With a single glance, the band map allows us to gather an impression on the activity to be found on a band, if there are many new stations or mults, if it's worth calling CQ etc.
Even without packet radio, you can feed spots into the band map using ctrl-Enter. Also, when you log a station, this callsign will be added to the band map. This way you may fill in holes or add new stations in a multi operator environment to prepare a new band for an upcoming QSY. Win-Test will send the spots out to the network so that all networked stations have the same band map.
You may also correct or delete spots from the band map by right clicking on a callsign, which will open up a context menu. Spots in the band map stay for 60 minutes (default setting, may be increased up to 99).
Spots have a bandwidth of 1 kHz by default - meaning that if you enter another call within 1 kHz this will overwrite the current "slot". This setting can be changed however, which is important on CW, where up to 3 stations may co-exist within 1 kHz.
There is also a text version of the band map which will list spots sorted by callsign or by frequency.