Google releases Comunity Reports
Google released a report for each country they are collecting users movement data in an aggregated form. It reveals the popular places, compared to an earlier time frame in February 2020. The data of the current report was released on March 29th summarizing the movement of the 2..3 days before the report. Very drastic the differences between Italy and US, you can clearly see how one country after another only starts to shut down public life. A excellent use of the data with full respect to privacy.
Path Inaccuracy – Mobile Phone in the pocket
I noticed the accuracy of the path (recorded by Android/Google) depends a lot on the phone’s exposure to the GPS signal (no surprise). The below sample path (carrying the phone in the pocket of my jacket) demonstrates this. The red/orange dots reflect the correct path, while the blue line is the Google interpretation, obviously interpolating a straight line between location recordings. It works better for places where I have been stationary for a while. Take-away: With Googles location tracking alone we don’t achieve enough accuracy to stop the infection by identifying meeting points or overlaps of data.
Note: This is not a comment against Google or the tracking feature, it highlights potential weakness in the data acquisition process. The feature is an optional setting and can be switched on and off in the configuration of any Android phone.