Google Maps API: Raining Cats and Dogs

  • December 12, 2013 · 7:00 PM
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MEET MATT HOLTOM: Matt is an experienced hacker, active firefighter and creator of Toronto Fire Calls. He's also founder of Code & Iron. Matt will kickoff this meetup with a story of how he built Toronto Fire Calls to provide a real-time display of active emergencies across Toronto.

VISUALIZATION: A live-coding session where you will learn how to geocode a dataset and map it using Ruby and the Google Maps API. This event is for developers who want to explore different ways of visualizing geographic data. Some background in Ruby is helpful.

We will be using Ruby and the Google Maps API to analyze the Toronto Cats and Dogs dataset by postal code (from Open Data Toronto).


Pro-Talk [30 min]: Matt Holtom shares how he turned this raw fire data into this beautiful interactive map. He will cover the fundamentals of geocoding, challenges encountered, feature tradeoffs and overall what he learned from the project and technology used.

Live Coding Tutorial [90 min]: As a group, we will modify a sample project created by Matt to visually answer the following questions about the Toronto Cats & Dogs dataset:

1. Which area of Toronto have the most cats and the most dogs?

2. Which area of Toronto has the most dog lovers and cat lovers (the biggest difference between number of dogs and cats)?


Please add the DVTO4 Vagrant Image prior to the meetup (see link below). The Vagrant Image contains a prepackaged Rails and Postgres environment that's ready to go.

Setup instructions:


This session is intended for people who are interested in exploring different ways of visualizing geographic data.


The requirements and setup instructions above include the git project and dataset for this meetup.

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  • Matt H.

    Slides from last night, had to be chopped for size but I included links where relevant:

    2 · December 13, 2013

  • Matt H.

    Thanks so much for your kind words, everyone! It was great to meet all of you and see the results of your hard work on the coding challenge. I'm going to post a short version of the slides as a few of you have asked for them, should be up soon.

    Now go ahead and map something!

    2 · December 13, 2013

  • Hardik

    Matt - Please post the presentation slides, thanks :)

    December 13, 2013

  • Marnie L.

    Excellent speaker, topic, people, food and always...HAPPY HOLIDAYS...C u next year:)

    1 · December 12, 2013

  • Hardik

    Great stuff!! Really admire the work Matt is doing on and off the field, honour to see him.Thanks Dan and Abhi for organizing wonderful meetup up. Agree with Brandon on code participation. Thank you everyone, see you all next year :)

    December 12, 2013

  • David H.

    Great session!

    December 12, 2013

  • Brandon K.

    Great meetup - good format with combination of presentation and live coding. More participation from the audience would be great next time, people should come prepared, be creative and write code.

    December 12, 2013

  • Hardik

    vagran ssh does not seem to work for me

    /home/vagrant/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernal_require.rb:55 in 'require': cannot load such file -- log4r (LoadError)
    from /home/vagrant/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernal_require.rb:55 in 'require'
    from /user/bin/vagrant:2:in '<main>'

    December 12, 2013

    • Hardik

      thanks to abhi, updating vb.gui = true in VagrantFile fixd the problem

      December 12, 2013

  • Hardik

    anyone trying this from windows machine you may get during
    vagrant up

    Command: ["modifyvm", "16d4bcdc-a907-42eb-962f-faef2c68f13c", "--name", "catsAndDogs_1370628358"]

    Stderr: VBoxManage.exe: error: Could not rename the directory 'C:\Users\yourusername\VirtualBox VMs\catsAndDogs_[masked]' to 'C:\Users\yourusername\VirtualBox VMs\catsAndDogs' to save the settings file (VERR_ACCESS_DENIED)
    VBoxManage.exe: error: Details: code E_FAIL (0x[masked]), component SessionMachine, interface IMachine, callee IUnknown
    VBoxManage.exe: error: Context: "SaveSettings()" at line 2527 of file VBoxManageModifyVM.cpp

    couple of ways to resolve this error

    1) in your virtualbox > file > preference change the default path to non-space folder.
    2) downgrade your vagrant to 1.3.2 once your vagrant is up

    it will ask your for precise32 tty1 username and password enter vagrant/vagrant then follow

    December 12, 2013

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