.html
  c = false
  i = -1
  j = path_pts.size - 1
  while (i += 1) < path_pts.size
    if (path_pts[i][0] <= self[:lat] && self[:lat] < path_pts[j][0]) || (path_pts[j][0] <= self[:lat] && self[:lat] < path_pts[i][0])
      if self[:lng] < (path_pts[j][1] - path_pts[i][1]) * (self[:lat] - path_pts[i][0]) / (path_pts[j][0] - path_pts[i][0]) + path_pts[i][1]
        c = !c
      end
    end
    j = i
  end
  c
end

#save! ⇒ Object 



698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
 
# File 'lib/mapplz.rb', line 698

def save!
  # update record in database
  if @db_type == 'mongodb'
    save_obj = clone
    save_obj.delete(:_id)
    save_obj.delete(:lat)
    save_obj.delete(:lng)
    save_obj.delete(:path)
    save_obj.delete(:centroid)
    save_obj.delete(:type)
    save_obj[:geo] = JSON.parse(to_geojson)['geometry']
    @db[:client].update({ _id: BSON::ObjectId(self[:_id]) }, save_obj)
  elsif @db_type == 'postgis'
    geojson_props = (JSON.parse(to_geojson)['properties'] || {})
    @db_client.exec("UPDATE mapplz SET geom = ST_GeomFromText('#{to_wkt}'), properties = '#{geojson_props.to_json}' WHERE id = #{self[:id]}") if @db_type == 'postgis'
  elsif @db_type == 'spatialite'
    updaters = []
    keys.each do |key|
      next if [:id, :lat, :lng, :path, :type, :centroid].include?(key)
      updaters << "#{key} = '#{self[key]}'" if self[key].is_a?(String)
      updaters << "#{key} = #{self[key]}" if self[key].is_a?(Integer) || self[key].is_a?(Float)
    end
    updaters << "geom = AsText('#{to_wkt}')"
    if updaters.length > 0
      @db_client.execute("UPDATE mapplz SET #{updaters.join(', ')} WHERE id = #{self[:id]}")
    end
  end
end

#to_geojson ⇒ Object 



759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
 
# File 'lib/mapplz.rb', line 759

def to_geojson
  if key?(:properties)
    property_list = { properties: self[:properties] }
  else
    property_list = clone
    property_list.delete(:lat)
    property_list.delete(:lng)
    property_list.delete(:path)
    property_list.delete(:type)
    property_list.delete(:centroid)
  end

  output_geo = {
    type: 'Feature',
    properties: property_list
  }

  if self[:type] == 'point'
    # point
    output_geo[:geometry] = {
      type: 'Point',
      coordinates: [self[:lng], self[:lat]]
    }
  elsif self[:type] == 'polyline'
    # line
    output_geo[:geometry] = {
      type: 'LineString',
      coordinates: MapPLZ.flip_path(self[:path])
    }
  elsif self[:type] == 'polygon'
    # polygon
    rings = self[:path].clone
    rings.map! do |ring|
      MapPLZ.flip_path(ring)
    end
    output_geo[:geometry] = {
      type: 'Polygon',
      coordinates: rings
    }
  end
  output_geo.to_json
end

#to_wkt ⇒ Object 



742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
 
# File 'lib/mapplz.rb', line 742

def to_wkt
  if self[:type] == 'point'
    geom = "POINT(#{self[:lng]} #{self[:lat]})"
  elsif self[:type] == 'polyline'
    linestring = self[:path].map do |path_pt|
      "#{path_pt[1]} #{path_pt[0]}"
    end
    geom = "LINESTRING(#{linestring.join(', ')})"
  elsif self[:type] == 'polygon'
    linestring = self[:path][0].map do |path_pt|
      "#{path_pt[1]} #{path_pt[0]}"
    end
    geom = "POLYGON((#{linestring.join(', ')}))"
  end
  geom
end