Before getting started

Take a look at the code provided with the book. You should see a js folder in which the required libraries are stored. For the first few chapters, ol.js, and ol.css in the ol3-3.11.0 folder will be sufficient. The code is also available on GitHub. You can download a copy from the following URL: https://github.com/GaborFarkas/mastering_openlayers3/releases. Take a look at the following screenshot:

Note

You can download the latest release of OpenLayers 3 from its GitHub repository at https://github.com/openlayers/ol3/releases. For now, grabbing the distribution version (v3.11.0-dist.zip) should be enough.

Creating a working environment

There is a security restriction in front end development, called Cross Origin Resource Sharing (CORS). By default, this restriction prevents the application from grabbing content from a different domain. On top of that, some browsers disallow reaching content from the hard drive when a web page is opened from the file system. To prevent this behavior, please make sure you possess one of the following:

• A running web server (highly recommended)
• Firefox web browser with security.fileuri.strict_origin_policy set to false (you can reach flags in Firefox by opening about:config from the address bar)
• Google Chrome web browser started with the --disable-web-security parameter (make sure you have closed every other instance of Chrome before disabling security)
• Safari web browser with Disable Local File Restrictions (in the Develop menu, which can be enabled in the Advanced tab of Preferences)

Tip

You can easily create a web server if you have Python 2 with SimpleHTTPServer, or if you have Python 3 with http.server. For basic tutorials, you can consult the appropriate Python documentation pages.