This is a very basic tool for collecting samples of wifi signal strength in an area such as a house, and then making simple heatmap plots. I wrote it for my own use to place wifi access points in my house; it's here in the hope that somebody else will find it useful.

This software currently works only on a Mac, but could probably be made to work on other operating systems by replacing the AirportQuery class with an equivalent that calls a suitable wifi-querying command line tool.

You'll need Python 3, Qt 5, scipy, matplotlib. One way to get these is to install brew then brew install python3 pyqt and pip3 install matplotlib.

No installation is necessary - just run the wifi-heatmap.py program directly - but you can certainly copy it into /usr/bin or similar.

• Use "File/Open Floor Plan..." to load a plan of the area you want to survey, which can be a hand-drawn image (to scale is best), or (ideally) blueprints or architect's plans. Most common image formats will work, although you may want to rescale the image to a manageable size).
• Click on the floor plan corresponding to where you physically are in your house. This will sample all of the wifi networks (this will take a few seconds) and record them on the plan. Walk around the house and take a number of such samples.
• Use "View/Show Heatmap", and select the wifi network you're interested in, to get a heatmap of the signal strength over the entire floor area.
• You can also save the current survey to a simple CSV file.

• Only single surveys are currently supported. If you want to survey a new area, restart the program and load in a new floor plan.
• No undo (although you can edit the CSV file to remove one or more points).