This document provides an introduction to geospatial Ruby libraries. It begins with three geography lessons: vector data types and OGC simple features, spatial relationships, and spatial reference systems. It then discusses several geospatial Ruby libraries including GEOS, GeoRuby, RGeo, and spatial database adapters. It also covers location-based APIs and services like Twitter, Instagram, Yelp, and Fusion Tables that can be used to generate geospatial data. Finally, it discusses the GeoCommons gem and platform for geospatial data storage, analysis, and visualization.

1. +
OPEN GEOSPATIAL
RUBY LIBRARIES
Christopher Helm - GeoIQ
http://geocommons.com

2. The Plan
• Keep it simple
• Introduce you to geospatial
• Dive into a few example libs
• Demo some code!

3. THIS TALK...
...is for (~Ruby) geospatial newcomers

4. STAYING SIMPLE
GeoSpatial is a deep subject
we’re barely skimming the surface

5. WHAT IS GEOSPATIAL?

6. LOCATION

7. DATA

8. ANALYSIS

9. VISUALIZATION

10. WHY DOES THIS MATTER?
location is everywhere :)

11. GEOGRAPHY LESSON 1:
Vector Data Types
Points Lines Polygons

12. GEOGRAPHY LESSON 1:
OGC’s Simple Features
POINT(30, 40)
LINESTRING(30 10, 10 30, 40 40)
POLYGON(30 10, 10 20, 20 40, 40 40, 30 10)
MULTI*

13. GEOGRAPHY LESSON 2:
Spatial Relationships
Buffers
Intersections
Clips
Dissolves
Unions
Aggregation
etc...

14. GEOGRAPHY LESSON 2:
Spatial Relationships
Buffers

15. GEOGRAPHY LESSON 2:
Spatial Relationships
Dissolves

16. GEOGRAPHY LESSON 2:
Spatial Relationships
Clips Intersections

17. GEOGRAPHY LESSON 2:
Spatial Relationships
Spatial Aggregation

18. GEOGRAPHY LESSON 3:
Spatial Reference Systems
http://www.cartogrammar.com/blog/accidental-map-projections/

19. GEOGRAPHY LESSON 3:
Spatial Reference Systems
Plate Carrée, Geographic, or un-projected

20. GEOGRAPHY LESSON 3:
Spatial Reference Systems
Spherical Mercator (Web Mercator)

21. SOME GEOSPATIAL LIBS
•2 categories of libraries
• 1. Ruby based GeoSpatial Data Libraries
• 2. Ruby bindings location-aware APIs & services

22. GEOS
http://trac.osgeo.org/geos/
Geometry Engine - Open Source (GEOS)
A C++ port of the Java Topology Suite
Simple Features and spatial operators

23. GEOS
require 'geos'
@reader = Geos::WktReader.new()
# Create points
p1 = @reader.read(‘POINT(1, 2)’)
p2 = @reader.read(‘POINT(3, 4)’)
p3 = @reader.read(‘POINT(5, 2)’)
p2
y
p1 p3
x

24. GEOS
# Create a more complex shapes
line1 = @reader.read(‘LINESTRING(1 2, 3 4, 5 2)’)
polygon = @reader.read(‘POLYGON(1 2, 3 4, 5 2, 1 2)’)
line2 = @reader.read('LINESTRING(1 4, 4 1)')
line1 Polygon
line2

25. GEOS
# Perform geometric operations and calculations
line3 = polygon.intersection(line2)
dist = line3.distance(p3)
line2
dist
line3 p3
line3

26. GEOS
# new point
p4 = @reader.read(‘POINT(2.5, 3.5)’)
# create a buffer on p4
buffer = p4.buffer(2)
# now test against the buffer
buffer.contains?(p1) # false
buffer.contains?(p2) # true
buffer.touches?(p3.buffer(1)) # true
p2
p4
p1 p3
buffer

27. GEORUBY
http://rubyforge.org/projects/georuby/
A Library for working with geometric data types in Ruby
follows the OGC’s Simple Features Spec
Think: Point, Lines, and Polygons
Also data formatters / parsers
(KML to Well Known Text)

28. SPATIAL ADAPTER
https://github.com/fragility/spatial_adapterxt
Adapter for ActiveRecord
Handles spatial datatypes coming from:
PostGreSQL (via PostGIS)
&
MySQL (via its spatial ext.)

29. RGEO
http://virtuoso.rubyforge.org/rgeo/
Geospatial datatypes in Ruby
Standard Spatial analysis operations:
(buffers, intersections, distances, etc)
Data format conversions
Flexible - gem and active-record adapter

30. RUBY GEOCODER
http://www.rubygeocoder.com/
Full featured geocoder for Ruby
Gem and Rails Plugin
Converts addresses and IPs in lat/lon coordinates
configurable to work with any service
Also checkout geokit: http://geokit.rubyforge.org/

31. RUBY GEOCODER
http://www.rubygeocoder.com/
require ‘geocoder’
# look up coordinates of some location
Geocoder.coordinates("25 Main St, Cooperstown, NY")
=> [42.700149, -74.922767]
# distance between Eiffel Tower and Empire State Building
Geocoder::Calculations.distance_between([47.858205,2.294359],
[40.748433,-73.985655])
=> 3619.77359999382
# find the geographic coordinates for an IP address
Geocoder.coordinates("71.166.236.36")
=> [38.6485, -77.3108]

32. DATABASES
PostgreSQL / Postgis
MySQL
MongoDB
Couch...DB....base (via GeoCouch)

33. POSTGRESQL
PostGIS - spatial extension
Uses GEOS for spatial operations

34. ACTIVERECORD POSTGIS
https://github.com/dazuma/activerecord-postgis-adapter
create_table :my_spatial_table do |t|
t.column :shape, :geometry # or t.geometry :shape
t.line_string :path, :srid => 3785
t.point :latlon, :geographic => true
end
change_table :my_spatial_table do |t|
t.index :latlon, :spatial => true
end
# querying
rec = MySpatialTable.where(:latlon => 'POINT(-122 47)').first

35. MONGODB
require 'mongo'
db = Mongo::Connection.new("localhost", 27017).db("mydb")
auth = db.authenticate(my_user_name, my_password)
coll = db.collection("testCollection")
coll.find("i" => 71).each { |row| puts row.inspect }

36. MONGODB
# Spatial indexes / queries
coll.create_index([["loc", Mongo::GEO2D]])
coll.find({"loc" => {"$near" => [50, 50]}}, {:limit => 20}).each
do |p|
puts p.inspect
end

37. MONGODB
box = [[40.73083, -73.99756], [40.741404, -73.988135]]
coll.find({"loc" : {"$within" : {"$box" : box}}})
center = [50, 50]
radius = 10
coll.find({"loc" : {"$within" : {"$center" : [center, radius]}}})

38. SOCIAL MEDIA APIS

39. TWEETSTREAM
https://github.com/intridea/tweetstream
Simple wrapper to the Twitter Streaming API
Can search via tags or locations (via bboxes)
Good way to generate geospatial data/content

40. TWEETSTREAM
require 'rubygems'
require 'tweetstream'
# Use 'track' to track a list of single-word keywords
TweetStream::Client.new('username','password').track('term1',
'term2') do |status|
puts "#{status.text}"
end
# track tweets within a bbox
TweetStream::Client.new('username','password').locations(‘-122.75,
36.8,-121.75,37.8’) do |status|
puts "#{status.text}"
end

41. INSTAGRAM
https://github.com/Instagram/instagram-ruby-gem
Wrapper to the Instragram’s photo sharing API
Allows for spatial searching via lat/lon
very similar to the Flick’r API

42. CARTAGR.AM
bloom.io

43. INSTAGRAM
require "instagram"
# All methods require authentication
Instagram.configure do |config|
config.client_id = YOUR_CLIENT_KEY
config.access_token = YOUR_ACCESS_TOKEN
end
# Get a list of media at a given location
puts Instagram.location_recent_media(514276)
# Get a list of media close to a given latitude and longitude
puts Instagram.media_search("37.7808851,-122.3948632")

44. YELP!
http://github.com/shaper/yelp
Location based lookup for business reviews
Highly local listing accessed in variety of geospatial ways
another way to create some geospatial data/content

45. YELP!

46. YELP!
# create a new client
client = Yelp::Client.new
# do an address-based search for cream puffs nearby
request = Yelp::Review::Request::Location.new(
:address => '650 Mission St',
:city => 'San Francisco',
:state => 'CA',
:radius => 2,
:term => 'cream puffs',
:yws_id => 'YOUR_YWSID_HERE')
response = client.search(request)

47. YELP!
# a location-based search for ice cream or donut shops in SF
request = Yelp::Review::Request::Location.new(
:city => 'San Francisco',
:state => 'CA',
:category => [ 'donuts', 'icecream' ],
:yws_id => 'YOUR_YWSID_HERE')
response = client.search(request)
# a neighborhood name lookup for a geo-location point
request = Yelp::Neighborhood::Request::GeoPoint.new(
:latitude => 37.782093,
:longitude => -122.483230,
:yws_id => 'YOUR_YWSID_HERE')
response = client.search(request)

48. DATA & ANALYSIS APIS
Fusion Tables

49. SIMPLEGEO
https://github.com/simplegeo/simplegeo-ruby
API for adding geospatial capabilities to apps
Access POIs, Locational Context, and personal data
Emphasis on speed, simplicity, and flexibility

50. SIMPLEGEO
Context API
# grab the context of a lat/lon
SimpleGeo::Client.get_context(37.772445,-122.405913)
# context
SimpleGeo::Client.get_context_by_address("41 Decatur St, San
Francisco, CA 94103")
SimpleGeo::Client.get_context_ip("184.84.228.110")

51. SIMPLEGEO
Places API
SimpleGeo::Client.get_places(37.772445, -122.405913)
options = {'q'=>'Starbucks', 'category'=>'Coffee & Tea',
'radius'=>5}
SimpleGeo::Client.get_places(37.772445, -122.405913, options)
address = "41 Decatur St, San Francisco, CA"
options = {'radius' => 1}
SimpleGeo::Client.get_places_by_address(address, options)
ip = '173.164.219.53'
SimpleGeo::Client.get_places_by_ip(ip)

52. FUSION TABLES
https://github.com/tokumine/fusion_tables
Direct access to Google’s Fusion Tables API
Full SQL interface or OO query interface
Easy integration to other Google services
(maps, earth, viz.)
Easy storage/retrieve of geospatial data

53. FUSION TABLES
require 'fusion_tables'
# Connect to service
@ft = GData::Client::FusionTables.new
@ft.clientlogin(username, password)
# 1. SQL interface
@ft.execute "SHOW TABLES"
@ft.execute "INSERT INTO #{my_table_id} (name, geo) VALUES
('tokyo', '35.6894 139.6917');"
@ft.execute "SELECT count() FROM #{my_table_id};"

54. GEOCOMMONS
http://geocommons.com
Open Data Storage, Analysis, and Visualization
Strong emphasis on usability
Build complex geospatial workflows
Share data visualizations on the web

55. GEOCOMMONS
CSV
Easy Spatial Visualization / Analytics
SHP
JSON
WMS
Maps & Viz
Analytics

56. GEOCOMMONS GEM
API
GeoCommons
Mgmt Analysis
Visualization
geoiq-
ruby

57. GEOCOMMONS GEM
finding data...
# create a client
@geoiq = Geoiq.client("http://geocommons.com", "user", "password")
# search for tags
@geoiq.search("tag:economics")
# Search for data in a location
@geoiq.search("points",{:bbox => ‘-87.2,33.4,-75.9,38.4', :limit=>
10})

58. GEOCOMMONS GEM
getting data...
# get dataset and features
dataset = geoiq.dataset.find(1348)
features = dataset.features
# get features with a custom filter
filtered_features = @dataset.features({"filter[PERIMETER][][max]"
=> 0.3})
bbox_filtered_features = @dataset.features({:bbox =>
'-87.2,33.4,-75.9,38.4'})

59. GEOCOMMONS
uploading data...
# Upload CSV
csv_file = 'data/sculptures.csv'
@dataset = @geoiq.dataset.csv_upload(csv_file, {:title =>"garden
sculptures"})
# Upload SHP
@dataset = @geoiq.dataset.shp_upload("data/simple.shp", "data/
simple.dbf", "data/simple.shx")
# Upload by URL (type = csv,kml,rss,wms,tile)
@dataset = @geoiq.dataset.url_upload("http://geothings.net/geoiq/
simple_testing.csv", {:type => "csv"})

60. GEOCOMMONS
create new datasets...
# Create a new overlay
data = {‘title’ => ‘My Overlay’, ‘attributes’ => {‘attr1’ => ...}}
overlay = @geoiq.dataset.create(data)
# add features to the overlay
features = {features => [{‘type’ => ‘Point’, ‘coordinates’ =>
[0,0]},{...}]}
@geoiq.dataset.update(id, features)

61. GEOCOMMONS
create new visualizations...
# Create a new map
map = @geoiq.map(:title => "my empty map")
@geoiq_map = map.create
# get a map and it's layers
@map = @geoiq.map.find(239)
layer_titles = @map.layers.map{ |l| l['title']}
# add a dataset to a map as a new layer
@map.add_layer(1466)
#deleting map or dataset
@map.delete
@dataset.delete

62. PUTTING IT TOGETHER

63. SOME EXAMPLES...
...THEN QUESTIONS

64. Code Samples from this talk:
https://github.com/chelm/OSCON-Ruby-GeoSpatial-Intro