LinSSID
LinSSID fills the gap of a graphical WLAN scanner, after the InSSider is apparently no longer developed for Linux. The development of LinSSID is also slow; the last update found on the Sourceforge project page dates back to 2018.
But the program can still be installed in its latest version from Ubuntu’s Universe repository and does what it should do, provided that the own user account belongs to the group of administrators: With a click on Start, LinSSID scans the location in the 2.4 and (if available) 5 MHz band and prepares the result graphically: either on a time axis or as a diagram with channel/signal strength.
Installation
sudo apt install linssid
Alternativen
Keine für Linux bekannt.