OS X Yosemite: Manage which apps can use Location Services
Location Services allows apps and websites to gather and use information based on the current location of your Mac. Your approximate location is determined using information from local Wi-Fi networks, and is collected by Location Services in a manner that doesn’t personally identify you.
Apps that you have allowed to use Location Services appear in the Privacy pane of Security & Privacy preferences. Checkboxes show whether Location Services is turned on or off for an app. If you don’t want to allow Location Services for one or more apps, you can turn it off by deselecting the checkbox next to the app. If you turn Location Services off for an app, you’re prompted to turn it on again the next time that app tries to use your location data.
When you use Spotlight or Spotlight Suggestions in Safari, the location of your Mac at the time you submit a search query to Spotlight or Safari is sent to Apple to make Spotlight Suggestions more relevant and to improve other Apple products and services.
You can also turn Location Services off altogether by deselecting Enable Location Services in the Privacy pane of Security & Privacy preferences. Even if you disable Location Services, third party applications and websites may still use other ways to determine your location.
To open the Privacy pane, choose Apple menu > System Preferences, click Security & Privacy, then click Privacy.