Navigating through the app store I found that there are many applications that offer Wi-Fi scanning options. With them you can map you home, check the available networks, measure the signal and so on.
What I find interesting is that OS X already comes with a utility that would satisfy most of the buyers of this apps.
To find it you can navigate to
/System/Library/CoreServices/ and open the
Wi-Fi Diagnostics.app , or use a shortcut by pressing the alt key while clicking on the airport icon on the top menu bar, then “Open Wi-Fi Diagnostics”
The options that you are presented when you open the application can be not very end user friendly and probably they are more focused on an admin user trying to troubleshoot some network traffic, but the bright side is that if you press cmd+N a new window will open with the network utilities.
In this new window you have a couple tab to monitor the current network signal, list all the available networks with active and passive scans, a very interesting one to list all the bonjour services detected and finally the usual ping, lookup, trace route… with the addition of a couple of IPv6 commands. When you use the command in this last tab the actual command line call is listed so you can take that and integrate in your scripts for example.
Here you have some sample screens: