NetSpot is a free tool for discovering local wireless devices and creating colour-coded heatmaps.

Launch the program and it immediately detects all your local wifi devices, displaying their details in a table: SSID, BSSOD, Signal (current/ min/ max/ average), band, level, width, vendor, security, mode, and when it was last seen.

Clicking any column header sorts by that field. For example, clicking "Channel" groups devices by their channel, helping you spot competition and conflicts.

This isn't just about static figures. NetSpot displays tiny signal graphs within the table, and double-clicking any device shows graphs and tables of its signal over time, along with other interesting details (when and if the channel and security were last changed).

There's also a separate Survey mode which enables collecting and displaying wifi data on custom maps.

What's new in 2.10 (see changelog for more):

- important: macOS Mojave 10.14 will require users to enable location services to run NetSpot.
- added  Japanese localization
- added  Time-limited licenses are available
- improved  When switching among surveys, selected visualization is kept
- improved  The color scheme in the sidebar is more contrasting and visual now
- improved  Updated the list of device vendors
- fixed  Corrected measurement values in some of the visualizations
- fixed  Minor interface improvements, just to make it sleeker

Verdict

A good-looking, powerful yet easy-to-use wifi discovery tool.