* Install Homebrew from http://mxcl.github.io/homebrew/
* Install the latest version of Ruby: `brew install ruby`
* Install ImageMagick: `brew install imagemagick`
+* Install libxml2: `brew install libxml2 --with-xml2-config`
* Install Bundler: `gem install bundler`
Note that OS X does not have a /home directory by default, so if you are using the GPX functions, you will need to change the directories specified in config/application.yml.