A Place is one location you scan, like your home or a relative's house. It holds the Apple Homes and Home Assistant servers there. With HomeMapper Pro, the whole app shows one Place at a time. Pick it on the Scan screen's Place to Scan card, or from the Place menu at the top of Devices, Rooms and Topology.
How HomeMapper matches a Place
HomeMapper identifies a Place from things it finds on that Place's local network. It doesn't use your location or your Wi-Fi network's name. When you open the Scan screen on a network saved to a Place, it selects that Place, and the whole app follows.
On a new network, Start Scan shows a list of Places to pick from. Pick a Place and HomeMapper matches this network to it next time, or tap New Place… to create one. Scan Without Saving Network scans once without saving this network to the Place. When HomeMapper can't find anything on the network to identify a Place by, picking a Place still scans there, but no network is saved to it.
Scanning from somewhere else
You can scan a Place when you're not there. HomeMapper then reads only that Place's Apple Home and Home Assistant, because its network and Thread mesh can only be found on site. The same happens when Local Network permission is off. A Place with no Apple Home and no Home Assistant can only be scanned on its own network.
When you're on another Place's network, Start Scan shows a prompt to confirm whether you're at the Place you picked. Scan From Away, Don't Ask Again turns that prompt off for those two Places.
Two Places on one network
Avoid giving two Places the same network unless you mean to. A scan of either one shows everything on that network, including devices that also belong to the other.
Reset
If the Scan screen keeps selecting the wrong Place, go to Settings → Appearance → Places, Homes & Rooms, swipe the Place to the left and tap Reset, or right-click it on a Mac and choose Reset. This clears the Place's saved networks and every Don't Ask Again answer that names it. Its homes and rooms are kept, and its network is saved again the next time you scan there and pick it.