We actually did that several years ago in our data viz lab. All of the (willing) lab members tracked their location data and one student developed a way to track and visualize co-occurrences of people over time [1].

Another ways to visualize this kind of information is to use space time cube maps, which turn the time axis into the z-axis for trajectory visualization; GeoTime[2] is the most well known implementation of it AFAIK.

[1] http://profs.etsmtl.ca/mmcguffin/research/2016-gupta-Movemen... [2] https://geotime.com/products/geotime/