Launch NetSpot. By default, the program opens in Discover Mode, that's exactly what you need for a quick snapshot of the nearby WiFi networks. If you are in the Survey mode after your last launch, just switch back using the control on the main toolbar.
You don't need to run a WiFi survey to get a quick overview of the surrounding wireless range. Wait a second or two and the detailed information about existing Wi-Fi networks around you will start appearing in NetSpot.
In previous versions of NetSpot you were supposed to run a tiny "fake" wireless survey on a blank map to scan for wireless networks. Since NetSpot 2.0, this is no longer required as we introduced full-featured Discover Mode. So you get the info about all the networks that are not hidden in a separate list. The list is updated every 5-10-30 seconds. If a network disappears, you can still see it in the list for some time, and find out how long ago it was gone in the Last Seen column.
To pause scanning for Wi-Fi networks, just click the Pause button on the lower toolbar. Scanning will stop until you restart it. If you see too many networks on the list, you can filter them by SSID (name) or BSSID (MAC-address).
NetSpot's Discover Mode provides detailed info on each wireless network, the list of visible parameters is configurable if you secondary-click the table's header. Usually you would be interested in the network's name, BSSID, vendor, mode, network security, wireless channel, signal level, Signal-to-Noise Ratio and more.
You can visualize and export historical values sorted by time for the networks discovered. To see historical data visualized in a live graph, click Details on the lower toolbar. To export this data into CSV, click Export on the main toolbar.
That's all there is to it! You now have completed your Wi-Fi scan and have a complete list of the available wireless networks in your area. With this information you can choose the Wi-Fi network you wish to connect to or quickly find the one that interferes with yours. NetSpot offers the best WiFi scanning features among all WiFi scanners for Mac and (unlike some others) the Discover Mode is available in the completely free edition of NetSpot.