lol

postgis-crash-course.rb

file = open(kml_path)
doc = Nokogiri::XML(file.read)

corridors = doc.css('kml Document Placemark').map { |placemark|
  next unless corridor?(placemark)
  create_polygon(placemark)
}

def factory
  @factory ||= Locality.new.latlng.factory
end

def create_polygon(kml)
  coords_str = kml.at_css('Polygon outerBoundaryIs LinearRing coordinates').text
  coords_3d = coords_str.tr(' ', ',').split(',') # originally "x,y,z x,y,z"
  coords_3d = coords_3d.map &:to_f # remove z axis
  coords = coords_3d.reject { |flt| flt == 0.0 } # remove z axis
  points = coords.each_slice(2).map { |lng_lat| factory.point *lng_lat }
  linear_ring = factory.linear_ring points
  factory.polygon(linear_ring)
end

# migration
class AddLatlngToLocality < ActiveRecord::Migration
  def change
    add_column :localities, :latlng, :point, geographic: true, default: 'POINT(0 0)'
    add_index :localities, :latlng, using: :gist
  end
end