Class: MetaCartaGeoParser

Inherits:
RCRest
  • Object
show all
Defined in:
lib/metacarta_geoparser.rb

Overview

Library for looking up coordinates with MetaCarta’s GeoParser API.

labs.metacarta.com/GeoParser/documentation.html

Defined Under Namespace

Classes: AddressError, Error, Location

Constant Summary collapse

VERSION = 
'1.0.2'

Instance Method Summary collapse

Constructor Details

#initialize ⇒ MetaCartaGeoParser

:nodoc:



22
23
24
 
# File 'lib/metacarta_geoparser.rb', line 22

def initialize # :nodoc:
  @url = URI.parse 'http://labs.metacarta.com/GeoParser/'
end

Instance Method Details

#check_error(xml) ⇒ Object

:nodoc:

Raises:



44
45
46
 
# File 'lib/metacarta_geoparser.rb', line 44

def check_error(xml) # :nodoc:
  raise AddressError, 'bad location' unless xml.elements['Locations/Location']
end

#locate(place) ⇒ Object

Locates place and returns a Location object.



29
30
31
32
 
# File 'lib/metacarta_geoparser.rb', line 29

def locate(place)
  locations, = get nil, :q => place
  return locations.first
end

#locations(place) ⇒ Object

Retrieve all locations matching place.

Returns an Array of Location objects and a pair of coordinates that will surround them.



40
41
42
 
# File 'lib/metacarta_geoparser.rb', line 40

def locations(place)
  get nil, :loc => place
end

#make_url(method, params) ⇒ Object

:nodoc:



48
49
50
51
52
 
# File 'lib/metacarta_geoparser.rb', line 48

def make_url(method, params) # :nodoc:
  params[:output] = 'locations'

  super method, params
end

#parse_response(xml) ⇒ Object

:nodoc:



54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
 
# File 'lib/metacarta_geoparser.rb', line 54

def parse_response(xml) # :nodoc:
  locations = []

  xml.elements['/Locations'].each do |l|
    next if REXML::Text === l or l.name == 'ViewBox'
    location = Location.new

    location.viewbox = viewbox_coords l.elements['ViewBox/gml:Box/gml:coordinates']

    location.name = l.attributes['Name']
    location.type = l.attributes['Type']
    population = l.attributes['Population'].to_i
    location.population = population > 0 ? population : nil
    location.hierarchy = l.attributes['Hierarchy']

    coords = l.elements['Centroid/gml:Point/gml:coordinates'].text.split ','
    location.latitude = coords.last.to_f
    location.longitude = coords.first.to_f

    confidence = l.elements['Confidence']
    location.confidence = confidence.text.to_f if confidence

    locations << location
  end

  query_viewbox = xml.elements['/Locations/ViewBox/gml:Box/gml:coordinates']

  return locations, viewbox_coords(query_viewbox)
end

#viewbox_coords(viewbox) ⇒ Object

Turns a element containing a pair of coordinates into a pair of coordinate Arrays.



88
89
90
91
92
 
# File 'lib/metacarta_geoparser.rb', line 88

def viewbox_coords(viewbox) # :nodoc:
  return viewbox.text.split(' ').map do |coords|
    coords.split(',').map { |c| c.to_f }
  end
end