Google Maps

Google Maps is a free web-based mapping service provided by Google. It provides a map that can be navigated by dragging the mouse across it and zoomed in and out using the mouse wheel or a zoom bar. It has three forms of views—map, satellite and a hybrid of map and satellite. Google Maps is coded almost entirely in JavaScript and XML and Google provides a free JavaScript API library that allows developers to integrate Google Maps into their own applications. Google Maps APIs also provide geocoding capabilities, that is, they able to convert addresses to longitude and latitude coordinates.

We will be using two parts of Google Maps:

Yahoo Maps

Yahoo Maps is a free mapping service provided by Yahoo. Much like Google Maps it also provides a map that is navigable in a similar way and also provides an extensive set of APIs. Yahoo's mapping APIs range from simply including the map directly from the Yahoo Maps website, to Flash APIs and JavaScript APIs. Yahoo Maps also provides geocoding services. We will be using Yahoo Maps geocoding services as part of GeoKit's API to geocode addresses.

Geocoder.us

Geocoder.us is a website that provides free geocoding of addresses and intersections in the United States. It relies on Geo::Coder::US, a Perl module available for download from the CPAN and derives its data from the TIGER/Line data set, public-domain data from the US Census Bureau. Its reliability is higher in urban areas but lower in the other parts of the country. We will be using Geocoder.us as part of GeoKit's API to geocode addresses.

Geocoder.ca

Geocoder.ca is a website that provides free geocoding of addresses in the United States and Canada. Like Geocoder.us. it uses data from TIGER/Line but in addition, draws data from GeoBase, the Canadian government-related initiative that provides geospatial information on Canadian territories. We will be using Geocoder.ca as part of GeoKit's API to geocode addresses.

Hostip.info

Hostip.info is a website that provides free geocoding of IP addresses. Hostip.info offers an HTTP-based API as well as its entire database for integration at no cost. We will be using Hostip.info as part of GeoKit's API to geocode IP addresses.

GeoKit

GeoKit is a Rails plugin that enables you to build location-based applications. For this chapter we will be using GeoKit for its geocoding capabilities in two ways:

GeoKit is a plugin to your Rails application so installing it means more or less copying the source files from the GeoKit Subversion repository and running through an installation script that adds certain default parameters in your environment.rb file.

To install the GeoKit, go to your Rails application folder and execute this at the command line:

$./script/plugin install svn://rubyforge.org/var/svn/geokit/trunk

This will copy the necessary files to your RAILS_ROOT/vendor/plugins folder and run the install.rb script.

# Include your application configuration below # These defaults are used in GeoKit::Mappable.distance_to and in acts_as_mappable
GeoKit::default_units = :miles
GeoKit::default_formula = :sphere
# This is the timeout value in seconds to be used for calls to the geocoder web
# services. For no timeout at all, comment out the setting. The timeout unit is in seconds.
# GeoKit::Geocoders::timeout = 3
# These settings are used if web service calls must be routed through a proxy.
# These setting can be nil if not needed, otherwise, addr and port must be filled in at a minimum. If the proxy requires authentication, the username and password can be provided as well.
GeoKit::Geocoders::proxy_addr = nil
GeoKit::Geocoders::proxy_port = nil
GeoKit::Geocoders::proxy_user = nil
GeoKit::Geocoders::proxy_pass = nil
# This is your yahoo application key for the Yahoo Geocoder
# See http://developer.yahoo.com/faq/index.html#appid and http://developer.yahoo.com/maps/rest/V1/geocode.html
GeoKit::Geocoders::yahoo = <YOUR YAHOO APP ID>
# This is your Google Maps geocoder key.
# See http://www.google.com/apis/maps/signup.html and http://www.google.com/apis/maps/documentation/#Geocoding_Examples
GeoKit::Geocoders::google = <YOUR GOOGLE MAPS KEY>
# This is your username and password for geocoder.us
# To use the free service, the value can be set to nil or false. For usage tied to an account, the value should be set to username:password.
# See http://geocoder.us and http://geocoder.us/user/signup
GeoKit::Geocoders::geocoder_us = false
# This is your authorization key for geocoder.ca.
# To use the free service, the value can be set to nil or false. For usage tied to an account, set the value to the key obtained from Geocoder.ca
# See http://geocoder.ca and http://geocoder.ca/?register=1
GeoKit::Geocoders::geocoder_ca = false
# This is the order in which the geocoders are called in a failover scenario
# If you only want to use a single geocoder, put a single symbol in the array.
# Valid symbols are :google, :yahoo, :us, and :ca
# Be aware that there are Terms of Use restrictions on how you can use the various geocoders. Make sure you read up on relevant Terms of Use for each geocoder you are going to use.
GeoKit::Geocoders::provider_order = [:google,:yahoo]

GeoKit::Geocoders::provider_order = [:google,:yahoo]

YM4R/GM

YM4R/GM is another Rails plugin, one that facilitates the use of Google Maps APIs. We will be using YM4R/GM to display the kiosk locations on a customized Google Map. This API essentially wraps around the Google Maps APIs but also provides additional features to make it easier to use from Ruby. To install it, go to your Rails application folder and execute this at the command line:

$./script/plugin install svn://rubyforge.org/var/svn/ym4r/Plugins/GM/trunk/ym4r_gm

During the installation, the JavaScript files found in the RAILS_ROOT/vendors/plugin/javascript folder will be copied to the RAILS_ROOT/public/javascripts folder.

A gmaps_api_key.yml file is also created in the RAILS_ROOT/config folder. This file is a YAML representation of a hash, like the database.yml file in which you can set up a test, development, and production environment. This is where you will put in your Google Maps API key (in addition to the environment.rb you have changed earlier).

For your local testing you will not need to change the values but once you deploy this in production on an Internet site you will need to put in a real value according to your domain.